How lifeboat capacity is decided
The number of persons allowed in a lifeboat is not guessed on the jetty. It is the certified figure on the boat’s nameplate and in the Record of Equipment. Older open boats used a cubic capacity formula. Modern enclosed boats are type-approved with a seating plan and a maximum weight. SOLAS also requires enough boats or MES on each side for the total number of persons on board.
How this calculator works
Cubic capacity is estimated as Length × Breadth × Depth × 0.6, a simple block-coefficient style estimate. Persons are then estimated at 0.283 m³ per person, an old rule of thumb. The result is for training only. Never change the posted capacity of a survival craft from this page.
Who should use it
Useful for cadets learning LSA. For drills and abandon-ship, use the number painted on the boat and the Muster List.