Equipment Guide · Lifeboat Davits & On-Load Release
A lifeboat launch is a controlled fall: the boat's own weight rolls the davit arms out and pays the falls off the winch — no ship's power anywhere in the chain. What the machinery really manages is the one moment that has killed seafarers in drills: opening the hooks. Tap a step or press "Play" to follow the load path from winch to hook — then take the simulator through a launch, and see what happens when the release comes before the water.
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The rule sizes the fall against the escape: the higher the boat hangs, the faster it must be allowed to come down, so that a fully loaded boat always reaches the water in roughly half a minute. Worked example — davit head 25 m above the lightest waterline: S ≥ 0.4 + 0.02 × 25 = 0.9 m/s, so the drop takes about 28 seconds. The centrifugal brake is what holds the boat near that speed automatically — the faster the drum turns, the harder it grips — which is exactly why you should not "help" it: lifting the deadman fully and letting the governor work gives a smooth, steady run; snatching the brake open and shut hammers the wire, the sheaves and the hooks with shock loads they were never sized for.
Press Start, then lift the brake (+ on the winch brake) and run the sequence: lower — WATERBORNE — slip FPDs — release. Or pull the release early, and see what the interlock, the pin and the strops each do.
About the simulator
Lower the boat and get it away — in the right order. The winch brake starts and stops the descent; the hydrostatic interlock keeps the release lever locked until the keel is wet; the safety pin defeats that interlock; the FPD strops are the last line if a hook opens early. The correct sequence is: lower → waterborne → slip FPDs → release. Pull the release early with the pin out and no FPDs, and you will see exactly why the rules exist.
Interlock logic — pin removed at height = interlock DEFEATED · keel wet = interlock FREE · release at height, no FPD = free fall.
The lever, the pin and the strops are all evaluated live: pulling the lever while the interlock is locked does nothing — the refusal is the design working. Remove the pin and the same pull opens both hooks under full load at any height. With FPDs rigged a premature release drops the boat centimetres onto the strops with a shock load; without them it falls free until the water stops it.
Working principle — explained in our own plain words with our own schematic from general marine knowledge (not copied from any OEM manual). Conceptual; varies by ship/model. Reviewed and verified by a Master Mariner.