Technical Circular No: 060/2021

AMSA Safety Alert 02/2021 Reg. – Correct use of Hydrostatic Release Units (HRUs).

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1. Australian Maritime Safety Authority (AMSA) vide Safety Alert No. 02/2021 has informed that, over 100 deficiencies in relation to deficient HRU arrangements on liferafts and float-free EPIRBs were issued by AMSA in the year 2021.

2. In this regard, it is to be noted that the HRU used on life raft securing devices cuts through a cord that fastens the securing straps. The life raft container has enough inherent buoyancy to float free from its cradle and in doing so, pulls out the life raft painter to inflate the raft. The painter is attached to a weak link that is designed to break once the raft has inflated.

3. It is important that the HRU and weak link are correctly installed. If the painter is not attached to the weak link correctly, the raft may not inflate, or may not release from the sinking vessel.

4. Accordingly care must be taken to ensure that the securing straps on a life-raft canister will release when the HRU activates, and that the liferaft painter is attached to the HRU weak-link.

5. Similarly, the HRU on a float-free EBIRB should be checked to ensure it is installed correctly. No additional lashings should be used on the EPIRB housing – this can prevent the housing cover from releasing when the HRU activates, stopping the EPIRB from floating free.

6. Further, HRUs can be serviceable or disposable. Re-useable HRUs must be serviced annually by the manufacturers authorised service agent to ensure they will work when required. Disposable HRUs have a service life once installed and must be replaced once they reach their expiry date. 

7. Ship owners/ managers and masters are advised to be guided by above and ensure that hydrostatic release units are installed correctly and that life-raft painters are connected to the HRU weak link.



This Technical Circular and the material contained in it is provided only for the purpose of supplying current information to the reader and not as an advice to be relied upon by any person. While we have taken utmost care to be as factual as possible, readers/ users are advised to verify the exact text and content of the Regulation from the original source/ issuing Authority. 

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