Life Raft

What Distinguishes a Life Raft From a Lifeboat

A life raft has no propulsion, steering or rigid hull of its own: it is a flexible, buoyant chamber that inflates from a compressed gas cylinder in seconds and is either launched by a hydrostatic release unit that fires automatically as the ship sinks, or thrown and inflated by hand. Against a lifeboat, which can be steered clear of the ship and motor toward rescue, a life raft simply keeps survivors afloat, dry and stocked with rations until help arrives, which is why SOLAS treats the two very differently in terms of where each is required.

Main Components

Buoyancy chambers

Two or more independent inflatable tubes, so damage to one chamber does not deflate the whole raft, inflated by CO2 or a CO2/nitrogen mixture from a cylinder fired automatically on launch.

Canopy

A self-erecting cover, usually double-skinned, that shelters occupants from wind, spray and sun and carries a reflective and high-visibility exterior for search and rescue.

Painter line and hydrostatic release unit

The painter connects the raft to the ship and triggers inflation when pulled; the hydrostatic release unit releases the raft's cradle automatically once the ship has sunk to a set depth, so a raft launches even if no one reaches it in time.

Survival equipment pack

Rations, drinking water, seasickness tablets, first aid kit, hand flares, a radar reflector or SART, a bailer, a sea anchor, and repair clamps for the buoyancy tubes, packed to a standard set out in the SOLAS equipment schedule for the raft's pack type, A or B, differing mainly in cold-weather items.

Selection and Sizing

Capacity is fixed by the number of persons the raft is rated for, stated on its container, and the ship's abandon-ship arrangement must provide capacity for the full complement with the required margin allowed for one side being unusable. Pack type, SOLAS A for ocean-going and SOLAS B for less demanding trades, and container material, fibreglass for davit-launched or deck-stowed rafts and specific low-temperature-rated fabric for cold trades, follow the vessel's trading area.

Regulations and Class

SOLAS Ch. III sets the number, capacity and stowage of life rafts required by ship type and trading area, and requires each raft to be serviced ashore at an approved service station at intervals normally not exceeding twelve months, with the hydrostatic release unit itself also carrying a limited service life stamped on the unit. Class and flag state surveys check current service due dates on every raft container as a matter of course, and an overdue service date is one of the more common port state control detention items.

Typical Faults

• Hydrostatic release unit past its expiry date means the raft will not release automatically if the ship sinks and no one reaches the deck in time.
• Cracked or degraded container lets water into the pack, which can corrode the CO2 cylinder valve or spoil rations undetected between services.
• Painter line chafe or an incorrect securing point means the raft either fails to inflate on launch or, worse, stays attached to a sinking ship.
• An overdue annual service invalidates the safety equipment certificate entry for that raft and is a routine detention item at port state control.

What to Look for in a Supplier

• An approved service station network that actually covers the ship's trading ports, since a raft due for service where no station exists means downtime or a costly ship-to-shore swap.
• Pack type and cold-weather rating matched to the actual trading area, not the cheapest standard option.
• A clear documentation trail from manufacture through every service, since a raft with a broken service history is difficult to defend at a port state control inspection.

Check the hydrostatic release unit's expiry date separately from the raft's own service due date at every round: the two are stamped on different components and it is a common miss to renew one and overlook the other.