The Inflatable Liferaft
	See also: 'Understanding Human Behaviour in Emergencies'
	The Liferaft
	Liferafts vary in size from a 4-man up to a 42-man. The maximum weight limit laid down by the Department of Transport is 400 lbs. The liferaft will either be in a Canvas or Neoprene Valise or a Glass-Fibre Stowage Container. The advantage of the Glass-Fibre Container is that it requires no additional stowage and is simply pushed over the side, whereas the Valise requires a Stowage Box either of wood or metal and the raft has first to be lifted out of its box before launching, which might be a waste of valuable time in an emergency. Regarding dimensions, a 25-man liferaft, when inflated, is over 14 feet diameter and over 7 feet high, yet this raft with full rations and equipment is packed in a container which is approximately 64 inches long X 23 inches diameter. The Hull consists of two separate buoyancy tubes generally one on top of the other. The floor is double and is fixed to the lower buoyancy tube and pumped up by a hand pump. On the upper buoyancy tube are the arch tubes which support the canopy of the raft. The arch tubes are inflated automatically from the upper buoyancy tubes and are fitted with non-return valves so that they will not collapse should the upper buoyancy tube be punctured. Some liferafts have a centre pillar for supporting the canopy, and this also inflates automatically.
	Inflation
	This is by a gas cylinder which is located under the lower buoyancy tube. The pressure of the gas in the cylinder is over 2000 lbs. p.s.i. but the pressure in the buoyancies when inflated is approximately 2 lbs. p.s.i. The liferaft is inflated by hauling on the painter which, when it is at its full extent triggers off the plunger which is forced through the seal of the gas bottle and full inflation taken from ten to sixty seconds, depending on the temperature. When the liferaft is fully inflated two openings in the canopy will be found for boarding in liferafts for more than six persons. Each opening has a boarding ladder and the openings can be closed with the weather sheets, to give complete shelter.
	Fittings
	Both on the outside and inside of the raft there are lifelines. Stabilisers are fitted underneath the lower buoyancy tubes and automatically fill with water when the raft inflates; they help to steady the raft and cut down drift. Liferafts are fitted with electric light, one outside, and in the newer models, one inside as well. These lights are generally worked by sea-water batteries. In some makes the battery is attached to the lower buoyancy tube, and if a raft is launched during daylight hours the battery should be removed and the water shaken out. Stow the battery where no moisture can get at it, and then replace it in its proper position at nightfall.
	Rain Catchment Tubes
	On the underneath side of the canopy there are rubber tubes fitted with plugs. Rain falling on the canopy will flow down the tubes and drinking-water can be collected in empty water tins or polythene bags in which rations, etc., are packed.
	Liferaft: Click for a larger Image All important items in the raft are clearly marked, and include: Inflate/Deflate Valve. Fitted on the insides of the buoyancy tubes, canopy support and floor for topping-up the pressure in the tubes or inflating the floor by means of the bellows provided in the emergency pack: They are fitted with plugs and a special deflating tool. Relief Valves. Fitted on the buoyancy tubes to relieve any excess pressure which might build up. They are fitted on the outside of the raft so that the excess gas exhausts to atmosphere and not into the liferaft. Rescue Line. A buoyant heaving line with a rubber ring for throwing to survivors in the sea. Knife. Generally located in a pocket on the main buoyancy tube just inside the entrance. Sea-Cell Battery. With an arrow showing location of battery. In each liferaft will be found an Instruction Book giving a detailed plan of the raft instructions on repairing leaks, and useful hints on survival. There is a pair of paddles to enable survivors to get clear of a sinking ship, etc. The paddle protection pieces can be used as sponges for mopping up. Emergency Pack. Contents are listed on the outside. Pyrotechnics, water-food, first-aid kit and other items as required by the Department of Transport are in this container. The liferafts on Class II and Class IIA vessels do not carry Emergency Packs, but one in six of the liferafts is fitted with pyrotechnics and a signaling torch. Do not use Distress Signals until there is reason to believe that they may be seen. Reader manufacturers' printed instructions before firing. All liferafts carry an equipment bag, the contents of which are as follows: Repair Outfit: With full instructions for carrying out repairs. Leak Stoppers: In various sizes. These are screwed into a hole until such time as a repair can be carried out. Sea Anchor: Is lashed to the outboard lifeline with thread, at one of the canopy openings. In round rafts the painter of the sea-anchor is made fast midway between the two openings and when riding a sea there is no fear of water entering the raft if the side is snubbed down. In oblong rafts the strong point of the sea-anchor is at one of the ends, and it is suggested that when the sea-anchor is streamed the canopy opening should be kept closed in bad weather.
	Stowage
	There are various forms of stowage. Boxes for rafts in Canvas, and deck cradles or launching ramps for those in Glass-Fibre Containers. The stowage position should be clear of gangways and gear and preferably amidships, and the stowage should be in such a form that liferafts can be easily transferred to either side of the vessel. For a vessel carrying one liferaft, stowage on the centre line is preferable. Liferafts should always be stowed right way up and the painter made fast to the ringbolt on the stowage box or cradle, during shipment liferafts should be very carefully carried. On no account are they to be rolled. Click for a larger Image
	Maintenance
	Liferafts must be sent to an approved service station for survey once every twelve months, but there are one or two maintenance jobs that can be carried out on board. After heavy weather, examine liferafts in stowage boxes to make sure there has been no movement to cause chafing. If the liferaft does not fit snugly, put in some packing. The securing strops round Glass-Fibre containers should be examined for wear, and lashings checked. Glass-Fibre Containers should be kept clean by washing down with Soogee - never hose down, as the pressure in some deck hoses can be very powerful and water might penetrate the sealing strip. Examine the bands and sheer pins for rust, and grease the pins if necessary. If a container is accidentally broken or cracked, put a patch on immediately. A liferaft must always be 100 per cent efficient, and if it has suffered damage or if there is any doubt about its general condition, get in touch with your nearest Service Station on arrival in port. Liferafts are surveyed by a Department of Transport Surveyor and sealed before leaving the factory or service station. The metal seals should be left intact.
	Launching
	Before launching a liferaft make sure that the end of the painter is fast to a strong point inboard. It is preferable to haul off sufficient painter to allow for free board before throwing the raft overboard. When the valise or containers is afloat, haul off remainder of painter until raft bursts out of its valise or container.
	Log-Cards
	Every liferaft has a log-card which should be kept with the ship's papers and be available at all times for inspection by Board of Trade Surveyors. When a liferaft is sent ashore for survey the log-card must be forwarded to the Service Station which will enter particulars of the work carried out and the date. Every entry is certified by a Board of Trade Surveyor.
	Facts About Liferafts
	Hundreds of lives have been saved by liferafts, and in several cases the weather was such that a conventional lifeboat would have been useless. Two rescues are of particular interest, as they prove the capabilities and sea-worthiness of the inflated liferaft: The first concerns a British Trawler which struck a rock off Iceland. A full gale was blowing and a very heavy sea running. As the vessel struck, she was swept by a sea which carried away the starboard lifeboat. The port lifeboat was lowered, but was smashed up alongside. The liferafts were then launched and the whole crew embarked and were picked up about an hour later by a Fishery Patrol Vessel. A second illustrates the strength of a liferaft: A small fishing vessel struck a reef about 200 yards off a point on the West Coast of Scotland, in very heavy seas with a full South Westerly gale blowing. The vessel immediately started to break up and the crew launched and boarded their 6-man liferaft. There was a succession of reefs between them and the beach. The first wave swept them on the nearest reef where they were bumped about until the next wave swept them across another reef, and so on until the raft was washed up on the beach and the six men stepped out unharmed. The liferaft, apart from a few scratches, was undamaged. A liferaft in its valise or container is more liable to damage than when it is inflated, so when moving a liferaft, always handle with care. When hoisting a liferaft in a valise, do not put a sling round it but use a cargo tray. All liferafts are capable of carrying double the numbers of which they are certified. With every new liferaft, manufacturers issue 'Abandon Ship' cards for attaching to bulkheads, giving full launching instructions, etc. These should be fixed in prominent positions on board every ship carrying liferafts.
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