There are two types of lifeboat releasing mechanisms- on load and offload. These mechanisms release the boat from the davit, which is attached to a wire or fall by means of a hook. By releasing the hook the lifeboat can be set free to propel away from the ship.

The offload mechanism releases the boat after the load of the boat is transferred to water or the boat has been lowered fully into the sea. There is a hydrostatic piston unit provided at the bottom. the piston is connected to the operating lever via a link. As the ship becomes waterborne, the water pressure will move the hydrostatic piston up.

https://www.marineinsight.com/maritime-law/types-of-lifeboat...

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