Hydrostatic Release Unit
(3.1) Construction
A hydrostatic release unit used in float-free arrangements shall be so constructed that—
(1) the materials used are compatible so as to prevent malfunction of the unit; galvanising or other forms of metallic coating on parts of the release unit will not be accepted;
(2) it has drains to prevent the accumulation of water in the hydrostatic chamber when the unit is in its normal position;
(3) each part connected to the painter system has a strength not less than that required by the painter;
(4) it can readily be removed for replacement or annual servicing.
(3.2) Materials and Components
Materials and components shall be corrosion-resistant and not affected by seawater, oil or detergents.
(3.3) Performance
A hydrostatic release unit shall—
(1) function properly throughout an air temperature range of −30 degsC to +65 degsC;
(2) function properly throughout a seawater temperature range of −1 degsC to +30 degsC;
(3) automatically release the liferaft at a depth of not more than 4 metres;
(4) not release prematurely when seas wash over the unit;
(5) be capable of releasing a liferaft when the stowage is—
(1) horizontal;
(2) tilted 45 degs and 100 degs with the hydrostatic release unit at the upper side;
(3) tilted 45 degs and 100 degs with the hydrostatic release unit at the lower side;
(4) vertical.
(3.4) Marking
A hydrostatic release unit shall be marked permanently on its exterior with a means of identifying its type, serial number, depth at which it will release, and in addition if of a type which—
(1) requires annual servicing with its date of manufacture and a small plate permanently attached to the unit for recording the date of servicing,
(2) is disposable, with the date at which it must be replaced.
(3.5) Instructions and Information
Instructions and information shall be provided in English in a clear and concise form and shall include the following—
(1) general description of the unit;
(2) installation instructions;
(3) any on board maintenance requirements;
(4) servicing requirements.