1Prepared By: SREEKAR REDDY DUPPALLI Capt. MUDULI answers by SREEKAR DUPPALLI Weather Fronts Principle Fronts are zones of transition between two different air masses. The zone may be 20 miles across or it may be 100 miles across, but from one side of a front to the other, one clearly would sense that the properties of an air mass had changed significantly (e.g., contrasts in temperature and dew point, wind direction, cloud cover, and on-going weather). The frontal zone represents the leading edge of a wedge of cold/cool air. If the wedge is moving into an area of warmer air, the front is called a cold front. If the wedge is retreating and warmer air is moving into an area previously occupied by cool air, the front is termed a warm front. Figure 1 - Types of Fronts Chief Mate’s Oral preparation
[email protected] Capt. Muduli FUN 1 2 Prepared By: SREEKAR REDDY DUPPALLI Definition Fronts are boundaries between air masses of different temperatures. Fronts are actually zones of transition, but sometimes the transition zone, called a frontal zone, can be quite sharp. The type of front depends on both the direction in which the air mass is moving and the characteristics of the air mass. There are four types of fronts that will be described below: cold front, warm front, stationary front, and occluded front. To locate a front on a surface map, look for the following: o sharp temperature changes over relatively short distances, Chief Mate’s Oral preparation
[email protected] Capt. Muduli FUN 1 3 Prepared By: SREEKAR REDDY DUPPALLI o changes in the moisture content of the air (dew point), o shifts in wind direction, o low pressure troughs and pressure changes, and o clouds and precipitation patterns. Not all of these patterns may be obvious or even occur, but these are some signs. Figure 2 - Side View of a Typical Cold Front Cold Fronts Cold front- a front in which cold air is replacing warm air at the surface. Some of the characteristics of cold fronts include the following: o The slope of a typical cold front is 1:100 (vertical to horizontal). o Cold fronts tend to move faster than all other types of fronts. Chief Mate’s Oral preparation
[email protected] Capt. Muduli FUN 1 com Capt. Muduli FUN 1 . strong thunderstorms along and ahead of the front. cold fronts move into Oklahoma mainly from the Canadian prairies but sometimes from the Arctic Circle or the eastern Pacific. o Cold fronts tend to move the farthest while maintaining their intensity. In winter. Cold fronts almost always are easier to locate on a weather map than are warm fronts. Chief Mate’s Oral preparation sreekarduppalli@hptmail. primarily because of the strength of the high pressure system to the north and west of the cold front compared to that north of a warm front. 4 Prepared By: SREEKAR REDDY DUPPALLI o Cold fronts tend to be associated with the most violent weather among all types of fronts. o Cold fronts can be associated with squall lines (a line of strong thunderstorms parallel to and ahead of the front). o Cold fronts tend to be associated with cirrus well ahead of the front. and a broad area of clouds immediately behind the front (although fast moving fronts may be mostly clear behind the front). clearing skies. o Warm fronts tend to move slowly. Some of the characteristics of warm fronts include the following: o The slope of a typical warm front is 1:200 (more gentle than cold fronts). Chief Mate’s Oral preparation sreekarduppalli@hptmail. o Warm fronts are typically less violent than cold fronts. 5 Prepared By: SREEKAR REDDY DUPPALLI Cold fronts usually bring cooler weather. warm fronts are more likely to be associated with large regions of gentle ascent (stratiform clouds and light to moderate continuous rain). Muduli FUN 1 .Side View of a Typical Warm Front Warm Fronts Warm front.a front in which warm air replaces cooler air at the surface. o Warm fronts are usually preceded by cirrus first (1000 km ahead). and a sharp change in wind direction. o Although they can trigger thunderstorms.com Capt. Figure 3 . a front that does not move or barely moves. Chief Mate’s Oral preparation sreekarduppalli@hptmail. cloud formation. to the east of a surface low pressure area. skies are relatively clear (but change gradually). Stationary Fronts Stationary front. then stratus and possibly fog. it will be northeast of the cold front and often. to some form of precipitation. Muduli FUN 1 . Clouds and precipitation are quite prevalent to the north of the warm front. This results from the fact that low-level southerly winds in the "warm sector" of the cyclone rise up and over the cooler. and. o Warm fronts are associated with a frontal inversion(warm air overrunning cooler air).com Capt. ultimately. o Behind the warm front. more dense air at the surface located north of the warm front. 6 Prepared By: SREEKAR REDDY DUPPALLI then altostratus or altocumulus (500 km ahead). If a warm front exists on a weather map. The lifting leads to saturation. In Oklahoma. warm fronts are rare in the winter and non-existent in the summer. Many times the winds on both sides of a stationary front are parallel to the front.g. Figure 4 .com Capt. cold fronts which stall). Typically stationary fronts form when polar air masses are modified significantly so as to lose their character (e. 7 Prepared By: SREEKAR REDDY DUPPALLI Stationary fronts behave like warm fronts. but are more quiescent. Muduli FUN 1 .Development of an Occluded Front Chief Mate’s Oral preparation sreekarduppalli@hptmail.. What is upwelling? Upwelling is a process in which deep.e. Occluded fronts are indicative of mature storm systems (i. those about to dissipate). Chief Mate’s Oral preparation sreekarduppalli@hptmail. The weather ahead of the cold occlusion is similar to that of a warm front while that along and behind the cold occlusion is similar to that of a cold front. an occluded front is formed. Muduli FUN 1 .. cold water rises toward the surface. The most common type of occlusion in North America is called a cold-front occlusion and it occurs when the cold front forces itself under the warm front. 8 Prepared By: SREEKAR REDDY DUPPALLI Occluded Fronts Because cold fronts move faster than warm fronts. When they do. they can catch up to and overtake their related warm front.com Capt. Stationary Front a front that is not moving When a warm or cold front stops moving. Winds blowing across the ocean surface push water away. this is shown by an inter-playing series of blue spikes pointing one direction and red domes pointing the other. A noticeable temperature change and/or shift in wind direction is commonly observed when crossing from one side of a stationary front to the other. A stationary front is a pair of air masses.” also occurs when wind causes surface water to build up along a coastline and the surface water eventually sinks toward the bottom. Muduli FUN 1 . This process is known as “upwelling.com Capt. called “downwelling. Once this boundary resumes its forward motion. Chief Mate’s Oral preparation sreekarduppalli@hptmail. nutrient-rich water that “wells up” from below. Therefore. These nutrients “fertilize” surface waters. The reverse process. neither of which is strong enough to replace the other. it becomes a stationary front. it once again becomes a warm front or cold front. On a weather map. A stationary front is represented by alternating blue and red lines with blue triangles pointing towards the warmer air and red semicircles pointing towards the colder air. good fishing grounds typically are found where upwelling is common. Water that rises to the surface as a result of upwelling is typically colder and is rich in nutrients.” Upwelling occurs in the open ocean and along coastlines. meaning that these surface waters often have high biological productivity. 9 Prepared By: SREEKAR REDDY DUPPALLI This graphic shows how displaced surface waters are replaced by cold. Water then rises up from beneath the surface to replace the water that was pushed away. com Capt. Or the front may break apart. Because a stationary front marks the boundary between two air masses. a stationary front is shown as alternating red semicircles and blue triangles like in the map at the left. This happens when two masses of air are pushing against each other but neither is powerful enough to move the other. discrete atmospheric bodies of unified weather characteristics. If the wind direction changes the front will start moving again. Muduli FUN 1 . Most familiar are cold and warm fronts. especially if the front is in an area of low atmospheric pressure. What Kind of Weather Occurs Along a Stationary Front? Fronts refer to the boundaries between air masses. The blue triangles point in one direction and the red semicircles point in the opposite direction. The weather is often cloudy along a stationary front and rain or snow often falls. 10 Prepared By: SREEKAR REDDY DUPPALLI Stationary Fronts A stationary front forms when a cold front or warm front stops moving. On a weather map. A stationary front may stay put for days. which are large. there are often differences in airtemperature and wind on opposite sides of it. becoming either a cold or warm front. which bring Chief Mate’s Oral preparation sreekarduppalli@hptmail. Winds blowing parallel to the front instead of perpendicular can help it stay in place. that are sometimes produced along stationary fronts. promoting flooding in areas within its influence. or where air masses equally matched stall one another’s movements. at least near Earth’s surface. A cold front is illustrated with a line of blue triangles pointed in the direction of travel and thus toward warmer air. A stationary front is shown as a combination of the two: a bead of interlocked red warm- Chief Mate’s Oral preparation sreekarduppalli@hptmail. particularly those overtaken in forested areas -. Downdrafts from frontal thunderstorms may shunt high winds downward off the jet stream to birth derechos. In North America. stationary fronts may provoke more extreme weather. air may be significantly moving about higher up in the atmosphere. however. These tempests may be hundreds of kilometers long and howl at 160 kilometers per hour (100 mph) or more. conditions resemble those encountered along warm fronts: extensive cloudiness and showers. Severe Weather Occasionally. A derecho is a fast-moving belt of powerful straight-line winds -. they mostly develop in spring and summer east of the Rockies. given a shift in upper-level winds or the relative strength of one or another of the air masses. or.and sometimes violent storms -.com Capt. A stationary front can eventually dissipate. different fronts are depicted by symbols of varying color and arrangement. such overcast and precipitation may persist for days.and the general instability of the local atmosphere.or mobile homes.their moisture levels. it becomes a so-called stationary front. Often. If a cold or warm front halts.produced as one air mass is forced upward by another. Such a front may form when upper-level winds that had previously propelled a front along shift and flow parallel to it. 11 Prepared By: SREEKAR REDDY DUPPALLI about notable changes in temperature and are often accompanied by the cloudiness and precipitation -. Series of thunderstorms or heavy rain showers may be shafted down the front. for example -. As a stationary front can be durable. often bowed outward and fast-advancing. Muduli FUN 1 . a warm front is shown as a line of red semi-circles pointed toward colder air. Derechos are important agents of ecological disturbance and potentially lethal hazards to humans. Typical Weather The exact weather of a stationary front depends greatly on the characteristics of its constituent air masses -. might resume mobility as a cold or warm front. Symbology On a weather map.the name comes from the Spanish word for "direct" -. Stationary Front Basics A stationary front is an unmoving one.the windstorms can flatten entire tracts of timber -. Even though the surficial front may be basically stable. Neither abutting air mass has the power to shove through the other. 12 Prepared By: SREEKAR REDDY DUPPALLI front semicircles and blue cold-front triangles. This forms an occluded front. which is the boundary that separates the new cold air mass (to the west) from the older cool air mass already in place north of the warm front. an occluded front is drawn with a solid purple line. Muduli FUN 1 . On colored weather maps. Symbolically. As the storm intensifies. North of the warm front is a mass of cooler air that was in place before the storm even entered the region. each oriented toward the respective opposing air mass. Chief Mate’s Oral preparation
[email protected] Capt. the cold front rotates around the storm and catches the warm front. Occluded Front when a cold front overtakes a warm front A developing cyclone typically has a preceding warm front (the leading edge of a warm moist air mass) and a faster moving cold front (the leading edge of a colder drier air mass wrapping around the storm). an occluded front is represented by a solid line with alternating triangles and circles pointing the direction the front is moving. 13 Prepared By: SREEKAR REDDY DUPPALLI Changes in temperature. Muduli FUN 1 .com Capt. Common characteristics associated with occluded fronts have been listed in the table below. and wind direction can occur with the passage of an occluded front. winds were from the west-southwest. The lower dew point temperatures behind the front indicate the presence of drier air. temperatures ahead (east of) the front were reported in the low 40's while temperatures behind (west of) the front were in the 20's and 30's. dew point temperature. East of the front. sometimes Tcu and Cb Ns. Ns light. moderate or heavy light-to-moderate light. A noticeable wind shift also occurred across the occluded front. Before Passing While Passing After Passing Winds southeast-south variable west to northwest Temperature Cold Type cold-cool dropping colder Warm Type cold rising milder Pressure usually falling low point usually rising in order: Ci. As or scattered Cu As. moderate or Precipitation continuous precipitation or precipitation followed by heavy precipitation showers general clearing Chief Mate’s Oral preparation sreekarduppalli@hptmail. In the map below. Clouds Ns. Cs. winds were reported from the east-southeast while behind the front. Muduli FUN 1 . To the north of the warm front is the cool air that was in the area before the depression developed: The warm air mass is replacing this cool air and at its leading edge is a warm front. although may Dew Point steady especially if cold-occluded rise a bit if warm-occluded What is an Occluded Front? Occluded fronts are linked with areas of low pressure called depressions (more on these soon!). The diagram below shows this.com Capt. 14 Prepared By: SREEKAR REDDY DUPPALLI poor in Visibility poor in precipitation improving precipitation usually slight drop. slight drop. there is usually a warm front and a faster moving cold front. When a depression forms. Chief Mate’s Oral preparation sreekarduppalli@hptmail. com Capt. This is shown below. the cold front catches up with the warm front (remember it moves faster than the warm front). you would feel changes in temperature and wind speed. Chief Mate’s Oral preparation sreekarduppalli@hptmail. 15 Prepared By: SREEKAR REDDY DUPPALLI As the depression intensifies. Occluded fronts can generate quite stormy weather as they pass over. Muduli FUN 1 . The line where the two fronts meet is called an occluded front: When an occluded front passes overhead. the cold front is likely to overtake the warm front. an occluded front looks like a purple line with half triangles and half semicircles along it pointing in the direction that the front is moving. like the one on the left. After the front passes. Because cold fronts move faster. It ends at a low pressure area shown with a large ‘L’ on the map. the sky is usually clearer and the air is drier. Muduli FUN 1 . the cold air mass from the cold front meets the cool air that was ahead of the warm front. Chief Mate’s Oral preparation sreekarduppalli@hptmail. There is often precipitation along an occluded front from cumulonimbus or nimbostratus clouds. and at the other end connects to cold and warm fronts. This is known as an occluded front. At an occluded front. Wind changes direction as the front passes and the temperature changes too. The temperature may warm or cool. 16 Prepared By: SREEKAR REDDY DUPPALLI Occluded Fronts Sometimes a cold front follows right behind a warm front. On a weather map. The warm air rises as these air masses come together. A warm air mass pushes into a colder air mass (the warm front) and then another cold air mass pushes into the warm air mass (the cold front). Occluded fronts usually form around areas of low atmospheric pressure.com Capt. A stationary front has the triangles on one side and the semi-circles on the other. This process can take several days. In most cases. They appear on the same side of the front and are always on the side that the front it moving towards. the low pressure storm system will slowly begin to dissipate once this happens since the warm air source is being cut off from the center of the storm. This usually happens when the storm reaches its peak intensity. The front is represented on a map with both the triangles of a cold front and the semi-circles of a warm front. The low pressure area will then fill and the pressure will slowly rise.com Capt. Overview of the provisions What does the Polar Code mean for ship safety Chief Mate’s Oral preparation sreekarduppalli@hptmail. 17 Prepared By: SREEKAR REDDY DUPPALLI What is an Occluded Front? An occluded front occurs when a cold front overtakes the warm front in a low pressure storm system or an extra-tropical storm. Precipitation will diminish and the winds will lessen. Muduli FUN 1 . com Capt. 18 Prepared By: SREEKAR REDDY DUPPALLI Chief Mate’s Oral preparation sreekarduppalli@hptmail. Muduli FUN 1 . com Capt. Muduli FUN 1 . 19 Prepared By: SREEKAR REDDY DUPPALLI How the Polar Code protects the environment: Chief Mate’s Oral preparation sreekarduppalli@hptmail. search and rescue requirements related to the potential hazards of operating in polar regions. south at 58° . Existing and new ships certified under MARPOL shall comply with the environmental requirements by 1 January 2017. equipment. The areas are as follows: Arctic: In general north of 60° but limited by a line from Greenland. including ice. construction. This means that fishing vessels (that carry MARPOL certificates) will also have to comply with the environmental part of the code. IV and V respectively. although not carrying any SOLAS certificates. southern shore of Jan Mayen . after 1 January 2018. II. Dedicated document requirement lists will be provided. It is written in a goal based manner and provides both functional requirements and detailed requirements.com Capt. Antarctic: South of 60°.Bjørnøya – Cap Kanin Nos. All ships: To obtain the certificate the manager of existing ships should submit the following to DNV GL: Report of an operational assessment with hazards of the intended operations based on the sources of hazards listed in the Code (Hazard analysis) Chief Mate’s Oral preparation sreekarduppalli@hptmail. whichever occurs first. and to all passenger ships. i.north of Iceland. training. Muduli FUN 1 . The environmental part of the Polar Code applies to all ships certified under MARPOL Annexes I. Documentation Requirements Polar Ship certificate: The safety part of the code has design. cargo ships of 500 GT or more. remoteness and severe and rapidly changing weather conditions. Ships constructed before 1 January 2017 shall comply with the safety part of the Polar Code by the first intermediate or renewal survey. operational. 20 Prepared By: SREEKAR REDDY DUPPALLI Application Only vessels that intend to operate within the Arctic and Antarctic areas as defined in the Polar Code need to comply with the code.e. Ships constructed on or after 1 January 2017 shall comply with the safety part of Polar Code at delivery. The safety part of the Polar Code applies to ships certified under SOLAS. Documentation of systems and equipment (to be) installed in order to comply with the Code and that this is fully functional at the established polar service temperature (PST) for the vessel.2 The Environmental requirements (MARPOL related) of the Polar Code: Existing ships: Environmental requirements in the Polar Code are operational and therefore the responsibility of the master. 21 Prepared By: SREEKAR REDDY DUPPALLI A PWOM – Polar Water Operational Manual. This can/shall be done by the surveyor at the initial Polar Code survey. Operational requirements.com Capt. Intact stability calculations that include allowance for icing according to the Polar Code Reg. the ship is built to an ice class) but must be submitted and approved for new ships: For Polar Class category A: Hull drawings/scantlings and scantlings of propeller blades referring to Polar Class 1-5 For Polar Class category B: Hull drawings/scantlings and scantlings of propeller blades referring to Polar Class 6-7 New ships: Additional requirements: For Polar Class categories A and B ships the following must be submitted: Damage Stability calculation in accordance with the requirements in Polar Code Reg.e. Chief Mate’s Oral preparation sreekarduppalli@hptmail. The PWOM shall address the challenges found in the Hazard Analysis and document the practical operation of the ship in polar waters. In short these are: P&A manual The P&A manual (where required) need to be amended and endorsed. through 15 ppm OWS) MARPOL manuals and records to take into account operation in polar waters. Muduli FUN 1 .3. 4.3. The following design drawings are assumed already approved for existing ships if relevant (i.e. 4. as: All discharge of oil prohibited (i. com Capt. Muduli FUN 1 . a tank plan showing that all oil fuel tanks are separated from the outer shell (related to MARPOL requirements of the code). Operational requirements: Discharge of untreated sewage from cat A and B cargo ships and passenger ships of all categories is prohibited. MARPOL certificates: At the next IOPP renewal survey the appendix to the IOPP certificate will be reissued with a tick-off mark for compliance with the environmental requirements of the Polar Code. 22 Prepared By: SREEKAR REDDY DUPPALLI Sewage discharge restrictions near ice (treated 3nm. for continued validity of the certificate. The certificate will be harmonized with the validity of the corresponding SOLAS certificate (CCC. Chief Mate’s Oral preparation sreekarduppalli@hptmail. In urgent cases the Polar Ship Certificate may (after document verification and approval at the approval site/office) be issued without survey. PSSC). an on-board survey should be undertaken at the next scheduled survey. chief mates and officers in charge of a navigational watch shall be qualified in accordance with the STCW Convention and Code (not relevant for ice free conditions). The other MARPOL certificates are unaffected. Where oil and noxious liquid substances tanks. Certification Polar Ship certificate: Upon verification and approval of the submitted documentation the vessel can be surveyed and the appropriate Polar Ship Certificate can be issued. New ships: Ships of Polar Class category C: No additional requirements Ships of Polar Class category A and B (or equivalent ice class): Documentation to be submitted: With an aggregate oil fuel capacity of less than 600 m3. 12 nm. In this case. For existing ships of Polar Class category C. double bottom of minimum 760 mm. Garbage discharge restrictions near ice. untreated 12 nm). 12. Ch. masters. Manning and training: In accordance with Part I-A. Their patterns are determined by wind direction. Coriolis forces from the Earth’s rotation. and deep circulation. Chief Mate’s Oral preparation sreekarduppalli@hptmail. Currents may also be generated by density differences in water masses caused by temperature and salinity variations.com Capt. Currents are cohesive streams of seawater that circulate through the ocean. which sweeps along the deep-sea floor. 23 Prepared By: SREEKAR REDDY DUPPALLI Recommendations Managers are recommended to contact DNV GL to initiate the approval process before the certificate is needed. Surface wind-driven currents generate upwelling currents in conjunction with landforms. and heat with them. oxygen. density differences in water masses caused by temperature and salinity variations. and the position of landforms that interact with the currents. Managers should perform an operational assessment and develop a PWOM as soon as possible. creating deepwater currents. gravity. Muduli FUN 1 . Ocean currents can be generated by wind. DNV GL can provide support here as well. Surface currents are generated largely by wind. These currents move water masses through the deep ocean—taking nutrients. There are two distinct current systems in the ocean—surface circulation. while others are vast flows that take centuries to complete a circuit of the globe. Some are short- lived and small. which stirs a relatively thin upper layer of the sea. and events such as earthquakes. and the gravitational pull of the Moon. fine grained or coarse. Q: What causes ocean currents? A: QUICK ANSWER Wind. the coriolis effect produced by the Earth's rotation. These currents may be divided into two categories: surface currents. Huge storms move water masses. Bottom substrate (material) determines what kinds of communities may develop in an area. account for the bulk ocean currents. creating turbidity currents strong enough to snap submarine communication cables. Underwater earthquakes may trigger devastating tsunamis. when a current that is moving over a broad area is forced into a confined space. while deep water currents. which are driven largely by wind. and deep water currents. Finally. Earthquakes may also trigger rapid downslope movement of water-saturated sediments. such as earthquakes. Ocean currents are complex systems responsible for moving tremendous amounts of seawater as well as storing. Bottom currents scour and sort sediments. Currents of seawater are very similar to air currents and other atmospheric patterns in that currents typically adhere to a regular set of specific patterns. water density and salinity all play a role in generating ocean currents. transporting and realising thermal energy caused by solar radiation. which are influenced more heavily by temperature variations and differences in water salinity. it may become very strong. Currents may also be influenced by external forces. Large weather Chief Mate’s Oral preparation sreekarduppalli@hptmail. Both move masses of water inland when they reach shallow water and coastlines. FULL ANSWER Ocean currents are cohesive streams that circulate seawater throughout the oceans of the world. Surface currents only impact a very thin layer of seawater at the surface. water masses forced through narrow openings in a ridge system or flowing around a seamount may create currents that are far greater than in the surrounding water—affecting the distribution and abundance of organisms as well as the scientists and their equipment seeking to study them. Muduli FUN 1 . which occur at depths greater than 400 meters.com Capt. 24 Prepared By: SREEKAR REDDY DUPPALLI Occasional events also trigger serious currents. temperature differences. thus affecting what kind of bottom develops in an area—hard or soft. which may temporarily influence or shift currents. These currents may occasionally be disrupted by outside forces. On the ocean floor. (c) If there is sufficient sea room. made in ample time and with due regard to the observance of good seamanship. if the circumstances of the case admit. (iii) A vessel the passage of which is not to be impeded remains fully obliged to comply with the Rules of this part when the two vessels are approaching one another so as to involve risk of collision. when required by the circumstances of the case.com Capt. Rule 8 Action to avoid collision (a) Any action to avoid collision shall be taken in accordance with the Rules of this Part and shall. (ii) A vessel required not to impede the passage or safe passage of another vessel is not relieved of this obligation if approaching the other vessel so as to involve risk of collision and shall. a vessel shall slacken her speed or take all way off by stopping or reversing her means of propulsion. take early action to allow sufficient sea room for the safe passage of the other vessel. while underwater earthquakes have the potential to trigger devastating tsunamis. be large enough to be readily apparent to another vesselobserving visually or by radar. Chief Mate’s Oral preparation sreekarduppalli@hptmail. (b) Any alteration of course and/or speed to avoid collision shall. 25 Prepared By: SREEKAR REDDY DUPPALLI systems. storms and hurricanes may impact surface currents. if the circumstances of the case admit. (f) (i) A vessel which. (e) If necessary to avoid collision or allow more time to assess the situation. alteration of course alone may be the most effective action to avoid a close quarters situation provided that it is made in good time. Muduli FUN 1 . by any of these Rules. be positive. a succession of small alterations of course and/or speed should be avoided. (d) Action taken to avoid collision with another vessel shall be such as to result in passing at a safe distance. The effectiveness of the action shall be carefully checked until the other vessel is finally past and clear. is required not to impede the passage or safe passage of another vessel shall. when taking action. is substantial and does not result in another close-quarters situation. have full regard to the action which may be required by the Rules of this part. 26 Prepared By: SREEKAR REDDY DUPPALLI Small alterations of course should be avoided Rule 13 Overtaking (a) Notwithstanding anything contained in the Rules of Part B, sections I and II, any vessel overtaking any other shall keep out of the way of the vessel being overtaken. Note that the focus is on ANY vessel overtaking another. That means that regardless that you might be sailing a yacht you must still keep out of the way of a power driven vessel if you are overtaking them. (b) A vessel shall be deemed to be overtaking when coming up with another vessel from a direction more than 22.5 degrees abaft her beam, that is, in such a position with reference to the vessel she is overtaking, that at night she would be able to see only the sternlight of that vessel but neither of her sidelights. (c) When a vessel is in any doubt as to whether she is overtaking another, she shall assume that this is the case and act accordingly. Doubt about whether you are overtaking is more likely to happen during the day. For example if you were approaching from green 110º you would be crossing, but from green 115º you would be overtaking. At night a stern light would clearly indicate the difference, but in daytime it is less easy to determine accurately. (d) Any subsequent alteration of the bearing between the two vessels shall not make the overtaking vessel a crossing vessel within the meaning of these Rules or relieve her of the duty of keeping clear of the overtaken vessel until she is finally past and clear. Chief Mate’s Oral preparation
[email protected] Capt. Muduli FUN 1 27 Prepared By: SREEKAR REDDY DUPPALLI Note that when overtaking another vessel you should allow sufficient room before crossing their bow. If possible it may be a better idea to allow the other vessel to pass ahead and go behind their stern instead of crossing their bow. Chief Mate’s Oral preparation
[email protected] Capt. Muduli FUN 1 28 Prepared By: SREEKAR REDDY DUPPALLI Overtaking can be a dangerous manoeuvre because all moving vessels are surrounded by a pressure wave. High pressure at the ends and low pressure (suction) at the sides. The diagram below shows this effect, which can be very pronounced in a narrow channel or in shallow waters. The pressure wave from a large overtaking vessel can easily cause a smaller one to swing uncontrollably. As the large vessel approaches, its pressure wave pushes the stern of the other vessel further away, causing the bow to swing in and bring the smaller vessel directly to collision, or close enough so that she can be sucked in to collide with the side as the big ship passes. Therefore an overtaking vessel should keep well clear and the vessel being overtaken should, if possible, slow down so that it takes less time to complete the manoeuvre. Pressure zone around a vessel as it moves through the water Interaction between vessels as one vessel passes the other Chief Mate’s Oral preparation
[email protected] Capt. Muduli FUN 1 so that fog signals or engines of other vessels can be heard. If a vessel looms into view through the mist. In restricted visibility. The Rules of Section I particularly affected by this requirement are 5. This requirement also implies hand steering where auto-pilot is normally used. probably outside and maybe right forward. If so. ‘Pay due regard’ means ‘give adequate attention to’. you are in sight of one another and must immediately begin to apply the Rules of Section II. (d) A vessel which detects by radar alone the presence of another vessel shall determine if a close-quarters situation is developing and/or risk of collision exists. Exactly how restricted the visibility must be to demand such action is not specified in the Rules and opinions vary. 7 and 8 – Lookout. provided that when such action consists of an alteration of course. A power-driven vessel shall have her engines ready for immediate manoeuvre. Risk of Collision and Avoiding Action. so far as possible the following shall be avoided: Chief Mate’s Oral preparation sreekarduppalli@hptmail. usually resulting in a slight fall in speed and fuel economy.com Capt. In other words we would be expected to post extra lookouts day or night. The Rules of Section I are those which apply in ‘any visibility’. own ship’s manoeuvrability would be a major influence in choice of speed. Muduli FUN 1 . Later on we will learn the difference between the fog signals of Rule 35 and those of Rule 34 which apply only if you can see the other vessel (b) Every vessel shall proceed at a safe speed adapted to the prevailing circumstances and conditions of restricted visibility. (c) Every vessel shall have due regard to the prevailing circumstances and conditions of restricted visibility when complying with the Rules of Section I of this Part. including the ability to reduce speed immediately. she shall take avoiding action in ample time. 29 Prepared By: SREEKAR REDDY DUPPALLI Rule 19 Conduct of vessels in restricted visibility (a) This Rule applies to vessels not in sight of one another when navigating in or near an area of restricted visibility. What this paragraph actually means is that we must give extra consideration to those Rules as a result of the poor visibility. Depending on the stopping power and manoeuvrability of the ship it might be appropriate when visibility has fallen to about 5 miles in areas known to be subject to sudden onset of fog. On some vessels it may take several minutes to prepare the engines for manoeuvring. You also use different sound signals. action should be taken before they reach the inner third. 30 Prepared By: SREEKAR REDDY DUPPALLI Not surprisingly. This creates a long ‘shadow’ sector where small craft can not be seen either visually or by radar. For larger vessels in the open sea is has been suggested that using a 12-mile range scale. It should always be remembered that small timber or fibreglass vessels often do not return an echo until they are quite close to the ‘searching’ radar. In restricted visibility. Since fog signals (for vessels over 200 metres) have to be audible for 2 miles. this has become the generally accepted distance at which a close quarters situation might be said to begin. Chief Mate’s Oral preparation sreekarduppalli@hptmail. Close quarters situations can develop from astern as well as ahead. an area of the screen which may be obscured with sea clutter. the courts have found that the phrase ‘close quarters situation’ is open to argument. Muduli FUN 1 . A good radar lookout includes frequent changes of range to determine whether this is happening. If we keep to the fog signal analogy it would be half a mile for vessels below 20 metres. On some large vessels. other than for a vessel being overtaken. (i) an alteration of course to port for a vessel forward of the beam.com Capt. There is no ‘stand-on’ or ‘give-way’ in Rule 19. every vessel must take avoiding action—not only if there is a risk of collision but also if a close quarters situation is developing. For smaller manoeuvrable vessels it could be considered rather less. That applies only when vessels are in sight of one another. Smaller vessels might do likewise on a lower range scale. Small vessels should deploy properly designed radar reflectors whenever possible. targets should be assessed while in the outer third of the screen and if a close quarters situation is developing. the conning position and radar scanner can be more than 200 metres from the bow. She shall if necessary take all her way off and in any event navigate with extreme caution until danger of collision is over. 31 Prepared By: SREEKAR REDDY DUPPALLI (ii) an alteration of course towards a vessel abeam or abaft the beam. shall reduce her speed to the minimum at which she can be kept on her course. or which cannot avoid a close quarters situation with another vessel forward of her beam. ‘Abeam’ means at right angles anywhere along the ship’s length. The words ‘so far as possible’ are included in case an alteration to port is necessary due to lack of sea room or the presence of other vessels. Close quarters situations can develop from astern as well as ahead. There is no ‘stand-on’ or ‘give-way’ in Rule 19. (e) Except where it has been determined that a risk of collision does not exist. The Rule phrases this in such a way as to emphasise that you have specifically determined by use of radar that there is no risk of collision. every vessel must take avoiding action—not only if there is a risk of collision but also if a close quarters situation is developing. Such action must be made as early as possible and as boldly as possible. ‘Abeam’ means at right angles anywhere along the ship’s length. That applies only when vessels are in sight of one another. Muduli FUN 1 . The words ‘so far as possible’ are included in case an alteration to port is necessary due to lack of sea room or the presence of other vessels. and ensured that any fog signals from forward of Chief Mate’s Oral preparation sreekarduppalli@hptmail. Such action must be made as early as possible and as boldly as possible. In restricted visibility.com Capt. every vessel which hears apparently forward of her beam the fog signal of another vessel. from the vessel which you think they are from. remembering that the direction of sound in fog can be very deceptive. in fact. Muduli FUN 1 . Chief Mate’s Oral preparation sreekarduppalli@hptmail. AND (3) Navigate with extreme caution. It is also difficult to determine quickly from a radar target. We must: (1) Reduce speed to steerage way (2) Take all way off if necessary. you need to know which way the other ship is heading with respect to your own vessel. This is called her aspect and it can not be determined from a fog signal. It tells us exactly what to do if: (1) we hear a fog signal apparently forward of the beam OR (2) we can not avoid a close quarters situation with another vessel forward of the beam. 32 Prepared By: SREEKAR REDDY DUPPALLI the beam have been positively identified and do not pose a threat – that they are. A radar plot as shown could represent a vessel with aspect Red 30º as sketched next to it. Before altering course to avoid a collision.com Capt. regulation 15-1 requires all tankers of 20.000 tonnes deadweight and above. chemical and gas tankers. 33 Prepared By: SREEKAR REDDY DUPPALLI On the other hand.com Capt. while remaining head on to the danger so as to present a smaller target. including oil. Emergency towing arrangements for tankers SOLAS 1974 Chapter V. to be provided with an emergency towing Chief Mate’s Oral preparation sreekarduppalli@hptmail. Muduli FUN 1 . If radar indicates an unavoidable close quarters situation with a vessel approaching from ahead or within about 30° of the bow. a vessel would be expected to reverse engines and take all way off. it could also represent the two situations below. as the Chief Mate’s Oral preparation sreekarduppalli@hptmail. and had been installed on board North Sea shuttle tankers in the Statfjord field. For existing vessels. This requirement has been in force since 1st January 1996 for new vessels built after that date. The IMO’s guidelines MSC 35 (63). The aft arrangement must be possible to rig in 15 minutes under harbour conditions. the process of drafting regulations for an emergency towing arrangement for tankers was accelerated and draft regulations were presented by IMO’s Maritime Safety Committee in May 1994. it probably dates back to the days of sailing vessels and steamers. A "towline" was introduced in 1912 in Det norske Veritas’ (DnV) rules for both sailing vessels and steamers. and they eventually disappeared from larger vessels. Sailors may remember that they used to store and grease a thick wire on a drum within the forecastle.000 tonnes deadweight must therefore have such arrangement in place. With vessels growing in size. and in the 1960’s the steel wire was so thick and heavy that all sailors knew pretty well that they would hardly be able to move it out of the forecastle in case of need. but not later than 1st January 1999. The arrangements need to be kept simple. a fact that did not add to a seaman’s conception of its usefulness. When the fully loaded oil tanker "BRAER" foundered off the coast of Shetland in 1993. Such arrangements had already been designed in the mid 1980’s. require an emergency towing arrangement to be fitted to the forward and aft end of the tanker. and there may not be much time available before the vessel drifts ashore. a time when salvage vessels were few. as a remedy to pull them away from the loading point in an emergency. There was no requirement for a strong point or how to fit the towing cable to the vessel. but left its application to the member Class Societies. with recommendations on strength. and are only applicable to smaller vessels with a low equipment number. the deadline was set at their first scheduled docking after 1st January 1996. From 1994 DnV’s rules concerning towings cables operated as a guidance only. construction and size.com Capt. adopted on 20th May 1994. The historical background to this cable is long forgotten. 34 Prepared By: SREEKAR REDDY DUPPALLI arrangement at both ends of the ship. the so-called "insurance cable" or "towing cable". Class societies gradually relaxed the requirement for towing cables. On board a powerless vessel the vessel’s own winches are of no use. In 1982 IACS 1 introduced a guidance note on mooring ropes and towing cables. By the end of this year. all tankers above 20. To fasten a towline to a disabled and abandoned vessel in bad weather has always been a very difficult and dangerous operation. Muduli FUN 1 . and such a cable could prove its worth to both underwriters and owners. so did the dimensions of the towing cable. while the forward one has a permitted deployment time of 60 minutes. oil tanker accidents showed that there was a need for a permanently rigged and easy to handle hook-up arrangement to be installed on board the larger vessels. While the "insurance cable" of the old days became obsolete. The requirement for towing facilities on board ships is nothing new. a towing pennant. and of at least 2. but if a chain is used. There are strength requirements for most parts. Such requirements make it necessary not only to strengthen the vessel’s hull at the strong point for the towing attachment. others use two. like bulk carriers and cruise vessels. and represent an added safety and loss preventive factor for all large vessels. The buoys should be fitted with a light to facilitate detection at night. Muduli FUN 1 . The towing pennant is required to have a length of at least twice the lightest seagoing ballast freeboard at the fairlead. a fairlead.000 kN 2 for tankers between 20.000 kN for vessels of greater tonnage. only emergency use. The towing components need to have a working strength of at least 1. and a 30° vertical pull downwards. 35 Prepared By: SREEKAR REDDY DUPPALLI equipment may have to be employed in bad weather and in complete darkness if the vessel is powerless. 2 kN = kilo Newtons. and it is believed that the equipment will prove its worth in years to come. The requirements for the chafing gear allow for different designs. but also at the fairlead point. Opinions have also been voiced in favour of fitting such gear to other large vessels.com Capt. where it is better protected. including a 90° pull to either side. but there is to be a strong point. plus 50 metres. Today emergency towing arrangements are in place on tankers above 20.000 tonnes deadweight. Furthermore. the aft gear is often installed off centre. than the buoy itself. The installations are relatively inexpensive to fit on new vessels. Some owners have preferred to install the gear under deck. Some manufacturers use only one buoy on the pick-up rope. the pick-up gear and the towing pennant are made optional. The emergency towing arrangement at the aft end of the vessel must consist of pick-up gear. a fairlead and a chafing chain. where space is available. Chief Mate’s Oral preparation sreekarduppalli@hptmail. 1 International Association of Classification Societies.000 and 50. the crew is expected to drop the pick-up gear overboard at the stern of the vessel. Before abandoning vessel. At the forward end. it is a particular requirement for the aft arrangement that the pick-up gear can be released manually by one man only. The strength should be sufficient for all relevant angles of the towline. While the forward gear is installed in the vessel’s centreline. chafing gear. Working strength is defined as one half ultimate strength. The gear is therefore not meant for long tows. claiming that it is much easier to get hold of a rope between two buoys.000 tonnes deadweight. a strong point and a roller pedestal. it should be fixed to the strong point and reach at least three meters beyond the fairlead. 36 Prepared By: SREEKAR REDDY DUPPALLI summary of magnetic compass Error Chief Mate’s Oral preparation
[email protected] Capt. Muduli FUN 1 . Muduli FUN 1 . 37 Prepared By: SREEKAR REDDY DUPPALLI Chief Mate’s Oral preparation
[email protected] Capt. you subtract How to calculate variation from compass rose. Muduli FUN 1 . is shown on the compass rose of the chart for that particular locality. points steadily in the general direction of the magnetic north pole. or 5). Multiply that by the amount of annual increase. To find the amount of variation in this locality in1995. 38 Prepared By: SREEKAR REDDY DUPPALLI What are errors of magnetic compass? Errors of magnetic compass:- 1. The variation for any given locality. The amount the needle is offset is called variation because the amount varies at different points on Earth’s surface. Even in the same locality variation usually does not remain constant. No matter which way the ship is heading. if it is a decrease. 2. the magnetic compass. if affected only by variation. VARIATION The true North Pole and the magnetic north pole are not located at the same spot. but increases or decreases at a certain known rate annually. Deviation gradually inc Chief Mate’s Oral preparation sreekarduppalli@hptmail. This variation causes a magnetic compass needle to point more or less away from true north.com Capt. count the number of years since 1990 (in this case 5). add that to the variation in 1990 and you have a 1995 variation of14°50′ W Variation remains the same for any heading of the ship at a given locality. it is not the same on all headings.Although deviation remains a constant for any given compass heading. together with the amount of annual increase or decrease. Remember: If the annual variation is an increase. you add.(which here gives you 5 X 1′. DEVIATION The amount a magnetic compass needle is deflected by magnetic material in the ship is called deviation. decreases. past the correct heading. Muduli FUN 1 . The standard compass provides a means for checking the steering compass and the gyrocompass. and PGC (per gyrocompass). So to roll out on the correct heading one must roll out of the turn.com Capt. Usually the standard compass is topside. and decreases again as the ship goes through an entire 360° of swing. The magnetic steering compass is located in the pilothouse. Courses and bearings by these compasses must be carefully differentiated by the abbreviations PSC (per standard compass). 3. Turning Error A turn from the north lags or indicates a turn in the opposite direction. 39 Prepared By: SREEKAR REDDY DUPPALLI reases. where the magnetic forces producing deviation are not as strong.A turn from the south leads. So to roll out on the correct heading one must roll out of the turn. before reaching the correct heading. where it is affected considerably by deviation. Chief Mate’s Oral preparation sreekarduppalli@hptmail. PSTGC (per steering compass). increases. 6. REMEMBER: ACCELERATE NORTH & DECELERATE SOUTH and THERE IS NO TURNING ERROR ON A EAST OR WEST HEADING. Muduli FUN 1 . The compass card is designed to operate in the horizontal. and any decrease in airspeed (deceleration) will cause the magnetic compass to indicate a false turn toward the south. Chief Mate’s Oral preparation sreekarduppalli@hptmail. use the average indication between the swings. any increase in airspeed (Acceleration) will cause the magnetic compass to indicate a false turn toward the north. 5. Dip is greatest near the poles and least near the Magnetic Equator. and it results in the compass card swinging back and forth around the heading being flown. When setting the gyroscopic heading indicator to agree with the magnetic compass. Oscillation Error This error is caused by turbulence or rough control movements and results in erratic movement of the compass card. 4. Oscillation is a combination of all of the other errors. any movement from the horizontal plane introduces dip error. Magnetic dip Error Magnetic dip is the tendency of the compass needles to point down as well as to the magnetic pole. therefore. 40 Prepared By: SREEKAR REDDY DUPPALLI REMEMBER: THE SOUTH LEADS AND THE NORTH LAGS and THERE IS NO ACCELERATION / DECELERATION ERROR ON A NORTH OR SOUTH HEADING.com Capt. Acceleration and Deceleration Error When on an east or west heading. com Capt. When making a turn from a northerly heading. 41 Prepared By: SREEKAR REDDY DUPPALLI The needle of your magnetic compass will be parallel with Earth’s surface at the Magnetic Equator. and downward when decelerating during airspeed changes. IMO’s Polar Code Enters Into Force – Mandatory For Arctic And Antarctic Waters Chief Mate’s Oral preparation sreekarduppalli@hptmail. when the aircraft turns. the vertical component of the Earth’s magnetic field causes the north- seeking ends of the compass to dip to the low side of the turn. the compass briefly gives an indication of a turn in the opposite direction. Northerly turning error is due to the mounting of the compass. the aft end of the compass card is tilted upward when accelerating. Muduli FUN 1 . While the card is banked. the error indicates a turn to the north. When decelerating on an east or west heading the error is toward the south. Acceleration error is also due to the dip of the Earth’s magnetic field. When accelerating on an east or west heading. This error is most pronounced on an east / west heading. Since the card is balanced in fluid. the card is also banked as a result of centrifugal force. When making a turn from the south. but will point increasing downward as it is moved closer to the Magnetic Pole. it gives an indication of a turn in the correct direction but at a faster rate. Because of the way the compass card is mounted. In the Arctic. The mandatory Polar Code. sewage. And when ice is present. Protective thermal clothing. garbage. It will also provide a strong regime to minimise the impact of shipping operations on the pristine polar regions. Extreme cold may reduce the effectiveness of numerous components of the ship. operational. communication systems and other navigational aids pose challenges for mariners. and all tankers under the Code will have to have double hulls. commercial shipping can make significant reductions in voyage distances between Europe and the Far East by sailing northern routes. go above and beyond those of existing IMO conventions such as MARPOL and SOLAS. which were specifically tailored for the polar environments. helping to protect the lives of crews and passengers. From an environmental perspective. marking a historic milestone in the work of the International Maritime Organization (IMO) to address this key issue. enclosed lifeboats and the ability to ensure visibility in ice. while both the Arctic and Antarctic are becoming increasingly popular tourist destinations. IMO has moved to address international concern about the protection of the polar environment and the safety of seafarers and passengers with the introduction of new regulations that all ships operating in these harsh and challenging waters must comply with. freezing rain and snow conditions are among the Code’s mandatory safety requirements. for ships operating in Arctic and Antarctic waters. Its requirements. food wastes and many other substances. ice removal equipment. training and environmental protection matters that apply to ships operating in the inhospitable waters surrounding the two poles. And if accidents do occur. Muduli FUN 1 . The regulations extend to the materials used to build ships intended for polar operation. It will be seen as a major achievement in IMO’s work Chief Mate’s Oral preparation sreekarduppalli@hptmail. The Polar Code will make operating in these waters safer. which are applicable globally and will still apply to shipping in polar waters. chemicals. Trends and forecasts indicate that polar shipping will grow and diversify over the coming years. To address all these issues. equipment. the remoteness of the areas makes rescue or clean-up operations difficult and costly. construction. it can impose additional loads on the hull and propulsion system. These challenges need to be met without compromising either safety of life at sea or the sustainability of the polar environments. 42 Prepared By: SREEKAR REDDY DUPPALLI With more and more ships navigating in polar waters. Ships operating in the polar regions face a number of unique risks.com Capt. the Polar Code sets out mandatory standards that cover the full range of design. enters into force on 1 January 2017. Poor weather conditions and the relative lack of good charts. the code prohibits or strictly limits discharges of oil. including deck machinery and emergency equipment. Before receiving a certificate. Operator. which may include old ice inclusions • Category C – a ship designed to operate in open water or in ice conditions less severe than those included in categories A and B. The chapters in the Code set out goals and functional requirements specifically covering: ship structure. The Code will require ships intending to operate in the defined Arctic waters and the Antarctic area to apply for a Polar Ship Certificate. to provide the Owner. which would classify the vessel as either: • Category A – ships designed for operation in polar waters in at least medium first-year ice. manning and training. including the most challenging and difficult. prevention of pollution by sewage from ships. stability and subdivision. after 1 January 2018. 43 Prepared By: SREEKAR REDDY DUPPALLI to promote safe and sustainable shipping in all regions of the world. prevention of pollution by harmful substances carried by sea in packaged form. a ship would require an assessment. prevention of pollution by oil. voyage planning. and prevention of pollution by garbage from ships. taking into account the anticipated range of operating and environmental conditions and hazards it may encounter in the polar waters. whichever occurs first. fire safety/protection. safety of navigation. watertight and weathertight integrity. Muduli FUN 1 . designed for operation in polar waters in at least thin first-year ice.com Capt. Technical background The Polar Code includes mandatory provisions covering safety measures (part I-A) and pollution prevention measures (part II-A) and additional guidance regarding the provisions for both (parts I-B and II-B). which may include old ice inclusions • Category B – a ship not included in category A. communications. control of pollution by noxious liquid substances in bulk. Ships constructed before 1 January 2017 will be required to meet the relevant requirements of the Polar Code by the first intermediate or renewal survey. The environmental provisions of the Polar Code apply both to existing ships and new ships. Master and crew with sufficient information regarding the ship’s operational capabilities and limitations in order to support their decision-making process. Ships will need to carry a Polar Water Operational Manual. life-saving appliances and arrangements. The safety provisions of the Polar Code will apply to new ships constructed after 1 January 2017. machinery installations. Chief Mate’s Oral preparation sreekarduppalli@hptmail. prevention of pollution (both oil and noxious liquid substances). after 1 January 2018. Polar Ship Certificate Chief Mate’s Oral preparation sreekarduppalli@hptmail. the environmental provisions and MARPOL amendments were adopted during the 68th session of the MarineEnvironment Protection Committee (MEPC) in May 2015. safety of navigation. life-saving appliances and arrangements.com Capt. manning and training. constructed before 1 January 2017 will be required to meet the relevant requirements of the Polar Code by the first intermediate or renewal survey. communications. watertight and weather tight integrity. Muduli FUN 1 . New mandatory regulations for vessels operating in polar waters An international framework . prevention of pollution from sewage from ships. Training requirements Mandatory minimum requirements for the training and qualifications of masters and deck officers on ships operating in polar waters were adopted by IMO’s Maritime Safety Committee in November 2016. the Polar Code does not apply to fishing vessels. operational safety. 44 Prepared By: SREEKAR REDDY DUPPALLI The Polar Code and SOLAS amendments were adopted during the 94th session of IMO’s Maritime Safety Committee (MSC). voyage planning. Ships. stability and subdivision. and prevention of pollution by discharge of garbage from ships. Certification and Watchkeeping for Seafarers (STCW) and its related STCW Code from 1 July 2018. The Polar Code will be implemented as amendments to MARPOL. vessels under 500 tonnes or fixed structures The code contains comprehensive detailed requirements in separate chapters about ship structure. They will become mandatory under the International Convention on Standards of Training. fire safety/protection. Introduction After intense work and negotiations within the International Maritime Organization (IMO) the International Code for Ships Operating in Polar Waters (the Polar Code) is expected to enter into force on 1 January 2017. in November 2014.the Polar Code – is expected to enter into force in 2017 to protect the Arctic and Antarctic from maritime risks. whichever occurs first. as defined by the Polar Code. SOLAS and the STCW Conventions and will apply to new ships constructed after that date. machinery installations. However. to apply for a Polar Ship Certificate. which is a temperature specified for a vessel that must be set at least 10 degrees Celsius below the lowest mean daily low temperature for the relevant area and season. The issuance of the certificate requires an assessment by the vessel’s flag state/class about identified operational limitations and plans or procedures or additional safety equipment necessary to mitigate incidents with potential safety and/or environmental consequences. Many provisions of the Polar Code are related to the category of the vessel. The manual will provide the Master and crew with information regarding the ship’s operational capabilities and limitations. The cost of carrying out wreck removals continues to escalate and the further complicating factors in polar waters may create challenges for the international insurance and re-insurance markets. a wreck removal or pollution response in non-polar waters. As a leading marine insurer Gard has a responsibility to fully evaluate all and any risks of Arctic and Antarctic activities. B or C vessel. Polar Waters Operational Manual The Polar Code can be seen as a proactive regulation. Polar Operational Limit Assessment Risk Indexing System (Polaris) Chief Mate’s Oral preparation sreekarduppalli@hptmail. The assessment may contain information about low ambient air temperature. Risk evaluation of polar operations These mandatory regulations and standardised approaches are expected to make polar operations safer for operators. systems and equipment required by the Polar Code must function at the polar service temperature. for example. due to the unique challenges posed by the location and the environment. 45 Prepared By: SREEKAR REDDY DUPPALLI The Polar Code will require vessels intending to operate in polar waters. high latitude. For vessels operating in low ambient air temperatures. possibilities of abandoning the ship. Muduli FUN 1 .com Capt. aiming at mitigating the risks of operating in polar waters requiring any vessel sailing in Polar waters to carry a Polar Waters Operational Manual. ice. Operational predictability is closely linked to the ability to price the risk of polar operations at a correct level. remoteness etc. seafarers and more predictable for insurers. It seems likely that a major incident in polar waters would cost more than. As outlined in previous Insight articles it is no secret that the polar environment imposes new and unknown challenges on all operators within the industry. based on the assessment done to issue the Polar Ship Certificate. The Polar Ship Certificate will classify the vessel as either a Category A. Depending on whether the claim is poolable within the International Group or not the loss would fall either on the International Group’s reinsurance programme or if outside the pool on the commercial market. In high latitudes. These are consideration of the uncommon projections used and the accuracy of the surveys.) Mariners prefer using a Mercator chart. Operators intending to operate vessels in the polar waters will need to be familiar with Polaris in addition to existing systems such as the Canadian Arctic Ice Regime Shipping System known as the AIRSS system. The direction that is chosen as the reference for the grid is north. usually the Greenwich meridian. guidelines to the Polar Code have now been introduced to help solve these issues. (This would appear like a bicycle wheel with the pole as the hub. If a magnetic compass is used to follow the grid direction then the corrections of variation and convergency can be combined to a single correction called grid variation or grivation. This section discusses some of the effects and limitations on charts and instruments used in the Arctic. This system is known as the Polar Operational Limit Assessment Risk Indexing System (Polaris) and Gard has been involved in its development. Muduli FUN 1 .com Capt. 4.5. Because the meridians cross all grid lines at the same angle they are fictitious rhumb lines. so then all parallel grid lines can be taken to be extending in the same direction. Projections Chief Mate’s Oral preparation sreekarduppalli@hptmail. so to preserve the look of a Mercator chart a polar grid is used. The direction relative to the grid lines is then known as the grid direction. A grid is printed parallel to a meridian. On a Transverse Mercator chart the fictitious meridians found on this type of chart would serve this purpose.1 Charts There are two areas of concern with the use of charts in the Arctic. The remoteness of the Arctic and the proximity to the North Magnetic Pole has an affect on the charts that are supplied and the navigation instruments that are used with them. 46 Prepared By: SREEKAR REDDY DUPPALLI To date there are some concerns that the Polar Code does not take into account that conditions in the Arctic are never uniform and does not clearly link the ice-classes of vessels with the actual ice conditions prevailing in the polar regions However. The operator is now obliged to explain the methodology used to determine how the ship will be able to operate in the conditions of the planned voyage. Principles of High Latitude Navigation Navigating in high latitudes requires great care in the procedures and in the use of information. the meridians are not the familiar parallel lines of the Mercator chart but radial lines converging at the poles. but other projections such as Lambert Conformal. Precautions to be taken when using charts for Arctic areas include: checking the projection and its limitations. checking the date of survey and / or the Source Classification Diagram. the habit developed with Mercator charts is to use the latitude scale for distance. and the approaches to Polaris and Nanisivik mines. CHECK THE CHART PROJECTION BEFORE USE. Even new editions of charts may be misleading as some information on them may be dated. As the latitude increases the use of rhumb lines for visual bearings becomes awkward. and checking for the method of measuring distances and taking bearings. Polyconic. As the Arctic becomes better surveyed there will be more Mercator charts. such as Lancaster Sound. as a convergency correction may be needed even for visual bearings. Mercator projections suffer too much distortion in the latitude direction to be used for anything but large-scale charts. Barrow Strait. 47 Prepared By: SREEKAR REDDY DUPPALLI To compensate for the fact that the meridians converge as they near the pole the scale of the parallels is gradually distorted. WARNING: IN THE ARCTIC. The more frequently travelled areas. which is not possible on Polyconic charts. to check the type and any cautions concerning distances. using range and bearing to transfer positions from chart to chart. checking for evidence of reconnaissance soundings. etc. Accuracy The accuracy of charts in the Arctic can vary widely according to the date of survey. In the high Arctic. when changing charts. Production priorities may result in new information being added to large-scale charts only. AS IN ANY OTHER AREA. Polar Stereographic is becoming the most popular as it provides minimum distortion over relatively large areas. The number of different projections make it important. Muduli FUN 1 . Particular care must also be taken when laying off bearings in high latitudes. The appearance of depth contour lines on new charts does not indicate any new information.com Capt. Chief Mate’s Oral preparation sreekarduppalli@hptmail. using the larger scale map in preference to the smaller scale map. as it is necessary to add ever larger convergency corrections. but many charts are based on aerial photography (controlled by ground triangulation) combined with lines of reconnaissance soundings. bearings. and Polar Stereographic are used as well. are well surveyed. For example. bottom composition.3 Effect of High Latitude on Compasses and Electronic Aids Compasses The magnetic compass can be erratic in the Arctic and is frequently of little use for navigation: "The magnetic compass depends on its directive force upon the horizontal component of the magnetic field of the earth. For bathymetry (depth soundings. There are 49 charts that specify that positioning with GPS can lead to positioning errors up to some defined magnitude. 4. p. 1982. If you are navigating on a NAD 83 chart with GPS there would be no corrections to apply. Muduli FUN 1 .5. Much of the data has been collected by random vessel’s track soundings or over ice spot soundings.5. Vol. the greater the problem will become. modern standards. The remaining 141 charts did not have any information about the horizontal datum of the chart.GLONASS).2 Canadian Arctic Nautical Charts and Charting Deficiencies One of the principal problems with charts in the Arctic concerns the horizontal datum on which the actual chart is based. In 1997 there were 245 charts listed in the Arctic Chart Catalogue. Regarding GPS. which requires a chart base relative to the NAD 83 horizontal datum. the horizontal component becomes progressively weaker until at some point the magnetic compass becomes useless as a direction measuring device. Additional information may be found in the Annual Edition Notices To Mariners. Canadian Arctic. 48 Prepared By: SREEKAR REDDY DUPPALLI 4. the positions are referenced to the World Geodetic System (WGS 84) which is virtually equivalent to the North American Datum 1983 (NAD 83). which may be as much as 4 nautical miles. As the north magnetic pole is approached in the Arctic. 1.8) Mariners should proceed with due caution and prudent seamanship when navigating in the Arctic especially in poorly charted areas or when planning voyages along new routes.com Capt. If you wanted to plot on a NAD 27 chart you must manually apply the appropriate corrections.) it is estimated by the Canadian Hydrographic Service that less than 25% of the Arctic waters are surveyed to acceptable. etc. (Navigation Instruction. With more and more vessels using accurate positioning systems such as the Global Positioning System (GPS) or the Russian system (Global’naya Navigatsionnaya Sputnikovaya Sistem . Only 55 charts (22%) have sufficient accuracy or detail to facilitate accurate plotting of positions obtained by GPS. THE VALUE OF A CHART DEPENDS TO A GREAT EXTENT ON THE ACCURACY AND DETAIL OF THE SURVEYS ON WHICH IT WAS BASED." Chief Mate’s Oral preparation sreekarduppalli@hptmail. it becomes unusable. by azimuth or amplitude. Radar In general. if performed with caution. Fixes using both sides of a channel or lines from two different Chief Mate’s Oral preparation
[email protected] Capt. Occasionally weather conditions may cause ducting. Even with the compensation given by the latitude corrector on certain makes of compass. ice piled up on the shore or fast ice may obscure the coastline. Muduli FUN 1 . North of 70oN special care must be taken in checking its accuracy. reference must be made to the variation curve or rose on the chart. 49 Prepared By: SREEKAR REDDY DUPPALLI If the compass must be used the error should be checked frequently by celestial observation and. This effect may shorten or lengthen target detection ranges. Low relief in some parts of the Arctic make it hard to identify landmarks or points of land. The gyro compass is as reliable in the Arctic as it is in more southerly latitudes. such as electronic position fixing devices. and even some of the more recently produced charts are based on aerial photography. and the gyro error should be checked whenever atmospheric conditions allow. where course history could be compared with course steered (allowing for wind and current). which is the bending of the radar beam because of a decline in moisture content in the atmosphere. Arctic or cold conditions do not affect the performance of radar systems. For this reason radar bearings or ranges should be treated with more caution than measurements in southern waters. to a latitude of about 70oN. Therefore. To decrease the possibility of errors. A real problem with radar in the Arctic concerns interpretation of the screen for purposes of position fixing. depending on the severity and direction of the bending. Additionally. The numerous alterations in course and speed and collisions with ice can have an adverse effect on its accuracy. Large areas of the Arctic have not yet been surveyed to the same standards as areas further south. or less preferably bearings) should always be used for positions. Position Fixing Problems encountered with position fixing arise from either mistaken identification of shore features or inaccurate surveys. as the rate of change of variation increases as the pole is approached. the gyro continues to lose horizontal force until. The manual for the gyro compass should be consulted before entering higher latitudes. when navigating in the Arctic: the ship's position should be cross-checked with other navigation systems. Visual observations are always preferable. north of about 85°N. Sometimes it is possible to fix the position of grounded icebergs and then to use the iceberg for positioning further along the track. three lines (range. 560 kilometres (about 10. the satellites would be in a constellation around the ship with the receiver actually calculating the ship’s Horizontal Dilution of Precision (HDOP) with satellites possibly on the other side of the pole. 95% of the time. such as electronic positioning systems. position and time data which is received and processed by GPS receivers to determine the user’s three-dimensional position (latitude. For a ship at a position 55° North or South latitude or closer to the pole. and a Precise Positioning Service (PPS) primarily intended for the use of the U.a Standard Positioning Service (SPS) for general public use. the US Department of Defense. consequently degrading the accuracy to those given for SPS. sea or in the air. GPS was declared initially operational in December 1993 with full operational capability being declared in July 1995. the positional accuracy all over the globe is generally considered consistent at the 100 metre level.S. is a space-based radio-navigation system which permits users with suitable receivers. Global Positioning System (GPS) The Global Positioning System. The orbital planes are inclined at 55 o to the plane of the equator and the orbital period is approximately 12 hours. However. to establish their position. The satellites continuously transmit ranging signals. The navigational system consists nominally of 24 operational satellites in six orbital planes. on land. Because of potential problems. altitude). Chief Mate’s Oral preparation sreekarduppalli@hptmail. deemed ‘spares’. This satellite constellation allows a receiver on earth to receive multiple signals from a number of satellites 24 hours a day. The US president has proclaimed that the level of SA will be reduced to zero within the next seven years and when this occurs the horizontal position accuracy for stand alone civilian GPS receivers will improve from the previously stated 100 metre level to the 30 metre level. longitude.com Capt. or GPS. military. in any weather conditions. The SPS point accuracies within 100 metres in the horizontal plane and 156 metres in the vertical plane. though controlled manner. 21 are considered fully operable and the remaining 3 although functioning. speed and time at any time of the day or night. GPS provides two levels of service . deliberately introduced errors in the satellite’s clock oscillator frequency in a seemingly random. velocity and time.900 nautical miles above the earth). The exception to this is the vertical component of a position which will grow weaker the further north a ships sails because above 55 oN there will not be satellites orbiting directly overhead. Of the 24 satellites. 50 Prepared By: SREEKAR REDDY DUPPALLI survey areas should be avoided. fixes in the Arctic should always be compared with other information sources. With a ship at or near the north pole all the satellites would be to the south. but well distributed in azimuth creating a strong fix. This deliberate introduction of errors is known as Selective Availability.1 Although the satellites orbit the earth in a 55 o plane. Muduli FUN 1 . and an orbital radius of 26. Marine Navigation Services. Use of multiple frequencies and relays through other stations are the only methods of avoiding such interference. Information on the chart will describe the horizontal datum used for that chart and for those not referenced to NAD 83. This error is minimized by accurate models and calculations performed within the GPS receiver itself. GPS receivers can be programmed to output latitude and longitude based on a variety of stored datums. Muduli FUN 1 . Sunspot activity is on an 11 year cycle and this activity is expected to peak at about the year 2000.com Capt. corrections will be given to convert NAD 83 positions to the datum of the chart. other than line of sight. July 97 and Telephone Interview A User’s Guide to GPS and DGPS CCG. 1 Richard Langley.1 One minor advantage of the drier. polar environment is the efficiency of the receiver to process satellite data. are subject to interference from ionospheric disturbances. 1998 Radios Radio communications in the Arctic. INMARSAT Chief Mate’s Oral preparation sreekarduppalli@hptmail. 1 If the datum used by the GPS receiver in calculating latitude and longitude is different from the datum of the chart in use. The ionospheric refraction in the auroral zone (the same belt in which the aurora borealis / aurora australis phenomena occur) caused by solar and geomagnetic storms will cause some error. In warmer. GPS World. The title block of the chart will describe the horizontal datums used for the chart and will give the corrections to convert from the datum of the chart to NAD 83 and vice versa. Canada. March 1997. August. Whenever communications are established alternative frequencies should be agreed upon before the signal degrades. Ottawa. errors will occur when GPS derived positions are plotted on the chart. 51 Prepared By: SREEKAR REDDY DUPPALLI Other than Selective Availability. there are a variety of sources of error which can introduce inaccuracies into GPS fixes especially in polar regions such as tropospheric delays and ionospheric refraction in the auroral zone. Since 1986 the Canadian Hydrographic Service has converted some CHS charts to NAD 83. The troposphere varies in thickness from less than 9 kilometers over the poles to over 16 kilometers on the equator which can contribute to propagation delays due to the signals being refracted be electromagnetic signal propagation. marine climatic conditions it is more difficult to model a wet atmosphere. MSAT is a Canadian-owned satellite-based network targeted primarily towards mobile users operating in rural and remote areas. called MSAT. facsimile. The 1990 repositioning of the Atlantic West satellite has extended its area of coverage to include most of Lancaster Sound and Barrow Strait. Upon the ship's return to the satellite area of coverage there may be problems in obtaining the satellite signal and keeping it until the elevation is well above the horizon.com Capt. As the ship leaves the satellite area of coverage the strength of the link with the satellite will become variable. 52 Prepared By: SREEKAR REDDY DUPPALLI Use of INMARSAT services in the Arctic is the same as in the south.8 kbps data processors. 4. electronic mail and voice mail. The MSAT equipment was successfully used from Halifax en route to Resolute. At high latitudes where the altitude of the satellite is only a few degrees above the horizon. and then become unusable. MSAT Mobile Communicators are compact. Currently the initial services include: voice (telephone). When the strength has diminished below that useable for voice communications. and electronic mail of text descriptions of ice conditions from the Canadian Ice Service to the ship. with antennas approximately 20 centimetres high and 20 centimetres in diameter and have been specifically developed for marine applications. the paper facsimile generation of ice charts. gradually decline. signal strength is dependent on the height of the receiving dish and the surrounding land. The equipment and service costs are significantly lower than those charged by international mobile satellite service providers and due to the satellite's optimal geostationary position over the equator. until the ship approaches the edge of the satellite reception. The only weak link has been the dissemination of large graphics files such as SLAR or RADARSAT imagery because they are just too big to be sent through the current 4. it may still be possible to send telexes. MSAT provided a reliable. Important Points for Ice Navigation of Ships Navigating in ice waters can be a real task for ships. MSAT Network upgrades being introduced will include packet-switched communications for applications such as vessel tracking using Global Positioning System technologies. While moving towards subzero temperature with ice Chief Mate’s Oral preparation sreekarduppalli@hptmail. as the later moves cracking and smashing through the frozen and frigid seas. Muduli FUN 1 . efficient and inexpensive method for the reception of ice information in the form of verbal consultation. the Caribbean and 200 nautical miles off the east and west coasts of North America. excellent coverage is available over the Arctic.8 kbps data.A Regional Communications Satellite System Early in 1996 a new telecommunications network. MSAT . Cambridge Bay and Tuktoyaktuk during an evaluation of the satellite's coverage in the 1996 shipping season. dispatch radio. was commercially introduced. an ice pilot and ice breakers are normally provided for commercial vessel operations which help to safely guide the vessels through the ice field to and from their destinations. even the most powerful of the icebreakers have problems with ice navigation. However. If the ship is stopped by heavy concentration of ice the rudder should be put amidships and the engines should be kept turning slowly ahead. the vessel’s speed can be increased so as to maintain headway and control so as to never lose all way off and avoid the ice floes to close in on the hull. In a close pack during ice navigation. The sea-ice. Full rudder movements should be avoided or used only in cases of emergencies. 53 Prepared By: SREEKAR REDDY DUPPALLI covered waters. rudder and propeller.com Capt. Most merchant ships and fishing vessels which are not ice-strengthened must consequently keep away from all ice waters and sub-temperature areas. where the concentration of ice is maximum and the ice pressure is highest. the ship’s captain has to be extremely cautious and must pay utmost attention to the type of ice. can be pierced only by specially designed ice-strengthened vessels or icebreakers with an appropriate ice class. Entry in ice should always be done at low speeds to avoid any sort of damage. a few other measures must be kept in mind by the vessel’s crew during the ice navigation. In many places. Once into the pack. and its exact location in the subzero navigation areas. To avoid such mishaps during ice navigation. Manoeuvring in Ice First of all. ice water should be avoided at all costs. In addition to the ice pilot being on board and the ice-breaker’s relentless assistance. If there’s any kind of misjudgment during ice navigation. Muduli FUN 1 . 1. While manoeuvring through ice if a floe cannot be avoided then it should be hit squarely with the stem. avoid sharp alterations of course and keep the speed enough for steerage way. This will wash away the ice that is accumulated astern and will help the vessel to fall back. Chief Mate’s Oral preparation sreekarduppalli@hptmail. which on an average is 2–3 m thick. if ice navigation is inevitable. it is imperative to understand that if any alternative route is available for the ship. thickness. a detour from the navigable route would lead to additional fuel wastage and might also get the vessel stuck in thick ice leading to dangerous situation and damage. The existence of ice on seawater corresponds to a major restraint for ships and offshore operations at high latitudes in both the hemispheres. it should be made at right angles to the leeward edge where the ice is loose or broken. Note that a glancing blow may damage the ship’s shell plating or throw the vessel off course causing another unavoidable blow. In such cases. to make sure that the bridge is informed immediately in case the propeller is in any kind of danger. engine movements from ahead to astern and vice-verse should be made cautiously to avoid stressing the engine mechanisms in low temperatures. The vessel should keep her engines running with propeller on low RPM so as to avoid seizure by ice. vessels with single screws should have their aft peak tank filled with water and have it kept warm by means of steam hose injection. At nights. Reduce speed if the ice goes under the ship. anchoring can be carried out and it must be done in Chief Mate’s Oral preparation sreekarduppalli@hptmail. Muduli FUN 1 . Anchoring Anchoring in heavy concentrations of ice should be avoided. 4. 5. It is preferred to “heave to” since the leads or lanes cannot be seen. When conditions permit. seawater lubricated tail end shafts are in the danger of getting frozen. avoid navigating through ice at night. Navigation at Night As far as possible. Engine care During ice navigation. Lookout Always keep vigilant lookout for leads (navigable channel within an ice field) through ice. etc. To avoid from freezing. Conning should be carried out from the ship’s bridge to get a better view of the ice accumulation. Similarly. Most ice navigators stop the vessel along the edge of the ice and leave the vessel drifting along with the pack. Additional lookouts should be posted forward or at higher ends for safety concerns. This is extremely important in twin screw vessels. if ice is moving then its force may break the cable. engines should be kept running at all times and under maneuvering conditions in such a way that the ahead and astern movements can be easily carried out without time delay. 3. or other alternative means. walkie-talkies. when ice approaches the stern of the vessel while maneuvering bursts of the engines should be given accordingly to keep ice from accumulating. whistles. 54 Prepared By: SREEKAR REDDY DUPPALLI 2. Keep in mind that at all times the stern must be observed for rudders’ movement so as to avoid a floe from actually moving the stern towards it. it is advised to post men right aft with torches.com Capt. Also. which could be unfavorable to the ship’s engine parts. 30 years for Saturn). infra-red images. the conditions under which these surveys have been carried out are such that their accuracy is unlikely to be similar to that of work done in more clement dimes. slowly spiralling for three months to a maximum altitude of 23° 27′ and then decreasing in altitude until it sets again three months later. as they are known in the temperate regions. and satellite images for a larger view of the surroundings around the vessel. and utmost care must be taken while navigating through such ice areas Polar Environments In high latitudes. so that contrasts vanish and neither the horizon nor surface features can be distinguished. Even then. Using Polar Charts Polar charts are baled largely on aerial photography which may be without proper ground control. directions change fast with movement of the observer. in the approaches to bases and similar frequented localities. add to the difficulties of navigation. The Moon rises once each month and provides illumination when full. In general soundings. it is vital to understand that ship’s operations of any sort under the influence of sea-ice are not only dangerous but also life threatening. 55 Prepared By: SREEKAR REDDY DUPPALLI light brash ice. At the poles the sun rises and sets once a year. when daylight is diffused by multiple reflection between a snow surface and an overcast sky. Chief Mate’s Oral preparation sreekarduppalli@hptmail. Near the poles. e. All time zones meet at the poles. topography and all navigational information are sparse in most polar regions. are quite different in polar regions. except in a relatively few places where modern surveys are available. and the planets rise and set once each sidereal period (12 years for Jupiter. Sunrise and sunset. combined with the ice itself. meridians converge. considerable errors may accumulate when they are separated by appreciable distances. Muduli FUN 1 . Even with the advent of new techniques and technologies for ice navigation such as radar sensor images through cloud cover. even when they are correctly placed relative to adjacent features. Anchor should be brought in as soon as the wind threatens to move ice onto the vessel. Fog is most frequent when the water is partly clear of ice. and local time has little significance. All these conditions. rotten ice or widely scattered floes with the main engine on immediate notice.g. Low cloud ceilings are prevalent. and excessive longitudinal curvature renders the meridians and parallels impracticable for use as navigational references. though sometimes the aurora (gives even more light.com Capt. ‘Whiteouts’ occur from time to time. For these reasons the geographical positions of features may be unreliable and. night and day. though in many parts of the polar regions depths change too abruptly to enable the Mariner to rely solely on the sounder for warning.com Capt. provided that the ship has been swung and the compass adjusted in low latitudes. the ship should be slowed to obtain a sounding. unless of observed objects which are close. Using Compasses The gyro compass losses all horizontal directive force as the poles are approached and is thought to become useless at about 85° of latitude. Along many of these coasts the various points and inlets bear a marked resemblance to each other. so. It is generally reliable up to 70° but thereafter should be checked by azimuths of celestial bodies at frequent intervals (about every 4 hours and more frequently in higher latitudes). The magnetic compass is of little value for navigation near the magnetic poles. If used on a Mercator chart. 56 Prepared By: SREEKAR REDDY DUPPALLI Visual and radar bearings. but their usefulness is restricted by the difficulty in identifying them. however. Working in drift ice the echo sounder trace may be lost due to ice under the ship or hull noises. Learning to Listen to Sounders The echo sounder should be run continuously to detect signs of approaching shoal water. or of the drift of the ice. Being Observant Chief Mate’s Oral preparation sreekarduppalli@hptmail. or locating them on the chart. have been reported. The appearance of a coast is often very different when many of its features are marked by a heavy covering of snow or ice than when it is ice-free. and in these areas ships should make use of all enforced stops to obtain a sounding. if necessary. bearings should be corrected for half-convergency in the same way as radio bearings. attributed to the continual motion of the poles. the magnetic compass can be used. the depths may give an indication of the ship’s position. In some better sounded areas. Frequent comparisons of magnetic and gyro compasses should be made and logged when azimuth checks are obtained. Natural landmarks are plentiful in some areas. In other parts of the polar regions. Muduli FUN 1 . Large diurnal changes in variation (as much as 10°). Frequent changes of course and speed and the impact of the vessel on ice introduce errors which are slow to settle out. and again on entering high ones. require to be treated as great circles. the accuracy of the resulting positions must always be questioned. The angle C is the difference between the longitudes of A and B. 57 Prepared By: SREEKAR REDDY DUPPALLI The Mariner cannot rely on obtaining accurate celestial observations. As the latitude increases twilights lengthen. in particular side c (the great-circle distance) and angle A (the initial course). b. In polar regions the only celestial body available for observations may not exceed the altitude of 10° for several weeks on end. and C. B. C. The length of a great- circle arc can be read off immediately from the corresponding central angle: the measurement of the central angle in minutes of arc gives the length of the arc in nautical miles. a great circle.com Capt. The best positions are usually obtained from star observations during twilight. but with this increase come longer periods when the sun is just below the horizon and the stars have not yet appeared. Most celestial observations in polar regions produce satisfactory results. The points A and B form a spherical triangle with the North Pole C. Chief Mate’s Oral preparation sreekarduppalli@hptmail. apart from the moon at times. i. Side a has length 90o minus the latitude of vertex B. then in this triangle we know a. If we call a. and as accurate dead reckoning in ice is impossible. b. Muduli FUN 1 . observations at low altitudes must be accepted. and vice-versa. but in high latitudes the navigator should be on the alert for abnormal conditions. Great circle sailing The calculation of the great circle track between two points A and B with given latitude and longitude is an exercise in spherical trigonometry. Each side of this triangle is an arc of a circle centered at the center of the earth. c the sides opposite vertices A. transferred position lines must be used. This is enough information to solve for all the elements of the triangle.e. contrary to the usual practice. In summer when. so that. and long days and short nights in summer preclude the use of stars for observations. For much of the navigational season clouds hide the sun. only the sun can be used for observations. because the ship keeps to the same course through the whole trip. 123o-04'W. and C this gives A = 57.77o. Long... We may solve for c using the spherical law of cosines: cos c = cos a cos b + sin a sin b cos C.36o or 4461. In this case we compute a = 90o . c. 37 o-42' N.34o50' = 55o10' and C = 360o - 123o04' . near Farallon Island Lighthouse. near the entrance to the Bay of Tokio. form a spherical triangle. 139o-53' E. to a point Lat. together with the North Pole. Muduli FUN 1 .37o42' = 52o18'. Chief Mate’s Oral preparation sreekarduppalli@hptmail. Long.com Capt. and the path of shortest length between two points on a sphere is the great-circle arc between them. 34 o-50' N. b = 90o ..139o53' = 97o03'. The earth's surface is (to a good approximation) a sphere. 58 Prepared By: SREEKAR REDDY DUPPALLI Starting point and destination. The great circle in question is the intersection of the spherical surface with the plane passing through the two points and the center of the earth. Using the known values for a. or 57o46'19". when measured back on the earth's surface. Its disadvantage is that the straight line on a Mercator map may not be the shortest path between its endpoints. The great-circle track The rhumb-line track is very convenient.6 nautical miles. Here is the problem from Dutton: Compute the distance and initial course by great circle sailing from a point in Lat. A can be calculated using the spherical law of sines: sin A / sin a = sin B / sin b = sin C /sin c. Once c is known.. This gives c = 74. 7 nautical miles. 123o-04'W. Long. to a point Lat. Chart Projections The surface of the Earth is a sphere and charts are flat surfaces. If the points are nearby.. say within 50 miles of each other. 139o-53' E. 37 o-42' N. But for distant points the difference may be substantial..meeting a curve or surface in a single point if a sufficiently small interval is considered. Plane . Map Projection . Compute the distance and initial course by great circle sailing from a point in Lat.a surface of such nature that a strait line joining 2 of its points lies wholly in the surface (a flat surface). taken from Benjamin Dutton's "Navigation and Nautical Astronomy. the chart maker must flatten out the surface of the Earth to put it on a plane. Answer: distance = 4461.com Capt. Long.. a text once used at Annapolis. the difference between the two paths is inconsequential. Muduli FUN 1 . Terms we must know before learning the types of projections: Projection . 34 o-50' N. Tangent . 59 Prepared By: SREEKAR REDDY DUPPALLI The great-circle path is different from the rhumb line unless the two points are both on the equator or both on the same meridian. Here is a classic navigation problem. the transfer of a point from one surface to a corresponding position on another surface by graphical or analytical means. A map projection may be established by analytical computation or may be constructed geometrically. near the entrance to the Bay of Tokio. The process is known as Chart Projection. In making navigation charts. course = N 57 o46'15"W. It is impossible to transfer the features on a sphere to a flat surface without distorting the features.a systematic drawing of lines on a plane surface to represent the parallels of latitude ant the meridians of longitude of the Earth or a section of the Earth. The chart maker starts with a Developable Surface that is the area of the Earth that can Chief Mate’s Oral preparation sreekarduppalli@hptmail. near Farallon Island Lighthouse..the extension of lines or planes to intersect a given surface." 7th Edition. The cylinder maintains equal diameter throughout so there is distortion as to the diameter of the latitude circles. i. Each method to project the surface of the Earth onto a chart has its own advantages and disadvantages.Preserving the correct shape.Having correct angular representation. Muduli FUN 1 . A projection with correct angular relationship will also have true shape of features so it is conformal & orthomorphic. When choosing the type of chart projection you are going to use for navigation. like harbor charts. Rhumb lines represented as strait lines. Equal area. all the projections are practically identical. the parallels are shown perpendicular to the projected meridians. 60 Prepared By: SREEKAR REDDY DUPPALLI be flattened to form the plane. the meridians converge with increased latitude. On the Earth. Chief Mate’s Oral preparation sreekarduppalli@hptmail. Geometric Mercator Projection Cylindrical Projection A cylinder is placed around the Earth and is tangent to the equator The planes of the meridians are extended & they intersect the cylinder in a number of vertical lines. Great circles represented as strait lines. There are different ways that the surface of the Earth can be flattened to make a chart. or the representation of areas in their correct relative proportions. Orthomorphic . On the larger scale charts. Perspective . Many of these properties are mutually exclusive. Constant scale values for measuring distance. you will be looking for certain desirable properties. the projection is perspective or geometric. These properties are: True shape of physical features Correct angular relationship. The parallel lines of projection (longitude lines) are equidistant from each other unlike the terrestrial meridians. If the points on the surface of the Earth are projected from a single point. The smaller the scale. a chart cannot represent both Rhumb lines and Great Circles as strait lines. On the earth. Conformal . the more noticeable the difference between the different chart projections.e. On the cylinder. the parallels of latitude form circles whose diameter decreases with increasing latitude.how the Earth looks from a certain point of view & is projected onto a plane to create an image on the chart.com Capt. The Meridians and Parallels are represented by strait lines that are perpendicular to each other. The cylinder is tangent along the equator. Muduli FUN 1 . Conformal. constitutes the number of Meridional Parts corresponding to that latitude. stretch the Longitudes so they become the same width apart as they were at the equator and stick them onto the cylinder. expressed in minutes of arc at the equator as a unit.be sure to use the Latitude Scale for the Latitude you are working on or the Mid-Latitude because of the lengthening of the parallels as you go toward the poles. Orthomorphic and proportional. On the Mercator Projection the 60 nm between each minute of Latitude will look like it is much farther as you get away form the equator. 61 Prepared By: SREEKAR REDDY DUPPALLI Most common projection used for navigation is the Mercator projection which is classified as a Cylindrical Projection. Due to the mathematical expansion of the lat. fat Charlie Brown. You can stretch Charlie Brown Top to Bottom and end up with a larger version of the comic you pressed the silly putty to. The ratio is know as Meridional Parts . Next./long uses trig functions (secant) this projection cannot cover the poles.) The easy way to understand this projection is to first put the cylinder around the Earth touching the Equator. Lambert Conformal First you must understand the basic conic projection. The meridians and parallels are expanded at the same ratio with increased latitude. the distortion in the polar regions (above 70N and below 70S) caused by this projection is too great to be used for navigation. The Parallels are spread out as they get away from the equator but in the real world each degree is the same distance apart. Now you have to stretch the Latitude on the Cylinder so that it gets stretched the same amount as the longitude did at a given location. (Used to make Mercator Projections & Mercator Sailings. Conic Projection - Chief Mate’s Oral preparation
[email protected] Capt. It is as if you took silly putty to a Peanut's Comic and stretched Charlie Brown only side to side . Rhumb Lines are drawn strait Great circles are arcs the curve toward the nearest pole. like you would peal a bannana.The length of a meridian. Then cut the Lines of Longitude and peal them away from the Earth starting at the Poles. degrees of Latitude remain approximately the same length & the degrees of Longitude become increasingly shorter on the Earth. As the distance from the equator increases. (Secant for 90 is infinity) Generally. The didtance scale varies. You can use the Latitude Scale to measure distance . The Meridians are now parallel to each other on the cylinder but the shape of the land is distorted.you end up with a short. The projection is perspective . The are between the standard parallels is compressed and the area beyond is expanded. Points along the track then get transfered to a Mercator Projection. Oblique Gnomonic- A tangent plane is placed on the Earth. A conic projection tangent to the equator is actually a cylindrical projection because the height of the vertex of the cone would be near infinity. the land features will be the shadows that shine on the tangent plane. Great Circles draw as strait lines . This actually cuts into the earth. the height of the cone is 0 so the cone becomes a plane. The point at which the cone is tangent. the parallels appear as arcs of circles and the meridians appear as strait or curved lines converging toward the nearest pole. The Meridian will appear as straight lines that converge at the poles as they do on the Earth. If the spacing of the parallels is altered. such that the distortion is the same along them as along the meridians.how the Earth looks from a certain point of view & is projected onto a plane to create an image on the chart. The Chief Mate’s Oral preparation sreekarduppalli@hptmail. 62 Prepared By: SREEKAR REDDY DUPPALLI Points on the surface of the Earth are transferred to a tangent cone. It is not conformal or orthomorphic. the projection becomes conformal. Muduli FUN 1 . This projection is perspective from the center of the Earth.com Capt. This chart is often called a "Great Circle" Chart because its only use is to Plan Great Circle Voyages. At the poles. The points are projected from the center of the Earth to the plane. When the axis of the cone coincides with the axis of the Earth. That is called a Lambert Conformal Projection. Gnomonic Chart Projection A plane is placed tangent to the surface of the Earth. if you take a flashlight at the center of the Earth & shine it in the direction of the tangent plane.these charts are often used for aeronautical charts or used for polar navigation. Great circles plot as straight lines and rhumb lines plot as curves away from the pole. The distance along any meridian between consecutive parallels is in correct relation to the distance on the earth The scale is correct along any meridian and along the Standard Parallel. is know as the standard parallel. there are 2 standard parallels that the cone is tangent to. Basically. Secant Conic or Conic Projection with 2 standard parallels - Like the name says. Muduli FUN 1 . 63 Prepared By: SREEKAR REDDY DUPPALLI Latitude lines.com Capt. will be curved. Cylindrical Projection Chief Mate’s Oral preparation sreekarduppalli@hptmail. except the equator. The loxodrome is a line of constant heading. Oblique gnomonic projection Chief Mate’s Oral preparation sreekarduppalli@hptmail. and the great circle. although appearing longer than the loxodrome. Rhumb line on Mercator Projection Comparison of Great Circle Route and Loxodrome on the Mercator Projection. is actually the shortest route between New York and London. Muduli FUN 1 .com Capt. 64 Prepared By: SREEKAR REDDY DUPPALLI Great Circle vs. 65 Prepared By: SREEKAR REDDY DUPPALLI This tangent plane projection is an Oblique Gnomonic Projection because it is from the perspective of the center of the Earth.com Capt. It is used to pan great circle routes. at theoretical rising or setting. Click Amplitude The Amplitude of a body is the angle at the observer’s zenith or the arc of his rational horizon contained between the observer’s prime vertical and the vertical circle through the body. The gnomonic projection is also know as a "Great Circle" chart because that is really its only use for ocean navigation. Click on the picture to see it in motion! An oblique gonmonic projection in the Southern Hemisphere with a great circle course plotted out. Chief Mate’s Oral preparation sreekarduppalli@hptmail. Muduli FUN 1 . its true altitude should be exactly 0° which implies that its zenith distance will be exactly 90°. Therefore sum of the true rising bearing and true setting bearing is always equal to 360°. as shown in the figure. Amplitude is therefore named from east towards n or s when rising and from west towards n or s when setting and then converted to 360° notation. The mean between the two bearings will therefore always be equal to 180°. Muduli FUN 1 . the amplitude will be southward of e or w When the declination of the sun remains unchanged between rising and setting. and not from the observer’s meridian. For a body with northerly declination. Sin amplitude= sin Dec x sec lat Chief Mate’s Oral preparation sreekarduppalli@hptmail. 66 Prepared By: SREEKAR REDDY DUPPALLI When observing the amplitude of a body. the true amplitude at rising should equal the true amplitude at setting. the amplitude will be northward of e or w and For a body with southerly declination. The difference between 180° and the mean of the two compass bearings will therefore give the error.com Capt. its centre should be on the rational horizon. that is. Amplitude is measured from the observer’s prime vertical. Sin(90-Z) Sin dec = cos lat . sec lat Amplitude Calculation: 1. Muduli FUN 1 .cosZ Sin dec = cos lat . 67 Prepared By: SREEKAR REDDY DUPPALLI Using Napier’s Rule.com Capt. Sin Amp Sin Amp = Sin dec / cos lat Sin Amp = Sin dec . Obtain GMT 2. Obtain declination of body Chief Mate’s Oral preparation sreekarduppalli@hptmail. Sin(90-PX)=cos(90-PZ). IN QUADRANTAL SPHERICAL ∆PZX. 68 Prepared By: SREEKAR REDDY DUPPALLI 3. Calculate amp as per above formula 4. Convert to 360° notation. The amplitude of a rising body and also setting body will be the same for a particular declination for a stationary observer at a particular latitude in the north and also for the same value latitude in the south. What is the "1-2-3 Rule" used for hurricane avoidance? The 1-2-3 Rule is means of avoiding winds associated with a tropical cyclone by taking into account the forecast track error of the National Weather Service over a 10 year period which is approximately 100 nm in 24 hours, 200 nm for 48 hours and 300 nm in 72 hours. The forecast track error is added to the 34 knot wind radii to compute the danger area. The wind radii may be found within Tropical Cyclone Forecast Advisory (TCM) forecasts. For more detailed information on the 1-2-3 Rule, see the National Hurricane Center's Marine Safety Page The National Hurricane Center and Central Pacific Hurricane Center also prepare Atlantic, East Pacific and Central Pacific "Tropical Cyclone Danger Area" charts for broadcast via radiofax, depicting the danger area computed using the 1-2-3 Rule as a basis. The danger area will not be depicted for tropical cyclones that transition to extratropical status. Chief Mate’s Oral preparation
[email protected] Capt. Muduli FUN 1 69 Prepared By: SREEKAR REDDY DUPPALLI MARINE SAFETY ACTIONS Review regional tropical cyclone climatology for area of expected operations. Obtain latest Marine Prediction Center & Tropical Prediction Center analysis/forecast charts; including surface, upper level, & Sea State (wind/wave) charts. Locate & plot tropical (easterly) waves, disturbances, and tropical cyclones. If available, examine current satellite imagery. Obtain latest tropical cyclone advisory messages. Plot current/ forecast positions of all active/ suspected tropical cyclone activity. Plot completed tropical cyclone danger area to avoid chart. Chief Mate’s Oral preparation
[email protected] Capt. Muduli FUN 1 70 Prepared By: SREEKAR REDDY DUPPALLI Determine possible courses of action (at least 2) for vessel to take in order to remain clear of the Danger. Evaluate current/nearby port & hurricane haven locations that may be considered for tropical cyclone avoidance. Calculate Closest Point of Approach (CPA) to tropical cyclone for all courses of action based on latest forecast/ advisory. Make decision on course of action to follow and execute. Continue to closely monitor tropical cyclone's progress and review the actions listed here when new meteorological analysis & forecast information becomes available. 1-2-3 RULE OF THUMB 1 - 100 mile error radius for 24hr forecast 2 - 200 mile error radius for 48hr forecast 3 - 300 mile error radius for 72hr forecast STEPS TO DETERMINE THE HURRICANE DANGER AREA Plot the initial and forecast hurricane positions on a navigation chart. Find the maximum radius of 34 KT winds at the initial, 24, 48, and 72 hour forecast times of the TCM. Apply the 1-2-3 rule to each of the radii at the 24, 48, and 72 hour forecast positions. Draw a circle around the hurricane initial position with radius equal to the maximum radius of 34 KT winds given in the TCM. Draw circles around the 24, 48, and 72 hour forecast positions of the hurricane using the respective radii found in step 3. Connect tangent lines to each circle constructed in steps 3 and 4 along both sides of the hurricane track. The area enclosed by these tangent lines is known as the danger area of the hurricane and must be avoided as a vessel attempts to navigate in the vicinity of the hurricane Chief Mate’s Oral preparation
[email protected] Capt. Muduli FUN 1 Also. a few guidelines should be used by the mariner in order to limit the potential of a close encounter between ship & storm. The 1-2-3 rule establishes a minimum recommended distance to maintain from a hurricane in the Atlantic. It also deserves mention that the state of the sea outside of the radius of 34 KT winds can also be significant enough as to limit course & speed options available to the mariner and must also be considered when avoiding hurricanes. Muduli FUN 1 . The Mariner’s 1-2-3 Rule originally was an adaptation made from a US Navy training film “A Time for All measures” in use during the early 1970′s. 34 KT Rule For vessels at sea. decreased vessel handling. sea state development approaches critical levels resulting in rapidly decreasing limits to ship maneuverability. Understanding & use of this technique should be mandatory for any vessel operating near a hurricane. avoiding the 34 KT wind field of a hurricane is paramount. The rule is derived from the latest 10-year average FTE associated with hurricanes in the North Atlantic. 71 Prepared By: SREEKAR REDDY DUPPALLI Guidelines For Avoiding Hurricanes At Sea In order to help account for the inherent errors in hurricane forecasting. Larger buffer zones should be established in situations with higher forecast uncertainty. Application of the rule requires information from the TCM and is extremely important to remaining clear of a hurricane at sea. limited crew experience. The 34 knot or higher wind Chief Mate’s Oral preparation sreekarduppalli@hptmail. approximately 100 nm for each 24 hour forecast period plus the radius of forecasted gale force (34 knot or higher) winds. the rule does not account for the typical expansion of the wind field as a system transitions from hurricane to extratropical gale/storm. 34 KT is chosen as the critical value because as wind speed increases to this speed. See Marine Safety Rules of Thumb at right for details on applying this most important technique. Since the 1990’s the Mariner’s 1-2-3 Rule has incorporated a “danger zone” by adding the 10-year average tropical cyclone forecast track errors which were at the time. The Mariner’s 1-2-3 Rule was developed as an aid for mariners to avoid tropical cyclones by accounting for forecast track errors and is a must for any mariner to know when navigating near a hurricane or tropical storm. or other factors set by the vessel master. The rule does not account for sudden & rapid intensification of hurricanes that could result in an outward expansion of the 34 KT wind field. 1-2-3 Rule This is the single most important aid in accounting for hurricane forecast track errors (FTE).com Capt. There has been a significant improvement in cyclone track forecasting in recent years and we should now revise the Mariner’s 1-2-3 rule to better reflect this improvement.com Capt.“ Tropical Cyclone Track Errors Chief Mate’s Oral preparation sreekarduppalli@hptmail. Muduli FUN 1 . has vastly improved. then course options are also significantly reduced. 2 degrees (120nm) at 48 hours. 72 Prepared By: SREEKAR REDDY DUPPALLI field was chosen as the critical wind speed because at this level or higher the wind and sea conditions significantly limit ship maneuverability. The 1-2-3 Rule today should include the more accurate skill score data that adds up to about 1 degree of latitude (60nm) at 24 hours. According to Lee Chesneau. owner of Chesneau Marine Weather and former Ocean Prediction Center meteorologist we should consider revising the rule as follows: “The overall skills scores of the NHC for track location which the wind radii extends from. When ship maneuverability is limited. and 3 degrees (180NM) at 72 hours. limited crew experience. then the radius of danger would be 60nm (the 24 hour average track error) plus 120 nm (radius of forecasted gale or higher winds) or a total of 220 nm danger zone left and right of the forecasted track and position. or limits on vessel handling. Muduli FUN 1 . The rule also does not account for sudden & rapid intensification of hurricanes that could result in significant expansion of the 34 KT wind field or to the typical wind field expansion that occurs when a hurricane transitions to an extra-tropical storm. Therefore. Proposed New Mariner's 1-2-3 Rule by Lee Chesneau of Lee Chesneau's Marine Weather Chief Mate’s Oral preparation sreekarduppalli@hptmail. if the 24 hour forecast shows gale (34 knot or higher) winds will extend out to 120 nm. 73 Prepared By: SREEKAR REDDY DUPPALLI For example. Keep in mind that larger safety zones should be considered whenever there is a high degree of forecast uncertainty.com Capt. This then becomes the minimum distance to maintain from the hurricane center in 24 hours. the forecasted radius of gale force (34 knot or higher) wind field is also added. In addition to the allowance for track error. at 24 hours (1 degree of latitude or 60 nm) would be added to the right and left of the track. At 48 hours the error is (2 x 1 degree or 120nm) and for 72 hours the error is (3 x 1 degree or 240nm). and the gyro error should be checked whenever atmospheric conditions allow. as the rate of change of variation increases as the pole is approached. north of about 85°N. Therefore. by azimuth or amplitude. North of 70oN special care must be taken in checking its accuracy. Even with the compensation given by the latitude corrector on certain makes of compass. Occasionally weather conditions may cause ducting. when navigating in the Arctic: the ship's position should be cross-checked with other navigation systems. 74 Prepared By: SREEKAR REDDY DUPPALLI The National Hurricane Center currently produces a “Tropical Cyclone Danger Graphic” depicting the “1-2-3 Rule” danger zone for tropical cyclones in both the North Atlantic and Eastern North Pacific oceans but this graphic still uses the older average track error of 100NM per 24 hours Perhaps it is time for NOAA to update this. the gyro continues to lose horizontal force until. Radar In general.com Capt. As the north magnetic pole is approached in the Arctic. This effect may shorten or lengthen target detection ranges. The gyro compass is as reliable in the Arctic as it is in more southerly latitudes. Effect of High Latitude on Compasses and Electronic Aids Compasses The magnetic compass can be erratic in the Arctic and is frequently of little use for navigation: "The magnetic compass depends on its directive force upon the horizontal component of the magnetic field of the earth. it becomes unusable. the horizontal component becomes progressively weaker until at some point the magnetic compass becomes useless as a direction measuring device. Arctic or cold conditions do not affect the performance of radar systems. where course history could be compared with course steered (allowing for wind and current). depending on the severity and direction of the bending. The manual for the gyro compass should be consulted before entering higher latitudes. which is the bending of the radar beam because of a decline in moisture content in the atmosphere. such as electronic position fixing devices. to a latitude of about 70oN." If the compass must be used the error should be checked frequently by celestial observation and. Muduli FUN 1 . reference must be made to the variation curve or rose on the chart. A Chief Mate’s Oral preparation sreekarduppalli@hptmail. The numerous alterations in course and speed and collisions with ice can have an adverse effect on its accuracy. such as electronic positioning systems. However. The satellites continuously transmit ranging signals. Position Fixing Problems encountered with position fixing arise from either mistaken identification of shore features or inaccurate surveys.560 kilometres (about 10. if performed with caution. Because of potential problems. GPS provides two levels of service . altitude). The navigational system consists nominally of 24 operational satellites in six orbital planes. in any weather conditions. To decrease the possibility of errors. Fixes using both sides of a channel or lines from two different survey areas should be avoided. velocity and time. 95% of the time. Visual observations are always preferable. Of the 24 satellites. is a space-based radio-navigation system which permits users with suitable receivers. Sometimes it is possible to fix the position of grounded icebergs and then to use the iceberg for positioning further along the track. 21 are considered fully operable and the remaining 3 although functioning. 75 Prepared By: SREEKAR REDDY DUPPALLI real problem with radar in the Arctic concerns interpretation of the screen for purposes of position fixing.com Capt. ice piled up on the shore or fast ice may obscure the coastline. speed and time at any time of the day or night.S. or GPS. three lines (range. position and time data which is received and processed by GPS receivers to determine the user’s three-dimensional position (latitude. Global Positioning System (GPS) The Global Positioning System. military. deliberately introduced errors in the satellite’s clock oscillator frequency in a seemingly Chief Mate’s Oral preparation sreekarduppalli@hptmail. The SPS point accuracies within 100 metres in the horizontal plane and 156 metres in the vertical plane. For this reason radar bearings or ranges should be treated with more caution than measurements in southern waters. Low relief in some parts of the Arctic make it hard to identify landmarks or points of land. and even some of the more recently produced charts are based on aerial photography. Muduli FUN 1 . deemed ‘spares’. longitude. and an orbital radius of 26.900 nautical miles above the earth). This satellite constellation allows a receiver on earth to receive multiple signals from a number of satellites 24 hours a day. The orbital planes are inclined at 55 o to the plane of the equator and the orbital period is approximately 12 hours. on land.a Standard Positioning Service (SPS) for general public use. to establish their position. fixes in the Arctic should always be compared with other information sources. or less preferably bearings) should always be used for positions. GPS was declared initially operational in December 1993 with full operational capability being declared in July 1995. the US Department of Defense. sea or in the air. Additionally. and a Precise Positioning Service (PPS) primarily intended for the use of the U. Large areas of the Arctic have not yet been surveyed to the same standards as areas further south. Muduli FUN 1 . the satellites would be in a constellation around the ship with the receiver actually calculating the ship’s Horizontal Dilution of Precision (HDOP) with satellites possibly on the other side of the pole. the positional accuracy all over the globe is generally considered consistent at the 100 metre level. The troposphere varies in thickness from less than 9 kilometers over the poles to over 16 kilometers on the equator which can contribute to propagation delays due to the signals being refracted be electromagnetic signal propagation. Other than Selective Availability. This error is minimized by accurate models and calculations performed within the GPS receiver itself. For a ship at a position 55° North or South latitude or closer to the pole. marine climatic conditions it is more difficult to model a wet atmosphere. though controlled manner. polar environment is the efficiency of the receiver to process satellite data.com Capt.1 One minor advantage of the drier. Sunspot activity is on an 11 year cycle and this activity is expected to peak at about the year 2000. With a ship at or near the north pole all the satellites would be to the south. In warmer. The ionospheric refraction in the auroral zone (the same belt in which the aurora borealis / aurora australis phenomena occur) caused by solar and geomagnetic storms will cause some error. Since 1986 the Canadian Hydrographic Service has converted some CHS charts to NAD 83. The title block of the chart will describe the horizontal datums used for the chart and will give the corrections to convert from the datum of the chart to NAD 83 and vice versa. corrections will be given to convert NAD 83 positions to the datum of the chart. Chief Mate’s Oral preparation sreekarduppalli@hptmail. 76 Prepared By: SREEKAR REDDY DUPPALLI random. consequently degrading the accuracy to those given for SPS. errors will occur when GPS derived positions are plotted on the chart. The US president has proclaimed that the level of SA will be reduced to zero within the next seven years and when this occurs the horizontal position accuracy for stand alone civilian GPS receivers will improve from the previously stated 100 metre level to the 30 metre level. Information on the chart will describe the horizontal datum used for that chart and for those not referenced to NAD 83.1 Although the satellites orbit the earth in a 55 o plane. The exception to this is the vertical component of a position which will grow weaker the further north a ships sails because above 55 oN there will not be satellites orbiting directly overhead. This deliberate introduction of errors is known as Selective Availability. but well distributed in azimuth creating a strong fix. 1 If the datum used by the GPS receiver in calculating latitude and longitude is different from the datum of the chart in use. GPS receivers can be programmed to output latitude and longitude based on a variety of stored datums. there are a variety of sources of error which can introduce inaccuracies into GPS fixes especially in polar regions such as tropospheric delays and ionospheric refraction in the auroral zone. The MSAT equipment was successfully used from Halifax en route to Resolute. Upon the ship's return to the satellite area of coverage there may be problems in obtaining the satellite signal and keeping it until the elevation is well above the horizon. MSAT Mobile Communicators are compact.8 kbps data. the Caribbean and 200 nautical miles off the east and west coasts of North America. Cambridge Bay and Tuktoyaktuk during an evaluation of the satellite's coverage in the 1996 shipping season. electronic mail and voice mail. dispatch radio. INMARSAT Use of INMARSAT services in the Arctic is the same as in the south. As the ship leaves the satellite area of coverage the strength of the link with the satellite will become variable. it may still be possible to send telexes. MSAT . Ottawa. excellent coverage is available over the Arctic. Chief Mate’s Oral preparation sreekarduppalli@hptmail. Canada. Marine Navigation Services. Use of multiple frequencies and relays through other stations are the only methods of avoiding such interference. March 1997. Whenever communications are established alternative frequencies should be agreed upon before the signal degrades. Currently the initial services include: voice (telephone). are subject to interference from ionospheric disturbances. At high latitudes where the altitude of the satellite is only a few degrees above the horizon. gradually decline. with antennas approximately 20 centimetres high and 20 centimetres in diameter and have been specifically developed for marine applications. called MSAT. facsimile. 77 Prepared By: SREEKAR REDDY DUPPALLI 1 Richard Langley. The 1990 repositioning of the Atlantic West satellite has extended its area of coverage to include most of Lancaster Sound and Barrow Strait. until the ship approaches the edge of the satellite reception. and then become unusable. other than line of sight. The equipment and service costs are significantly lower than those charged by international mobile satellite service providers and due to the satellite's optimal geostationary position over the equator. 4. Muduli FUN 1 . was commercially introduced. When the strength has diminished below that useable for voice communications.com Capt. 1998 Radios Radio communications in the Arctic. July 97 and Telephone Interview A User’s Guide to GPS and DGPS CCG. signal strength is dependent on the height of the receiving dish and the surrounding land. GPS World. MSAT is a Canadian-owned satellite-based network targeted primarily towards mobile users operating in rural and remote areas.A Regional Communications Satellite System Early in 1996 a new telecommunications network. August. 8 kbps data processors. or 5). count the number of years since 1990 (in this case 5). The variation for any given locality. is shown on the compass rose of the chart for that particular locality. Multiply that by the amount of annual increase. VARIATION The true North Pole and the magnetic north pole are not located at the same spot. Muduli FUN 1 . MSAT Network upgrades being introduced will include packet-switched communications for applications such as vessel tracking using Global Positioning System technologies. if it is a decrease. Remember: If the annual variation is an increase. but increases or decreases at a certain known rate annually. This variation causes a magnetic compass needle to point more or less away from true north. you subtract How to calculate variation from compass rose. together with the amount of annual increase or decrease. you add.(which here gives you 5 X 1′. The amount the needle is offset is called variation because the amount varies at different points on Earth’s surface. No matter which Chief Mate’s Oral preparation sreekarduppalli@hptmail. 78 Prepared By: SREEKAR REDDY DUPPALLI MSAT provided a reliable. To find the amount of variation in this locality in1995. Errors of magnetic compass:- 1. and electronic mail of text descriptions of ice conditions from the Canadian Ice Service to the ship. the paper facsimile generation of ice charts. Even in the same locality variation usually does not remain constant. The only weak link has been the dissemination of large graphics files such as SLAR or RADARSAT imagery because they are just too big to be sent through the current 4. efficient and inexpensive method for the reception of ice information in the form of verbal consultation. add that to the variation in 1990 and you have a 1995 variation of14°50′ W Variation remains the same for any heading of the ship at a given locality.com Capt. it is not the same on all headings. Courses and bearings by these compasses must be carefully differentiated by the abbreviations PSC (per standard compass). The magnetic steering compass is located in the pilothouse. Chief Mate’s Oral preparation sreekarduppalli@hptmail. the magnetic compass. before reaching the correct heading. where the magnetic forces producing deviation are not as strong. where it is affected considerably by deviation. PSTGC (per steering compass).A turn from the south leads.com Capt.Although deviation remains a constant for any given compass heading. 2. DEVIATION The amount a magnetic compass needle is deflected by magnetic material in the ship is called deviation. decreases. increases. and PGC (per gyrocompass). Muduli FUN 1 . and decreases again as the ship goes through an entire 360° of swing. Usually the standard compass is topside. So to roll out on the correct heading one must roll out of the turn. 79 Prepared By: SREEKAR REDDY DUPPALLI way the ship is heading. So to roll out on the correct heading one must roll out of the turn. 3. past the correct heading. The standard compass provides a means for checking the steering compass and the gyrocompass. Turning Error A turn from the north lags or indicates a turn in the opposite direction. points steadily in the general direction of the magnetic north pole. if affected only by variation. Deviation gradually inc reases. 4. Oscillation is a combination of all of the other errors.com Capt. Muduli FUN 1 . any increase in airspeed (Acceleration) will cause the magnetic compass to indicate a false turn toward the north. and any decrease in airspeed (deceleration) will cause the magnetic compass to indicate a false turn toward the south. When setting the gyroscopic heading indicator to agree with the magnetic compass. Chief Mate’s Oral preparation sreekarduppalli@hptmail. use the average indication between the swings. 80 Prepared By: SREEKAR REDDY DUPPALLI REMEMBER: THE SOUTH LEADS AND THE NORTH LAGS and THERE IS NO ACCELERATION / DECELERATION ERROR ON A NORTH OR SOUTH HEADING. 5. Oscillation Error This error is caused by turbulence or rough control movements and results in erratic movement of the compass card. and it results in the compass card swinging back and forth around the heading being flown. Acceleration and Deceleration Error When on an east or west heading. REMEMBER: ACCELERATE NORTH & DECELERATE SOUTH and THERE IS NO TURNING ERROR ON A EAST OR WEST HEADING. Dip is greatest near the poles and least near the Magnetic Equator. therefore. This error is most pronounced on an east / west heading. Since the card is balanced in fluid. When making a turn from a northerly heading. but will point increasing downward as it is moved closer to the Magnetic Pole. 81 Prepared By: SREEKAR REDDY DUPPALLI 6. The needle of your magnetic compass will be parallel with Earth’s surface at the Magnetic Equator. the card is also banked as a result of centrifugal force. The compass card is designed to operate in the horizontal. any movement from the horizontal plane introduces dip error. it gives an indication of a turn in the correct direction but at a faster rate. the aft end of the compass card is tilted upward when accelerating. Magnetic dip Error Magnetic dip is the tendency of the compass needles to point down as well as to the magnetic pole. When accelerating on an east or west heading. Chief Mate’s Oral preparation sreekarduppalli@hptmail. While the card is banked. the error indicates a turn to the north. When decelerating on an east or west heading the error is toward the south. and downward when decelerating during airspeed changes. when the aircraft turns. When making a turn from the south. Acceleration error is also due to the dip of the Earth’s magnetic field.com Capt. the vertical component of the Earth’s magnetic field causes the north- seeking ends of the compass to dip to the low side of the turn. Northerly turning error is due to the mounting of the compass. Muduli FUN 1 . the compass briefly gives an indication of a turn in the opposite direction. Because of the way the compass card is mounted. It is fairly common to be asked what you'd be concerned with as Chief Mate when it comes to Passage Planning. what does he want to hear? What would a Chief Officer be concerned with in relation to Passage Planning? Waste Management Load Line Zones Expected Navigation Weather Conditions Hours of Work and Rest Maintenance Ballast Water Management Stability Security "As Chief Officer I would need to consider a lot of things when looking at the Passage Plan.com Capt. So. Chief Mate’s Oral preparation
[email protected] already knows you know that. I would need to look at how I can keep my ship and my crew in compliance with all Regulations whilst ensuring that the crew get adequate rest. and the examiner probably doesn't want to hear the old APEM . the task of double- checking the Passage Planning Officer's work is often delegated to the Chief Mate. Muduli FUN 1 . 82 Prepared By: SREEKAR REDDY DUPPALLI Passage Planning as Chief Mate Although Passage Planning is ultimately the responsibility of the Master. when sea temperature is at its highest). or when will there be a pilot onboard? All of this needs to be considered so that I as Chief Officer can plan ahead to ensure all crewmembers are within their Hours of Work and Rest. If transiting through dangerous areas also.com Capt. the stability of the ship would need to be taken into account to make sure we are always in compliance with the intact stability criteria. as we did on my last ship. The weather conditions would of course be important – we would need to look at the forecast weather and possibly alter the passage plan while en route if the forecast changes. and that it is planned well in advance for efficiency. I’d take a look at the planned maintenance that needs to be done. As these thermals rise the temperature drops (at 9. This causes the seas temperature to rise to 27°C and above. The expected navigational requirements during the voyage would also be important – when are we going to need a Senior Officer on the Bridge. or in the Load Line Regulations themselves." Tropical storms form whenever sea temperatures rise above 27 °C and can be up to 650km across. They occur where the trade winds converge and often when the ITCZ has migrated to its most Northerly extent allowing air to converge or come together at low levels. we would need to ensure that we are navigating in Load Line Zones that we are allowed to navigate in – this would be done by checking the Load Line Zone Map in Ocean Passages for the World. to make sure that we do not put the vessel in heavy weather and that we take the most navigationally advantageous route with regards to wind and current.com). and make sure each job is done at the best possible time. The suns heat passes through our atmosphere and warms the ocean water throughout the summer. Ballast Water Management would need to be considered – depending on which method we use. which encourages evaporation and the rising of air and water vapour up through the atmosphere in thermals (find out more from USA Today. The sea is constantly moving and heat is redistributed to deeper parts of the ocean so this takes quite some time (this is why hurricanes occur in late summer . 83 Prepared By: SREEKAR REDDY DUPPALLI Of course.7°C per 1000m ascent or the Chief Mate’s Oral preparation sreekarduppalli@hptmail. particularly if carrying out D1-method Ballast Water Exchange via the Sequential method. Muduli FUN 1 . the Security of the ship needs to be considered. If doing a trans-ocean passage. Latent heat is released during condensation fuelling the storm further. 50 m) of the ocean. moist air as fuel (Emanuel 1987). the SALR. 84 Prepared By: SREEKAR REDDY DUPPALLI DALR). Chief Mate’s Oral preparation sreekarduppalli@hptmail. These droplets collide together to form bigger droplets and thus helps to form huge cumulonimbus clouds. and because of the Earths rotation or spin (known as the Coriolis force or effect (click here to see an animation)). Progressively the relative humidity rises as the air ascends (as cooler air can hold less water vapour than warmer air). Eventually these droplets will collide and coalesce with one another. moist air cools as it rises in convective clouds (thunderstorms) in the rainbands and eyewall of the hurricane The water vapor in the cloud condenses into water droplets releasing the latent heat which originally evaporated the water. latent heat is released and te air cools at a slower rate. This 80°F value is tied to the instability of the atmosphere in the tropical and subtropical latitudes. and the die out. The whole storm slowly migrates across oceans towards land. Muduli FUN 1 . The pressures and weather are more stable in the eye. become bigger and fall as rain. This latent heat provides the energy to drive the tropical cyclone circulation.com Capt. In 1948 Erik Palmen observed that tropical cyclones required ocean temperatures of at least 80°F (26. Later work (e. and the lower the pressure gets in the centre of the storm relative to the pressure surrounding the storm. as the updrafts of air are balanced by descending cooled air. This warm. As a result of condensation. the whole storm starts to spiral around a central more calm point.. though actually very little of the heat released is utilized by the storm to lower its surface pressure and increase the wind speeds. this fuels the storm further. Gray 1979) also pointed out the need for this warm water to be present through a relatively deep layer (~150 ft. The Earth's atmosphere acts to balance this out as air rushes from surrounding high pressure areas to the centre of the storm along the pressure gradient. This creates the high winds in the storm. eventually this causes the water vapour to condense into tiny droplets around dust and pollen (condensation nuclei). Because the air has risen in the centre of this storm. known as the eye. the stronger the winds will become as the pressure gradient steepens. As tropical storms pass over land they lose their source of energy. Why do tropical cyclones require 80°F (26. but below this value the atmosphere is too stable and little to no thunderstorm activity can be found ( Graham and Barnett 1987).5°C) ocean temperatures to form ? Contributed by Chris Landsea (NHC) Tropical cyclones can be thought of as engines that require warm. an area of low atmospheric pressure exists at the surface.5°C) for their formation and growth.g. Above this temperature deep convection can occur. Muduli FUN 1 .com Capt. 85 Prepared By: SREEKAR REDDY DUPPALLI Ocean currents and gyres East Greenland North Icelandic Arctic Ocean Norwegian Transpolar Drift Stream Angola Antilles Azores Currents Baffin Island Benguela Brazil Atlantic Ocean Canary Cape Horn Caribbean East Greenland East Iceland Falkland Chief Mate’s Oral preparation sreekarduppalli@hptmail. 86 Prepared By: SREEKAR REDDY DUPPALLI Florida Guinea Gulf Stream Irminger Labrador Lomonosov Loop North Atlantic North Brazil North Equatorial Norwegian Portugal Slope Jet South Atlantic South Equatorial West Greenland West Spitsbergen Agulhas Agulhas Return East Madagascar Indian Ocean Equatorial Counter Indian Monsoon Indonesian Throughflow Chief Mate’s Oral preparation
[email protected] Capt. Muduli FUN 1 . 87 Prepared By: SREEKAR REDDY DUPPALLI Leeuwin Madagascar Mozambique Somali South Australian South Equatorial West Australian Alaska Aleutian California Cromwell Davidson East Australian East Korea Warm Equatorial Counter Pacific Ocean Humboldt Indonesian Throughflow Kamchatka Kuroshio Mindanao North Equatorial North Korea Cold North Pacific Chief Mate’s Oral preparation sreekarduppalli@hptmail. Muduli FUN 1 .com Capt. and in bays and estuaries along the coast. near the shore. 88 Prepared By: SREEKAR REDDY DUPPALLI Oyashio South Equatorial Tasman Front Antarctic Circumpolar Southern Ocean Tasman Outflow Indian Ocean Gyre North Atlantic Gyre Major gyres South Atlantic Gyre North Pacific Gyre Gyres South Pacific Gyre Beaufort Gyre Other gyres Ross Gyre Weddell Gyre What's the difference between a tide and a current? Tides go up and down. Pictured: Lowtide in Islesboro. Tides are driven by the gravitational force of the moon and sun. Tides are characterized by water moving up and down over a long period of time. Muduli FUN 1 . Tides create a current in the oceans. currents move left and right. Maine.com Capt. Chief Mate’s Oral preparation sreekarduppalli@hptmail. the speed is very less. Currents The sun's heat on the equator heats the oceans whereas at the north and south polar regions the ocean water is not heated as much. near the shore. Muduli FUN 1 . Chief Mate’s Oral preparation sreekarduppalli@hptmail. One is the rise and fall of the tides. as compared to ocean currents. Tidal stream is the last & the first movements of water of the ebb & rising tide. A second factor that drives ocean currents is wind. and in bays and estuaries along the coast. Cold water is denser than warm so the cold water tends to flow along the bottom of the ocean. A third factor that drives currents is thermohaline circulation . Drifts are any buoyed up body moved by surface water movements &/or movement caused by winds.15 miles per hour).a process driven by density differences in water due to temperature (thermo) and salinity (haline) in different parts of the ocean. Tides create a current in the oceans. created by colder water sinking to greater depths. Oceanic currents are driven by several factors.85 kilometers per hour or 1. Waves are caused by the action of wind on the surface of the ocean and the winds are in turn caused by the heat of the Sun. These are called "tidal currents. Currents driven by thermohaline circulation occur at both deep and shallow ocean levels and move much slower than tidal or surface currents.com Capt." Tidal currents are the only type of currents that change in a very regular pattern and can be predicted for future dates. 89 Prepared By: SREEKAR REDDY DUPPALLI When used in association with water. where huge bodies of water move from one continent to another. tidal stream and drifts? Ocean currents are the result of the movement of water due to rotation of the Earth on it axis. So between equitorial region to polar region. Here at least in the first hour. warmer water flows on the surface & from polar to equitorial region. What is the difference between ocean current. These currents are generally measured in meters per second or in knots (1 knot = 1. It also occurs when warmer water from the equatorial region goes to the polar region. Winds drive currents near coastal areas on a localized scale and in the open ocean on a global scale. the term "current" describes the motion of the water.below the depths. Winds drive currents that are at or near the ocean's surface. as to fill in the vacuum. he has to quickly decide the course of action keeping in mind the after effects of the same. Muduli FUN 1 . Tides Tides are caused by the gravity of both the Moon and the Sun How to do Intentional Grounding or Beaching of a Ship? The master of the ship is the overall in charge of the operations while trading in international waters.com Capt. rudder etc. This sets up the complex pattern of currents. Why Beaching is done? The three main reasons for which Beaching of ship is done are: To prevent loss of ship due to flooding when there is major damage below the water line of the ship To refloat the ship when satisfactory repair has been done and water tight integrity is restored In order to hand it over to the scrap yard Procedure to Perform Beaching of Ship: Ballast the ship to its maximum capacity Check where the damage is more-bow side or stern side. Head with the damage side for beaching with 90 o to the tides Take all measure to avoid ship going parallel to the beach (throw weather anchor first) Chief Mate’s Oral preparation sreekarduppalli@hptmail. One kind of emergency situation which can really test skills and ability of a ship’s captain is - Beaching of the ship. 90 Prepared By: SREEKAR REDDY DUPPALLI In order to maintain a level warm water flows in the opposite direction at the surface. The word Beaching is used for such process because the type of emergency grounding is done only in those areas where the ground is of soft mud or sand (as in a Beach) in order to avoid damage to ship’s hull. propeller. When it comes to safety of the crew and ship. What is Beaching of the ship? Beaching is a process wherein during an emergency situation a ship is intentionally taken towards shallow waters and at last grounded. to run his ship aground. in case of emergency.com Capt. ship and/or cargo easier and less costly) Take at least following actions: Engines stopped Sound general alarm Watertight doors to be closed VHF watch maintained on channel 16 Broadcast to other vessels Chief Mate’s Oral preparation
[email protected]. the master may decide. in order : to save what can be saved to avoid a dramatic collision to avoid to be caught on the lee shore in very bad weather (e. drop both the anchor at good distance so that they can assist the vessel in heaving when going water Sounding of all tanks must be done before and after beaching Beaching (by own will) Sometimes. 91 Prepared By: SREEKAR REDDY DUPPALLI If approaching from astern due to stern damage. engine breakdown or when the engines are not powerful enough to ride the storm) to avoid the ship from stranding where salvaging would be too difficult or even impossible (rocks. by his own will or in agreement with the Insurance Company and/or the P & I Club. heavy current) to avoid the ship from sinking in deep water (which would make the salvage of the crew. breakers. Muduli FUN 1 . EPIRB's. abandon ship) o secure position (change of tide. >CHECK THE DEPTH OF WATER AROUND THE SHIP AND CONFIRM THE NATURE OF BOTTOM. > SOUND ALL BILGES AND TANKS. >SLACK WATER AFTER THE HIGH TIDE IS THE BEST TIME TO BEACH THE VESSEL. >DO NOT STOP ENGINES IMMEDIATELY ON TOUCHING BOTTOM. INSPECT THE SHIP FOR DAMAGE. >TAKING BALLAST IN THE END AGROUND AFTER BEACHING WILL HELP TO KEEP IT THERE FIRMLY. >KEEP ENOUGH STEERAGEWAY TO PREVENT DRIFT OF SEAWARD END.REDUCE POSSIBILITY OF POUNDING. THIS WILL MAKE THE REFLOATING MUCH EASIER. satellite terminal and other automatic distress transmitter (GMDSS) Consider danger of the situation and if possible take pictures Consider further actions with consideration for: o salvage o risks of sinking (emergency message. Muduli FUN 1 . oil spills Keep the Company always informed Enter every action taken in the log book BEACHING PROCEDURE AND PRECAUTIONS:- >IF TIME AND PREVAILING CIRCUMSTANCES ALLOW. stability) o assistance. port of refuge. TAKE FULL BALLAST. use anchors Sound bilges. > LAY OUT THE ANCHORS AND CABLES AT THE PROPER POSITIONS. stress risks. stream. Light / Shapes to be exhibited Deck lighting switched on If necessary. tanks and overside around vessel (see also Stranding Evaluate risks of pollution Inform company and any third parties if relevant Update if necessary vessel's position in radio room. DRIVE UP THE SHIP FIRMLY ASHORE. >APPROACH THE BEACH AT RIGHT ANGLES.com Capt. ALLOWANCE SHALL BE MADE FOR WIND AND TIDE. weather. 92 Prepared By: SREEKAR REDDY DUPPALLI Sound signals. HATCHES MAY HAVE SPRUNG FROM THEIR SEATING AND CAUSE FLOODING LATER. Chief Mate’s Oral preparation sreekarduppalli@hptmail. COMPARING WITH FLOATATION DRAFT GIVES A ROUGH IDEA OF THE LOST BUOYANCY USING THE TPC FIGURES. at a recoverable location. direction. obstructions/obstacles present) check details of tide (tidal heights. If unable to beach around this time period. in the event of an uncontrolled fire. consider the type of bottom. or simply to carry out underwater repairs. Muduli FUN 1 . Beaching A vessel may be beached for many reasons. or cleaning of a foul bottom. tide times) beach the vessel at 90o to the beach line (level ground) beach approximately 1-2 hours after high water (to ensure sufficient water to refloat). how level is it. 93 Prepared By: SREEKAR REDDY DUPPALLI >NOTE THE DRAFT. Ballast the vessel to its maximum draft by whatever reversible means needed to refloat it stop engines prior to making contact (cooling water intake protection) Chief Mate’s Oral preparation sreekarduppalli@hptmail. inspections. Points to consider (during beaching): select the beaching site carefully (if the time permits. maybe to save it from foundering in deep water or to flood her.com Capt. lay out anchors (fore and aft depending on weather conditions) if vessel is moving on bottom. 94 Prepared By: SREEKAR REDDY DUPPALLI once vessel has grounded. add extra weights.com Capt. Muduli FUN 1 . remove ballast if it was added . if deep keel vessel. consider shoring up (prevent vessel lying into the sea for refloating purposes). Refloating: § attempt to refloat as soon as vessel reaches flotation draft. Modified Lateral Buoys and Marks for 'A Region' Chief Mate’s Oral preparation
[email protected] an even trim § bleed cooling systems § use anchors to kedge the vessel. is divided into two sections. The current edition of Notices to Mariners. 95 Prepared By: SREEKAR REDDY DUPPALLI Modified Lateral Buoys and Marks for 'B Region' Annual Summary of Notices to Mariners : What is NP247(1)? The annual summary of admiralty notices to mariners. superseding and cancelling the previous one. and changes in shipping channels. Muduli FUN 1 . aids to navigation. also popularly known by its publication number NP 247 (1) and (2).com Capt. This annual summary is of prime importance to mariners in keeping navigational chart folio up to date for corrections pertaining to temporary and Chief Mate’s Oral preparation sreekarduppalli@hptmail. hydro graphic information. The notices advice mariners on important matters related to ship’s navigation. is a publication issued by admiralty (UKHO) on yearly basis. NP 247(2) What are the contents of NP 247(1)? In this publication the contents are in two sections namely – Section 1 – Annual Notices to Mariners Section 2 – Temporary and Preliminary Notices Starting with an index which consists of a note displaying that the current annual summary replaces the previous one. It contains port state notifications issued under the EU Directives and some parts of ship navigation related regulations issued by the United States. an edition of 2013 of Annual summary would deal with notices applicable till the end of year 2012 comprehensively. firing practice areas. the first section deals with annual notices for the current year for e. protection of historic. 96 Prepared By: SREEKAR REDDY DUPPALLI preliminary notices for ship’s navigation and sailing directions. The index is preceded by further detailed description of each notice mentioned in it. The Annual Summary of Admiralty notices to mariners is divided into two parts: 1.com Capt. The annex provided with the notice contains extracts from the US navigation safety rules. This information is significant for mariners to keep a track of any previous notice that has Chief Mate’s Oral preparation sreekarduppalli@hptmail. mine laying operations. dangerous and military wreck sites etc. NP 247(1) 2. along with vital information about tide tables. safety of British ships in event of war crisis. thus enabling mariners to check any chart or any T & P correction applicable to the chart right from its edition date. The annual summary serves as a database with details of history of corrections for all the charts and sailing directions published by the British Admiralty or UKHO. Muduli FUN 1 . The publication also includes an exhaustive list of traffic separation schemes and information related to ship routeing system shown on admiralty charts.g. which should be cancelled and destroyed. The second important section of the navigation publication contains a numerical index of temporary and preliminary notices which are in force since the end of the previous year. suppliers of admiralty charts and publications. voluntary reporting schemes. A detailed index of notices is provided regarding navigational importance with respect to the British Isles. Muduli FUN 1 .Temporary and preliminary Notices to Mariners still in force at the start of the year. Published at the beginning of the year in two parts . It contain the text of all updates to current editions of admiralty sailing direction as well as miscellaneous publications. is a publication issued by Admiralty (UKHO)on yearly basis.com Capt. What is Annual Summary Of Admiralty Notices To Mariners? The annual summary of admiralty notices to mariners. navigational charts are found marked with Temporary and Preliminary notices which are no more in force or have been cancelled or some notices are found missing. hydrographic information. and changes in shipping channels. Mariners can thus always refer to the Annual Summary and keep their navigational chart folios up to date. The notices advice mariners on important matters related to ship’s navigation. the ship’s navigating officer can always refer to Annual Summary of Notice to appraise the status of corrections before planning passage in order to keep navigational charts up to date. aids to navigation. Thus while preparing for such inspections. and a Cumulative Summary of Amendments to Admiralty Sailing Directions.Namely 247(1) AND 247(2) 247(1) Annual notices to mariners . cancelled or not in force any further. 247(2) Cummulative summary of amendments to current editions of all volumes of sailing direction and miscellaneous publication. Important Notes: Often during Oil Major Inspections observations. also popularly known by its publication number NP 247 (1) and (2). a summary of Temporary and Preliminary Notices to Mariners still in force at the start of the year. 97 Prepared By: SREEKAR REDDY DUPPALLI been missed out. Annual Summary of Admiralty Notices to Mariners (NP247) contains the Annual Statutory Notices to Mariners Numbers 1-26. It contains reprints of T/P notices Corrections to sailing directions Corrections for tide tables Contents:- SECTION 1 ANNUAL NOTICES TO MARINERS 1–26 Chief Mate’s Oral preparation sreekarduppalli@hptmail. 98 Prepared By: SREEKAR REDDY DUPPALLI SECTION 2 TEMPORARY AND PRELIMINARY NOTICES What is Admiralty List Of Notices To Mariners? Admiralty NMs contain all the corrections. # List Of Enforced Navareas Quarterly. NOTE:- 1. The Admiralty Notices to Mariners service provides all of the data you need to maintain our products. 3. Contains information. Fog signals . They should be retained until the next annual summary to admiralty notices to mariners is received. However weekly editions dating as far back as 18 months may be required and must be kept safely on board. 4. 2. # List Of Publications In Current Usage Quarterly. Contents Of WNTMs : # T/P Notices On The Last Week Of The Month.079 Views Navigationally significant changes to Nautical Charts . which are despatched directl y from the UKHO. What is Weekly Notices To Mariners (WNTM) and its sections? 1. alterations and amendments for the UKHO’s worldwide series of Admiralty Charts and Publications. Radio signals and sailing directions are published in weekly notice to mariners. Lights . Admiralty Charts and Publications should be maintained so that they are fully up-to-date for the latest safety-critical navigational information. Chief Mate’s Oral preparation sreekarduppalli@hptmail. The hydrographer of the navy publishes them. Reprints of all Radio navigational warnings in force and a summary of charts & publication being published.com Capt. which enables the mariner to keep his charts and books published by the hydrographic department up to date for the latest reports received. Muduli FUN 1 . They are published weekly in several formats but best known as the weekly booklets. Asterix alongside these items of correction indicate original information i. cancel as per cancellation or enforced list. HYDROPACS: Atlantic And Mediterranean Sea. Muduli FUN 1 . Geographical Index.com Capt. Blocks And Notes Accompanying Notices In This Section Are Placed Towards The End Of This Sections.Temporary And Preliminary Notices. Items tagged ‘PL’ are new editions of charts. 1. SECTION 3: Reprints Of Radio Navigational Warnings 21 NAV areas to be filed. 99 Prepared By: SREEKAR REDDY DUPPALLI List Of Sections Of Weekly Notices To Mariners. Astersk mark (*) in all column of light indicates new light SECTION 6: Ammendments To Admiralty List Of Radio Signals Chief Mate’s Oral preparation sreekarduppalli@hptmail. suppliers information. SECTION 1: Explanatory Notes. Last correction date is given below the actual correction. 4. 3. Section 4: Ammendments To Sailing Directions Updates to all sailing directions are given under section 4. NP 274 (2) SECTION 5: Ammendments To Admiralty List Of Lights And Fog Signals.e information gathered by the british hydrographer and not by other country’s authorities SECTION 2: Updates To Standard Navigatinal Charts & Admiralty NTMS. They are issued by the united states coast guard: HYDROLANTS: Warnings For Pacific And Indian Oceans. those enforced at the end of year are reprinted in The Annual Summary Of Admiralty Notices to mariners part 2 . Chart Number / Notice Number. Use Of Charts And Associated Publications. Updates of all list of lights are given in section 5 and may be published in an earlier editions than the chart updating notices. chart corrections. Notice Number / Page / Chart / Folio Number. 2. Hydrolants and Hydropacs to be filed along with nav warnings file itself. Astersk mark (*) indicates change in light. Muduli FUN 1 . 9. 3. 10. SECTION 7: Miscellaneous Publication Updates Miscellaneous Publication Includes: 1. Information relevant to admiralty digital products and services. 6. 8. 4. Admiralty guide to ENC symbol used in ECDIS.com Capt. 5. Paper chart maintenance record (NP133A) SECTION 8 : Admiralty Digital Products And Services. 100 Prepared By: SREEKAR REDDY DUPPALLI Updates to all the radio signals are given in section 6 . New Zealand and Japanese charts (indicated by the prefixes AUS. Updates should be cut out and pasted into the appropriate volumes.e ( issued date is clearly mentioned on the first page). Nautical almanac publication. that publication may have been in the form of a new chart or a new Chief Mate’s Oral preparation sreekarduppalli@hptmail. Admiralty tide table. The edition date quoted indicates the month and year of publication of the current edition of navigational charts. Symbols and abbreviations used on admiralty paper/charts.. including adopted Australian. What is Cumulative List of Admiralty Notices to Mariners (NP234) ? The Cumulative List of Admiralty Notices to Mariners(NP 234 A/B) records the date of issue of the current edition of each navigational chart and of subsequent relevant Notices to Mariners issued since last published cumulative list of admiralty notices to mariners i. 7. How to keep your admiralty products updates. NZ and JP respectively). 2. Ocean passage for the world. Chart numbers refer to navigational charts in the Admiralty series. Mariner handbook. IALA maritime buoyage system. Admiralty distance table. However. the officer in charge has to take independent decisions to ensure a smooth passage of the ship. A list of all nautical charts available and a complete list of all notice to mariners affecting them during the previous two years. wherein the officer on watch must call the ship’s master to the bridge to avoid any kind of danger for the ship. he is the representative of the ship’s master and must carry out all the orders as put forth by the latter. A chart carrying an earlier edition date than that quoted in this list is no longer valid and should be replaced. 101 Prepared By: SREEKAR REDDY DUPPALLI edition (the relevant date is given in the bottom outside margin of the chart). 2. every shipping company provides a list of situations. and it is imperative for every OOW to follow them. While navigating the ship. wherein the officer on watch should call the ship’s master Danger to the ship because of traffic or movement of other ships Danger to ship or ship’s stability because of heavy weather Malfunctioning of alarms or signalling equipment On encountering restricted visibility Chief Mate’s Oral preparation sreekarduppalli@hptmail. The list is published annually. While on the bridge. The Cumulative List of Admirality Notices to Mariners (NP234 A/B) assists users who wish to identify outstanding NMs and audit trails for a particular chart or charts. The Cumulative List of Admiralty Notices to Mariners is available without subscription from Admiralty Distributors. Published in January and June/ July of each year . Below is the checklist of situations. Cumulative List of Admiralty Notices to Mariners records the date of issue of the current edition of each navigational chart and of subsequent relevant Notices to Mariners issued since 1. with Part A in January and Part B in July. When Should Officer on Watch (OOW) Call the Ship’s Master? The Officer on Watch (OOW) when on duty is in charge of the ship’s navigation and safety. These instructions are given in the shipboard operational procedures. Muduli FUN 1 .com Capt. the officer in charge should always call the master in case of an emergency or when in doubt about a particular situation. icebergs. The continuous synopsis record provides an onboard record of the history of the ship with respect to the information recorded therein. Following details should be present in the continuous synopsis record (CSR) Chief Mate’s Oral preparation sreekarduppalli@hptmail. 102 Prepared By: SREEKAR REDDY DUPPALLI Difficulty in maintaining a proper course Breakdown of propulsion system. steering gear. According to SOLAS chapter i. all passenger and cargo ships of 500 gross-tonnage and above must have a continuous synopsis record on board. the master would take the control of the ship.com Capt. which would fly its flag. Once on the ship. Continuous synopsis record (CSR) is issued by the administration of the ship. This has to be recorded in the ship’s logbook. or shipwrecks Failure to sight land or navigation mark Sudden change in sounding or readings at inappropriate time On encountering suspicious ship or boat heading towards the ship On receiving emergency or important message from nearby port or ship On encountering any suspicious floating object in piracy affected area Apart from the above mentioned situations. Muduli FUN 1 . What is Continuous Synopsis Record (CSR) of Ships? Continuous synopsis record is a special measure under Safety of life at sea (SOLAS) for enhancing the maritime security at the sea. or machinery Malfunctioning of radio equipment During manoeuvring On sighting land or navigation mark that can turn out to be dangerous Breakdown of essential navigational equipment On encountering navigational hazards such as rocks. a translation in the language of the administration may be provided. to the ship and the name of the body which has carried out the verification on the basis of which the certificate was issued The date of expiry of the ship’s registration with the state Any changes made related to the above mentioned points should be mentioned in the continuous synopsis record. to the company operating the ship. Officially.com Capt. Muduli FUN 1 . The Continuous Synopsis Record (CSR) is mentioned in SOLAS –Chapter XI-1. its registered address and the address from where safety management activities are carried out Name of the administration or the contracting government or the recognized organization which has issued the document of compliance. Chief Mate’s Oral preparation sreekarduppalli@hptmail. or French language. specified in the ISPS code. The continuous synopsis record shall always be kept on board ship and shall be available for inspection all the time. however. specified in the ISM code. the record should be in English. Spanish. Name of the body which has carried out the audit to issue the document of compliance Name of the administration or the contracting government or the recognized organization which has issued the safety management certificate (SMC) to the ship and the name of the body which has issued the document Name of the administration or the contracting government or the recognized organization which has issued the international ship security certificate. 103 Prepared By: SREEKAR REDDY DUPPALLI Name of the ship The port at which the ship is registered Ship’s identification number Date on which ship was registered with the state Name of the state whose flag the ship is flying Name of registered owner and the registered address Name of registered bareboat charterers and their registered addresses Name of the classification society with which the ship is classed Name of the company. examinations and inspections indicated in this register are based on the requirements of ILO Convention. Name of Ship 2.com Capt. in an approved format which is to be maintained upto date as per requirement of the dock safety regulation and endorsed & signed by a competent person as required. Muduli FUN 1 . It contains certificate of tests and registers all reports of examination of load bearing machinery. Date of Issue 8. winches and hoists. Chain/Wire = 5 Rope = 6 Chief Mate’s Oral preparation sreekarduppalli@hptmail. chains and wire ropes before they are put in use. Signature and Stamp Part I: Entries concerning four yearly examinations and annual examinations. Register Number 7. Part II: Contains entries concerning thorough annual examinations of cranes. Name of Owner 6. Port of Registry 5. Part IV: For entries concerning the annealing of gear. Issued by 9. e. Part III: For entries concerning the thorough annual examination of gear exempted from annealing. Accessory gear other than derricks is also included. The tests. and to establish periodically that they continue to be in safe working order to the satisfaction of a Cover: 1. 104 Prepared By: SREEKAR REDDY DUPPALLI What is Chain Register and its contents ? It is a booklet called form 99. Call Sign 4. They are intended to ensure that ships having lifting appliances are initially certified by a competent person. Official Number 3.g. The last page contains some recommended factors of safety. The term “thorough examination” means a detailed visual examination by a competent person. raising or lowering loads or moving them from one position to another while suspended or supported. The register is designed by the dockyard for 8 years and must be retained on board for a period of four more years after the new one comes into force. The term “responsible person” means a person appointed by the master of the ship or the owner of the gear to be responsible for the performance of inspections and has sufficient knowledge and experience to undertake such inspections. Muduli FUN 1 . 105 Prepared By: SREEKAR REDDY DUPPALLI Derrick = 9 Test certificates are attached to the register by means of gummed strips provided on the inside of the cover. The term “competent authority” means a minister.com Capt. orders or other instructions having the force of law. the loose gear or sling is safe for continued use. government department or other authority empowered to issue regulations. so far as can be ascertained in such manner. Definitions The term “competent person” means a person possessing the knowledge and experience required for the performance of thorough examinations and tests of lifting appliances and loose gear and who is acceptable to the competent authority. The term “lifting appliance” covers all stationary or mobile cargo-handling appliances used on board ship for suspending. Chief Mate’s Oral preparation sreekarduppalli@hptmail. The term “inspection” means a visual inspection carried out by a responsible person to decided whether. supplemented if necessary by other suitable means or measures in order to arrive at a reliable conclusion as to the safety of the lifting appliance or item of loose gear examined.