It is a unit fitted to secure the liferaft such that if the ship sinks it will automatically release the life raft at a depth of not more than 4m.
How does HRU work?
- Once ship starts to sink, and when it sinks upto 4 meter the water pressure will activate sharp knife in H.R.U.
- It will cut the securing rope around the canister or container of the raft, and now raft will float free.
- Now ship will further sink, the painter line will stretch and it will inflate the raft.
- Now due to increase in buoyancy, it will break the Red weak link at around 2.2 KN± 0.4 and life raft will be on surface of water now.