Seamanship Techniques 2011 E Part 6 ppt

183Boatwork admit sufficient daylight to the inside of the lifeboat with the hatches closed to make artificial light unnecessary. 8. Its exterior is of a highly visible colour and its interior of a colour which does not cause discomfort to the occupants. 9. Handrails provide a secure handhold for persons moving about the exterior of the lifeboat and aid embarkation and disembarkation. 10. Persons have access to their seats from an entrance without having to climb over thwarts or other obstructions. 11. The occupants are protected from the effects of dangerous subatmospheric pressures which might be created by the lifeboat’s engine. Capsize and Re-righting The boats shall all be fitted out with safety seatbelts designed to hold a mass of 100 kg when the boat is in the capsized position. To this end it is essential that the occupants once embarked are securely strapped into the seated areas to ensure the self righting property of the boat becomes a viable proposition. Also all hatches and access doors are battened down and are seen to be in a watertight condition. The design of the boats should be such that in the capsized situation the boat will attain a position which provides an above water escape. Exhausts and engine ducts will be so designed as to prevent water entering the engine during a capsized period. Embarkation and Launching of Survival Craft This information is taken from the 1983 Amendments to the International Convention for the Safety of Life at Sea, 1974. Launching when Parent Vessel is Making Way Cargo ships of 20,000 tons gross tonnage and upwards, should have lifeboats capable of being launched, where necessary utilising painters, with the ship making headway at speeds up to 5 knots in calm water. Free Fall Lifeboats Lifeboats arranged for free fall launching shall be so constructed that they are capable of rendering protection against harmful accelerations resulting from being launched when loaded with its full complement of persons and equipment from at least the maximum height at which it is designed to be stowed above the water line. Allowing for the ship to be in its lightest sea-going condition, under unfavourable conditions of trim of up to 20° and with a ship’s list of up to 75° either way. Release Mechanism Every lifeboat to be lauched by a fall or falls shall be fitted with a release mechanism which complies with the following: 184 Seamanship Techniques (a) the mechanism shall be so arranged that all hooks release simultaneously; (b) the mechanism shall have two release capabilities, namely, (i) A normal release capability which will release the craft when waterborne or when there is no load on the hook. (ii) An on-load release capability which will allow the release of the craft when load is on the hooks. This will be so arranged as to release the boat under any condition from no load with the boat in the water, to when a load of 1.1 times the total mass of the lifeboat (fully loaded) is acting on the hooks. The release mechanism should be adequately protected against accidental or premature use. (c) The release control should be clearly marked in a contrasting colour. (d) The mechanism shall be designed with a safety factor of 6 based on the ultimate strength of materials used, assuming the mass of the boat is equally distributed between falls. Painter Release Every lifeboat shall be fitted with a release device to enable the forward painter to be released when under tension. Lifeboats with Self-Contained Air Support Systems Lifeboats with self-contained air support systems shall be so arranged that when the boat is proceeding with all entrances and openings closed, the air inside the lifeboat remains pure and the engine runs normally for a period of not less than 10 minutes. During this period the atmospheric pressure inside the boat shall never fall below the outside atmospheric pressure, nor shall it exceed it by more than 20 mbar. The system shall be provided with visual indicators to indicate the pressure of the air supply at all times. Fire Protected Lifeboats A fire protected lifeboat, when waterborne, shall be capable of protecting the number of persons it is permitted to accommodate when subjected to a continuous oil fire that envelops the boat for a period of not less than 8 minutes. Water Spray Systems A lifeboat with a water spray system shall comply with the following: 1. Water for the system shall be drawn from the sea by a self priming motor pump. It shall turn ‘on’ and turn ‘off ’ the flow of water over the exterior of the lifeboat. 2. The seawater intake shall be so arranged as to prevent the intake of flammable liquids from the sea surface. 3. The system shall be arranged for flushing with fresh water and allowing complete drainage. 185Boatwork 35 hp motor Sheaves on rust resistant shafts Limit switch Lowering away Boarding position Bronze sheaves on rust resistant shafts Lowering control wire Securing wire sliphook Figure 7.13 Watercraft-Schat launching system. 30. Totally enclosed boat in davit arrangement. 186 Seamanship Techniques PARTIALLY ENCLOSED BOATS (AS DEFINED BY REGULATION 42) 1. Partially enclosed boats must comply with the general requirements for lifeboats. 2. Every partially enclosed boat shall be provided with effective means of bailing or be automatically self bailing. 3. They shall be provided with permanently attached, rigid covers extending over not less than 20 per cent of the boat’s length from the stem, and 20 per cent of the length from the most after part of the boat. The lifeboat will be fitted with a permanent attached foldable canopy which together with the rigid covers completely encloses the occupants of the boat in a weatherproof shelter and protects from exposure. Arrangement of the Canopy (a) The canopy must be provided with adequate rigid sections or battens to permit the erection of the canopy. (b) It must be easy to erect by not more than two persons. (c) It must be insulated to protect the occupants against heat and cold, having not less than two layers of material separated by an air gap or other efficient means of insulation. Means must be provided to prevent the accumulation of water in the air gap. (d ) Its exterior should be of a highly visible colour and the interior colour should not cause discomfort to the occupants. (e) It has entrances at both ends and on each side provided with efficient adjustable closing arrangements which can be easily and quickly opened and closed from inside or outside so as to permit ventilation but exclude the seawater, wind and cold. Means shall also be provided for holding the entrances securely in the open and closed positions. ( f ) With the entrances closed it admits sufficient air for the occupants at all times. ( g) It has means for collecting rainwater. (h) The occupants can escape in the event of the lifeboat capsizing. 4. The interior of the lifeboat should be of a highly visible colour. 5. The radio installation required by the regulations shall be installed in a cabin large enough to accommodate both the equipment and the operator. No separate cabin is required if the construction of the lifeboat provides a sheltered space to the satisfaction of the certifying authority. Marine students should note that the above is for partially enclosed lifeboats, and not self-righting, partially enclosed boats, which is covered by Regulation 43. Lifeboat Additional Fittings (In accordance with the 1983 amendments of the SOLAS 1974 convention) 1. Every lifeboat shall be provided with at least one drain valve fitted 187Boatwork near the lowest point in the hull, which shall be automatically open to drain water from the hull when the lifeboat is not waterborne and shall automatically close to prevent entry of water when the lifeboat is waterborne. Each drain valve shall be provided with a cap or plug to close the valve, which shall be attached to the lifeboat by a lanyard, or chain, or other suitable means. Drain valves shall be readily accessible from inside the lifeboat and their position shall be clearly indicated. 2. All lifeboats shall be provided with a rudder and tiller. When a wheel or other remote steering mechanism is also provided the tiller shall be capable of controlling the rudder in case of failure of the steering mechanism. The rudder shall be permanently attached to the lifeboat. The tiller shall be permanently installed on or linked to the rudder stock; however, if the lifeboat has a remote steering mechanism, the tiller may be removable and securely stowed near the rudder stock. The rudder and the tiller shall be so arranged as not to be damaged by operation of the release mechanism or the propeller. 3. Except in the vicinity of the rudder and propeller, a buoyant lifeline shall be becketed around the outside of the lifeboat (see ropework in lifeboats). 4. Lifeboats which are not self-righting when capsized shall have suitable hand holds on the underside of the hull to enable persons to cling to the lifeboat. The handholds shall be fastened to the lifeboat in such a way that when subjected to impact sufficient to cause them to break away from the lifeboat, they break away without damage to the lifeboat. 5. All lifeboats shall be fitted with sufficient watertight lockers or compartments to provide for the storage of the small items of equipment, water and provisions required by the regulations. Means shall also be provided for the storage of collected rainwater. 6. Every lifeboat shall comply with the GMDSS requirements and have use of VHF radio telephone apparatus. Lifeboat/rescue boats of passenger ships would have a fixed radio installation. Other craft would employ portable two-way ‘walkie talkie’s’. 7. All lifeboats intended for launching down the side of a ship shall have skates and fenders as necessary to facilitate launching and prevent damage to the lifeboat. 8. A manually controlled lamp visible on a dark night with a clear atmosphere at a distance of at least 2 miles for a period of not less than 12 hours shall be fitted to the top of the cover or enclosure. If the light is a flashing light, it shall initially flash at a rate of not less than 50 flashes per minute over the first 2 hour period of operation of the required 12 hour operation period. 9. A lamp or source of light shall be fitted inside the lifeboat to provide illumination for not less than 12 hours to enable reading of the survival and equipment instructions; however, oil lamps shall not be permitted for this purpose. 188 Seamanship Techniques 10. Unless expressly provided otherwise, every lifeboat shall be provided with effective means of bailing or be automatically self-bailing. 11. Adequate viewing, forward, aft and to both sides of the lifeboat must be provided from the control position to allow safe launching and manoeuvring. 12. Each seating position in the boat should be clearly indicated. BOAT RIGGING Mast and Sails These are carried in boats which are generally not equipped with an engine or other means of mechanical propulsion. The mast is usually wood with metal fitments, including hounds band, traveller, and cleats. Galvanised wire shrouds and forestay (if fitted) are shackled at the masthead, being secured with rope tails or small bottle screws at the gunwale. The heel of the mast is shaped to fit the tabernacle or mast step (see Figure 7.14). The halyards are made of hemp rove through blocks at the masthead. An alternative arrangement for the main halyard is a single sheave built into the mast itself, one end of the main halyard being spliced on to the traveller. When the mast is down and stowed, the halyards and shrouds etc. are normally twisted about the length of the mast to avoid fouling when the mast is to be stepped. The heel of the mast is stowed facing forward, ready for immediate use and stepping, by walking the mast up from aft to be clamped against the mast thwart. Many alternative rigs are in use, especially in the private yacht sector of the marine world. Thole pins are often employed in place of cleats for turning up halyards. Stainless steel shackles and bottle screws have replaced rope lashings. Many ‘quick link’ securing devices have become increasingly popular for attaching sails etc. Ropework in Lifeboats Painters Standard equipment must include two painters, both stowed in the forward part of the boat. One of these shall be permanently secured to the boat and coiled down on top of the bottom boards or in the bow sheets. The second painter should be secured to the release device at or near the bow, ready for immediate use. Both painters should be of a length equal to not less than twice the distance from the stowage position of the lifeboat to the waterline when the vessel is at her lightest sea-going condition or 15 m, whichever is the greater. The size of painters is normally 20–24 mm manilla or equivalent synthetic cordage. (Man-made fibres may be used for life saving appliances provided it has been approved by the appropriate authority.) Observation of an approved man-made rope will show a coloured thread/yarn passing through the lay of the rope. The idea is based on the ‘Rogues’ Yarn’ Forestay Traveller Mast thwart Keelson Mast step (tabernacle) Heel of mast Mast clamp and securing pin Yard Yard strop Main halyard Port shroud Hounds band Starboard shroud Figure 7.14 Mast and rigging. NB. Following revision of regulations lifeboats must now be fitted with a motor. Mast and sails are therefore no longer carried as standard equipment. Mast and sail detail has been retained within the text to provide general seamanship information. 189Boatwork method of identifying the various dockyards from which ropes originally came, and so prevent theft between ships. Buoyant (becketed) Lifeline Each lifeboat will be provided with a buoyant lifeline becketed around the outside of the boat, except in the vicinity of the rudder and the propeller. These are often manufactured in a synthetic material having a wood hand grip rove in the bight. If natural cordage is used it is normally of 16 mm size, beckets being spaced approximately 60 cm apart. Its purpose is to provide hand holds for survivors in the water. With this idea in mind the height of beckets should be just clear of the water surface when the boat is fully loaded. Keel Grab Lines (if fitted) These are fitted to assist the righting of a capsized, conventional boat. They are secured inside the boat, on either side, passing from gunwale to gunwale under the keel. They will normally be secured having ‘figure 8’ knots on either side of the boat to provide hand holds, together with a sheepshank directly under the keel. This sheep shank can be released when the boat is in a capsized condition and the increased bight of the line can be used in conjunction with an oar to form a spanish windlass and so lever the boat over into a correct upright position. Keel grab lines are usually of 20 mm manilla or suitably approved cordage. Lifelines Not less than two lifelines are required for partially enclosed boats. These must be secured to the span between the davit heads and should be of sufficient length to reach the water with the ship in its lightest conditon under unfavourable conditions of trim with the ship listed not more than 20° either way. They should be of an approved cordage 20 mm size, and seized to the span not less than 30.5 cm away from the davit heads so as not to foul the fall wires. Lifeboat Falls Falls shall be constructed in corrosion resistant steel wire rope having rotation-resistant properties. An example in use is ‘Kilindo’ 18 × 7. It is a multi-strand wire which involves laying up round strands in the opposite direction to the previous layer of strands. Although termed a non-rotating rope, this is not strictly accurate because the separate layers of strands do twist, but each layer of strands turns in an opposing direction giving a balance effect when hoisting/lowering. Lifeboat falls shall be long enough for the survival craft to reach the water with the ship in its lightest seagoing condition, under unfavourable conditions of trim and with the ship listed not less than 20° either way. 190 Seamanship Techniques Maintenance Falls used in launching shall be turned ‘end for end’ at intervals of not more than 30 months and be renewed when necessary due to deterioration, or at intervals of not more than 5 years, which ever is the earlier. Rate of Descent The speed at which the survival craft or rescue boat is lowered into the water shall not be less than that obtained from the formula: S = 0.4 + (0.02 × H) where S = speed of lowering in metres per second; and H = height in metres from davit head to the waterline at the lightest seagoing condition. The maximum lowering speed is established by the authority taking note of the design of the craft, the protection of its occupants from excessive forces and the strength of the launching appliance (taking into account inertia forces during an emergency stop). Means must be included in the system to ensure that the speed is not exceeded. Bowsing in Tackles Small rope tackles, usually double luff, these are secured between the foot of the davit aboard the parent vessel and the loose linkage under the floating block. Their purpose is to relieve the weight from the tricing pendants and allow the conventional boat to be eased out away from the ship’s side during the lowering operation to the waterline (see Figure 7.15). The tackles are rove to disadvantage, with the downhaul leading into the boat. When they are secured, it is normal to use a round turn with two half hitches on the bight. This will enable the two men manning the tackles at each end to slack away together on the round turn, and also check the motion of the boat should it be going off in an uneven manner. Each block is fitted with a hook/swivel fitment to allow securing in an easy manner with minimum loss of time. Tricing Pendant This is a short length of steel wire rope, having a senhouse slip and a rope lashing at one end, with a shackle secured to the underside of the davit arm at the other end (Figure 7.15). The purpose of the tricing pendants is to ‘trice the boat into the ship’s side’, to allow persons to board the boat safely. This precaution is particularly important if the parent vessel has an adverse list, which would cause the boat to be slung in the vertical away from the ship’s side. The pendants are secured between the linkage directly under the floating block to the underside of the davit. The senhouse slip is held secure by a wooden pin, which will not rust or jam and can easily be broken to release. The reason the rope lashing is incorporated into the Boat fall Davit arm Welded lug Steel wire pendant Floating block Loose linkage Rope lashing Elongated shackle Senhouse slip Bowsing in tackle Figure 7.15 Use of tricing pendant. 191Boatwork make-up of the pendant is that it can be cut in an emergency. Tricing pendants should be released once the bowsing in tackles are secured. Survivors should then board while the weight of the boat is bowsed in. The tackles can then be paid out and released before lowering. Gripes These are constructed of steel wire rope that has a rope lashing and a bottle screw with senhouse slip incorporated in its length. The purpose of the gripes is to hold the boat firmly against its stowage chocks and keep it in a secured stowed position in the davits. There are several methods of griping the boats against the davit chocks, one system being shown in Figure 7.16. It will be seen that the gripe wire is secured to the trigger lever, passing over the gunwales of the boat and then being secured via lead sheaves to the inside foot of the davit. The gripes are cleared by compressing the two parts of the senhouse slip and clearing away the securing link. Once the slip and bottle screw are released, the gripe can be passed back over the boat and the end cleared. However, some gripes are interconnected to the trigger system, and the men in the boat clearing the gripes over the gunwales should in fact check and report that the triggers have fallen and the davits are clear to lower away. The cox’n in charge of the launching operation should also check that the securing end of the gripe does not fall under the lowering davit arm, causing buckling, or fouling the lowering operation. In re-securing the gripes the bottle screw arrangement will need to be opened up, in order to pass the senhouse slips. Once this is done, the gripes can be re-tensioned by use of the screw. A rope lashing is incorporated for the same purpose as with the tricing pendant, so that it may be cut in an emergency. LAUNCHING PROCEDURE Gravity Davits These davits (Figure 7.16) operate on the principle of the boat’s own weight doing the work to bring about the launch. The construction of the davits includes a safety device, usually a trigger arrangement attached to the gripes; and when launching, care should be taken to check that these triggers are cleared before proceeding. Gravity davits must be fitted with steel wire rope falls and operated by a controlled winch. The rate of descent of the boat is separately controlled by a centrifugal brake. A main ratchet type brake is also incorporated in the more modern designs, and it can hold the boat at any stage of lowering. This may be operated, in some cases, from inside the craft itself, so that the launching cycle can be carried out remotely, thus saving time once waterborne for taking on personnel. The majority of gravity davits are fitted with tricing pendants, and the boat must be equipped with means of bowsing in against the ship’s side to permit the removal of the pendants before embarking personnel. Floating block Plate link Loose linkage Gripe Davit arm Gunwale chock Trigger lever Griping sheave Tricing pendant Figure 7.16 Pivot gravity davit. 192 Seamanship Techniques The davits will successfully launch the boat against a 25° adverse list in the following way: 1. Two men should be ordered into the boat, to ship the plug and check that the painter is rigged in a correct manner. (Painter is passed inside the fall and outside everything else, and secured well forward.) Once all work inside the boat is complete, these two men should be seen to sit down in the boat and hold on to the lifelines. 2. The cox’n should check that the harbour pins are out. 3. The gripes should be slipped and any triggers checked to see that they are clear, the gripes being passed down to deck level clear of the boat. 4. A winchman must be ordered to stand by to lower the boat down to the embarkation deck. 5. Check that the overside is clear, then lower away by lifting the brake handle. The boat should descend from the davits until the tricing pendants take the boat’s weight and draw the boat into the ship’s side. 6. The bowsing in tackles should be rigged in such a manner that the downhaul is secured in the boat with a round turn and two half hitches, on the bight about the linkage on the end of the falls. 7. Have the two men in the boat slip the tricing pendants once both ends of the boat are securely bowsed in. 8. The remainder of passengers and boats crew should now be embarked, and seated as low as possible in the boat. 9. Ease out on the bowsing in tackles and allow the boat to come away from the ship’s side, then let go the tackles from inside the boat and throw them clear, back towards the parent vessel. 10. Order the winchman to lower the boat with a run. Ship tiller. 11. Unless release gear is fitted to the boat, it is more practical to lower the boat into a trough of a wave. As the crest of the wave brings the boat higher, this will allow the falls to become slack, which will in turn allow easy slipping from the lifting hooks. Once the falls are clear, the boat falls away from the ship’s side as the wave drops away. Should quick release gear be fitted to the boat being launched, then it would be more practical to slip the release mechanism as the boat takes the crest of a wave. As the wave drops away into a trough, so it takes the boat away from the ship’s side with it. The time of the boat becoming waterborne is the most critical, and many serious accidents have occurred in the past. The floating heavy blocks of the falls are a major cause of the accidents, as they are in the direct vicinity of the boat in the water and they oscillate wildly at head height. A prudent cox’n will endeavour to clear the area as soon as possible. An alternative means of reducing this danger is to secure light lines to the floating blocks of the falls and manning them by additional personnel on deck. Once the boat has slipped the falls, these blocks can [...]... will require considerable experience and use decisive judgement, once inside the line of surf Beaching under power, stern first, is slower and must generally be considered safer Use of the sea anchor over the bow with combined use of the boat’s engines should provide the required force to keep the bow end on to the direction of surf Pulling oars should be kept ready in the event of engine failure and... needs.The structure incorporates a ventilation system, a fire sprinkler system for the exterior, seat belts and a 40 H.P Westbeck, water cooled diesel engine Launching is achieved by a winch and single cable system from platform level An independent release from the fall being possible by operation of an offload release gear The launching and recovery of the capsule is operated by a 25 horsepower electric... their person, then board the raft keeping it stable Release the boarding flap and the bowsing lines and throw them into the entrance of the raft Check the overside is still clear and lower the life raft Cock the release hook by means of the operating lanyard when the life raft is close to the water surface (within about 10 feet) The raft should be automatically released once the raft becomes waterborne... manual release Should the vessel suffer a disaster and subsequently sink, then the release unit will automatically activate under the surface of the water, at not more than 4 m depth, when the pressure is sufficient to release the draw bolt Once the draw bolt is released, the web strap lashing no longer retains the raft canister in its cradle support The life raft is free to float to the surface, extracting... support the full weight of the laden boat Hoisting If the operation is taking place on a Class 1 passenger vessel, then the sequence of actions are made easier by the use of the rams horn lifting hook, a standard fitment in the emergency boats of passenger vessels However, where a single lifting hook is to be used, as with Class 7 vessels, then the method of recovery can be achieved in the following... section 1) Extreme care must be taken to ensure that the strop and 4 Walk back on the fall and secure linkage over the wire pendant on to lifting hook Detach pendant at davit head Figure 7.19 Boat recovery in heavy weather 198 Seamanship Techniques the wire pendant, together with any shackles used, are of sufficient strength to accept the weight of the fully laden boat The boat falls should be retrieved... helm, bring the boat head to wind and let fly the sheets Stream the sea anchor, steadying the boat’s head Lower the mainsail, and detach the yard strop from the traveller Lay the yard on the side benches, and clear the foot of the sail Secure the luff earring to the tack cringle Secure the leach earring to the clew cringle Gather up the foot of the sail and tie the reef points from forward to aft Rehook... waterborne and its weight is removed from the bearing surface of the hook by the buoyancy effects on the raft The painter should be cut or released and the life raft quickly manoeuvred away from the ship’s side Once clear of the immediate area life rafts should be joined together with about a 10 m length between to avoid snatching in a seaway Mills Atlas Release Hook In this release mechanism (Figure 8 .6) ... Where davit arms are recovered by power, safety devices shall be fitted which will automatically cut off the power before the davit arm reaches the stops in order to prevent overstress on the falls, unless the winch is designed to prevent such overstressing Falls shall be of rotation-resistant steel wire rope They should wind off the drums at the same rate when lowering and wind on to the drums evenly... should be released by slipping the manually operated senhouse slip.The raft container should then be manhandled to the launching position by the ship’s side If side rails are in position, these should be removed to facilitate the launch The painter from the raft should be checked to see that it is well secured to a strong point of the vessel Where a hydrostatic release unit is fitted, the painter and . the securing link. Once the slip and bottle screw are released, the gripe can be passed back over the boat and the end cleared. However, some gripes are interconnected to the trigger system, and. the ultimate strength of materials used, assuming the mass of the boat is equally distributed between falls. Painter Release Every lifeboat shall be fitted with a release device to enable the. between ships. Buoyant (becketed) Lifeline Each lifeboat will be provided with a buoyant lifeline becketed around the outside of the boat, except in the vicinity of the rudder and the propeller.