A life raft is typically an inflatable boat which can be stored on a larger ship for use in emergency - for example if the larger boat sinks. They can be small, carrying one or two people, or very large with a capacity of around 50. Low weight, and small packing size are important whatever the capacity for passengers - they are often vacuum packed.
The following criteria are important to a life raft's construction:
- It should withstand being dropped into the sea from an appropriate height. This should be at least the height at which it is stored on the larger vessel. The impact from the drop mustn't affect the operation of any on-board equipment.
- It should inflate automatically from a compressed gas chamber with a non-return valve. A canopy to provide shade should automatically erect.
- It should withstand people jumping into it from at least 4 meters above sea-level with and without the canopy erect.
- It should withstand all sea conditions for a protracted time - around 15 days is reasonable.
- It should withstand punctures by incorporating at least two separate inflation chambers. Each chamber should be capable of supporting all passengers and equipment on its own, although their movement may be restricted in this case.
- It should withstand being towed at a reasonable speed with all passengers and equipment on board.
A life raft should have the following equipment:
- Motion - anchors, paddles.
- Signalling - parachute flares, smoke signals, torch, signalling mirror, whistle or other audible signalling device.
- Attention - bright beacon on the top of the canopy, radar reflector.
- Safety - life belts, first aid kit.
- Buoyancy - bailer, sponges, repair kit, pump.
- General - knife, seasickness medication and bags.
All equipment, where possible, should be waterproof and buoyant. No equipment should have sharp edges, with the exception of the knife (which should be stored and handled very carefully).
A solar still may also be carried as a source of fresh water.