Hydrostatic release unit
The hydrostatic release unit that frees liferafts, EPIRBs and VDR float-free capsules when a ship sinks, and the servicing and expiry dates checked at survey.
A hydrostatic release unit frees a float-free item from its bracket when a sinking ship reaches a set depth, so that a liferaft, an EPIRB or a voyage data recorder float-free capsule can rise to the surface. SOLAS Chapter III and the LSA Code set the requirements for liferaft float-free arrangements.
The unit carries an expiry or service date, and annual surveys and the VDR and EPIRB annual tests check that float-free arrangements are in date.
The full article will cover the types of unit, the depth of release, disposable and serviceable designs, the weak link on liferaft installations, and the survey and port state control checks.