Hydrostatic Release Units
The Hammar Hydrostatic Release Unit
White strong rope of Hammar H20 secured to deck or liferaft cradle and attached to liferaft lashing with a sliphook. Liferaft painterline shackled to weak-link and around strong white rope.
If the ship sinks, the water pressure will, within 4 metres, activate the sharp knife which cuts the strong rope and the liferaft will float free.
As the ship sinks, the liferaft painterline will be stretched and the liferaft starts to inflate.
Red weak link breaks and survivors can board the inflated liferaft.