🔍 Key Concepts
• Hydrostatic release unit (HRU) is the device that automatically releases the liferaft when submerged to a certain depth (about 4 meters).
• The HRU is installed between the raft’s securing strap and the ship/deck – not on the raft body itself.
• The weak link and painter line are separate items: the weak link is designed to break, and the painter leads to the raft canister.
💭 Think About
• Look at which numbered part is a mechanical device mounted low, near the deck/cradle, that would sense water pressure, rather than a simple rope or label.
• Identify which numbered item connects the strap that holds the raft down to the deck or cradle, since that’s where the hydrostatic release must sit.
• Ask yourself: which item, if it were removed, would prevent the raft from being automatically freed when the ship sinks, even though the painter might still be attached?
✅ Before You Answer
• Verify which number points to a metal mechanism, not a rope, pad eye, or canister label.
• Confirm that this part is located between the securing strap and the deck/cradle, consistent with how a hydrostatic release is installed under SOLAS/46 CFR requirements.
• Make sure you can distinguish the weak link in the painter line (small sacrificial connector in the rope) from the HRU (pressure-activated release on the securing strap).