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Annual and Five-Yearly Thorough ExaminationLesson 4 of 8

Release gear and the release tests

How release gear is examined each year, and how the on-load, off-load, free-fall and davit-launched liferaft release tests are carried out.

16 minutes · For signed-up learners, free · Rules checked 20 October 2026 · Reviewed by the Lifeboat Inspections technical team

Technical drawing of a generic on-load release hook

In plain words

The release gear is what lets go of the boat once it is in the water. Failures of release hooks have caused more deadly lifeboat accidents than any other part of the system. If a hook opens too early, the boat falls. If a hook is not fully closed after use, it can open later when nobody expects it.

At the annual examination, a certified technician first examines the gear: the handle and its linkages, how much play there is in the moving parts, the hydrostatic interlock that senses when the boat is afloat, the cables, and the way each hook is fixed to the boat. Then the gear is tested for real. The on-load release is tried with the boat just touching the water, so the hooks still carry its weight. The off-load release is tried with the boat fully afloat. Free-fall boats and liferaft hooks have their own tests. After every release, the technician checks that each hook is completely reset.

Key points

  • Release gear is examined after the annual winch brake test with the empty boat (MSC.402(96) §6.2.4).
  • The examination covers activation devices, excessive free play, the hydrostatic interlock, control and release cables, and hook fastening (MSC.402(96) §6.2.4.1–.5).
  • The on-load test is done with the boat partly in the water, its mass substantially supported by the falls, without triggering the hydrostatic interlock (MSC.402(96) §6.2.5).
  • The off-load test is done with the boat fully waterborne, and the final turning-in is done with nobody on board (MSC.402(96) §6.2.6).
  • Free-fall release gear is tested with the test arrangement, without launching, and the test is repeated with the back-up release (MSC.402(96) §6.2.7; LSA Code 4.7.6.4).
  • A davit-launched liferaft hook is released manually with 150 kg and automatically with a 200 kg dummy weight (MSC.402(96) §6.2.8).

Continue this lesson free

The full lesson, the interactive tool “Put the release test steps in order” and the check are open to signed-up learners. It's free, takes a minute, and opens every lesson in all three courses.

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Sources

  1. Requirements for maintenance, thorough examination, operational testing, overhaul and repair of lifeboats and rescue boats, launching appliances and release gearIMO resolution MSC.402(96), 19 May 2016
  2. Amendments to SOLAS chapter III, regulations 3 and 20IMO resolution MSC.404(96), 19 May 2016, in force 1 January 2020
  3. Adoption of the International Life-Saving Appliance (LSA) CodeIMO resolution MSC.48(66), 4 June 1996
  4. Amendments to the LSA Code (release mechanisms, 4.4.7.6)IMO resolution MSC.320(89), 20 May 2011, in force 1 January 2013
  5. Amendments to SOLAS (regulation III/1.5, replacement of on-load release mechanisms)IMO resolution MSC.317(89), 20 May 2011
  6. Amendments to the LSA Code (hook reset, lowering speeds)IMO resolution MSC.554(108), 23 May 2024, in force 1 January 2026
  7. Revised guidelines on safety during abandon ship drills using lifeboatsIMO MSC.1/Circ.1578/Rev.1, 6 July 2026
  8. ABS Regulatory News: Brief MSC 111ABS, 22 May 2026
  9. Shipping Circular No. 8 of 2026 (resolutions adopted at MSC 111)Maritime and Port Authority of Singapore, 27 August 2026
  10. Review of Lifeboat and Launching Systems' AccidentsMAIB Safety Study 1/2001, 1 February 2001
  11. Investigation report: lifeboat release on board Harmony of the Seas, 13 September 2016BEAmer, published by the Bahamas Maritime Authority, May 2017
  12. Risks in launching and recovery of lifeboatsSteamship Mutual
  13. MGN 560 (M+F) Amendment 2: requirements for life-saving appliancesUK Maritime and Coastguard Agency, 10 December 2021

Free awareness training. Lifeboat Inspections is not authorised to issue training certificates, so none is given, and this course is not a qualification. It doesn't replace STCW survival craft training, manufacturer training or MSC.402(96) technician certification. The manufacturer's manual and your flag's rules always come first.