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Lifeboats and davitsLesson 2 of 9

Anatomy of a lifeboat, davit, winch and release gear

You will be able to trace the load path from davit to hook and name what each part must do under the LSA Code, and how each part fails.

15 minutes · Open to everyone · Rules checked 20 October 2026

Start here

A lifeboat hanging from its davit is one chain of parts, and it is only as strong as its weakest link. On 10 February 2013, during a drill alongside in Santa Cruz de La Palma, the forward fall wire of lifeboat No. 9 on the passenger ship Thomson Majesty parted while the boat was being hoisted with eight crew on board. The boat swung on its aft hook, that end failed too, and the boat fell about 20 m. Five crew died. Malta’s investigators found that the wire had parted at a site of corrosion inside the rope, where it looked dry and ungreased.

Nothing in that boat was exotic. A wire, a sheave, a hook. To inspect or service a lifeboat system you need a clear picture of every link in the load path, what the LSA Code demands of it, and how it typically fails. Click each numbered part below.

Try it

A davit-launched lifeboat and its launching appliance

In plain words

Think of the system as five links between the ship and the sea.

  1. The davit swings the boat out over the side. Most ships use gravity davits: the boat’s own weight pulls the arms out and down when the brake is lifted. No ship’s power is needed.
  2. The falls are the steel wire ropes that run from the winch, over sheaves at the davit heads, down to a block above each end of the boat.
  3. The winch holds the wire. Its brake is on by default. Lifting the brake lever lets the boat lower under gravity, and a governor keeps the speed safe. A hand crank or electric motor hoists the boat back up.
  4. The hooks join the falls to the boat. When the boat is afloat, the coxswain pulls one handle and both hooks open, so the boat can motor away. In an emergency, the hooks can also be opened while the boat is still hanging (“on-load”), but only through a deliberate, protected action.
  5. The boat itself: hull, canopy, engine, steering, water spray or air supply on tanker boats, and the equipment inside.

If any link fails while people are inside, the boat falls, so every link has a safety factor, a test and an inspection interval.

Types you will meet: on cargo ships, totally enclosed lifeboats on each side, or a single free-fall lifeboat over the stern. Tankers carrying low-flashpoint cargoes carry fire-protected lifeboats with a water spray system, and ships carrying toxic cargoes carry lifeboats with a self-contained air supply. Rescue boats and fast rescue boats are covered in lesson 7.

In detail

The load path and its design factors

Link LSA Code rule Value
Davit structure 6.1.1.6 safety factor on maximum working load At least 4.5
Falls, suspension chains, links, blocks 6.1.1.6 At least 6
Whole appliance except winch brakes 6.1.1.5 factory static proof load At least 2.2 times the maximum working load
Winch brake 6.1.2.5 static test / dynamic test at maximum lowering speed 1.5 times / 1.1 times the maximum working load
Hydrostatic interlock 4.4.7.6.15 Safety factor at least 6
Release operating cables 4.4.7.6.16 Safety factor at least 2.5

These are design values. In service, the boat is tested empty every year and at 1.1 times fully loaded every five years (lessons 4 and 5).

Launching appliance rules worth knowing by heart

  • Gravity or stored power only. The appliance must not depend on anything but gravity or stored mechanical power independent of the ship’s power to launch the boat, both fully loaded and light (LSA Code 6.1.1.3).
  • One person, two positions. Lowering must be possible by one person from the deck, who must be able to see the boat, and from inside the boat (6.1.2.2).
  • Brake on by default. Manual brakes must always be applied unless the operator, on deck or in the boat, holds the control in the “off” position (6.1.2.12). This is the “dead man” principle; a brake lever tied up with rope defeats it.
  • Speed limits. The fully loaded boat must lower at least at S = 0.4 + 0.02H metres per second, where H is the height from davit head to the waterline at the lightest sea-going condition (6.1.2.8). For equipment installed on or after 1 January 2026 the minimum is capped at 1.0 m/s and the maximum is set at 1.3 m/s unless the Administration accepts otherwise (as amended by MSC.554(108)). The empty boat must lower at no less than 70% of the required speed (6.1.2.9).
  • Recovery. Hand gear must be provided for recovery, and its handles must not turn when the boat is lowered or hoisted by power (6.1.2.6). Where davit arms are recovered by power, limit switches must cut the power before the arms hit the stops (6.1.2.7).
  • Hanging off. A lifeboat launching appliance must have a means of hanging off the boat to free the on-load release gear for maintenance (6.1.2.13). Hanging-off pennants are for maintenance, not for drills.

How each part fails

Part Typical failure Where to look
Davit Seized pivots and rollers, corrosion at foundations, cracked welds, bent arms after a heavy stop Pins, tracks, foundations, limit switch arms
Sheaves Seized bearings, grooves worn to the wire’s diameter Turn by hand when unloaded, check groove profile
Falls Internal corrosion and broken wires where the rope rests in sheaves; wrong grease; wrong termination Lay the wire out, clean, inspect the stationary sections
Winch Worn or oil-soaked brake linings, governor faults, remote release wire snagging Brake test results, linings, remote wire run
Release gear Hook not fully reset, worn cam, seized or stretched cables, corroded hook foundations Reset indicators, free play, cable runs, keel shoe bolts
Boat Water in buoyancy foam (weight growth), cracked GRP, failed engine start Weight records, hull, engine log

The release gear in more detail

The LSA Code (section 4.4.7.6, rewritten by resolution MSC.320(89) in force from 1 January 2013) requires every davit-launched lifeboat to have two release capabilities:

  • Off-load (normal) release opens the hooks when the boat is waterborne or there is no load on them, without crew having to pull the lifting ring off the hook by hand.
  • On-load release opens the hooks with load on them. It must have a hydrostatic interlock, or another means to make sure the boat is waterborne, with a protected override for emergencies. The protection must be something you deliberately break, such as a glass cover; a label or thin wire seal is not enough.

A correctly designed hook, once reset, stays closed with any load from 0% to 100% of its safe working load, with up to 10 degrees of trim and 20 degrees of list. Lesson 6 covers the hook rule that forced older designs off ships.

The boat

The LSA Code’s general lifeboat requirements include an engine that runs for at least 5 minutes after starting from cold with the boat out of the water (4.4.6.3), a propeller that can be disengaged, with ahead and astern (4.4.6.5), and a speed of at least 6 knots fully loaded in calm water, with fuel for 24 hours (4.4.6.8). Lifeboats with a self-contained air support system must keep the air breathable for at least 10 minutes with all openings closed, without the inside pressure exceeding outside by more than 20 hPa (4.8). Fire-protected lifeboats must protect their occupants in an oil fire for at least 8 minutes (4.9.1).

Work it out

What the rules say

  • LSA Code paragraph 6.1.1.6 requires a minimum factor of safety of 4.5 for structural members of launching equipment and 6 for falls, suspension chains, links and blocks, based on the maximum working load and ultimate strength.1
  • LSA Code paragraph 6.1.2.5 requires winch brakes strong enough for a static test of at least 1.5 times and a dynamic test of at least 1.1 times the maximum working load at maximum lowering speed.1
  • LSA Code paragraph 6.1.2.12 requires manual brakes to be “always applied unless the operator”, on deck or in the boat, holds the control off.15
  • LSA Code paragraph 6.1.2.3 requires falls of rotation-resistant and corrosion-resistant steel wire rope.1
  • SOLAS regulation III/20.4 requires falls to be inspected periodically “with special regard for areas passing through sheaves”, and renewed when necessary or at intervals of not more than 5 years, whichever is earlier.2
  • LSA Code paragraph 4.4.7.6, as amended by MSC.320(89), requires on-load release to need multiple, deliberate and sustained action, a protected hydrostatic interlock override, and a hook that cannot open from wear, misalignment or unintended force from 0% to 100% of safe working load.3
  • LSA Code paragraph 6.1.2.13, added by MSC.218(82), requires a lifeboat launching appliance to have a means of hanging off the lifeboat to free the on-load release gear for maintenance.5
  • LSA Code paragraph 6.1.2.8, as amended by MSC.554(108) for equipment installed on or after 1 January 2026, sets the minimum lowering speed at S = 0.4 + 0.02H or 1.0 m/s, whichever is less, and paragraph 6.1.2.10 a maximum of 1.3 m/s unless the Administration accepts otherwise.6
  • LSA Code paragraph 4.4.6.8 requires a fully loaded lifeboat to make at least 6 knots in calm water and carry fuel to do so for at least 24 hours.4
  • SOLAS regulation III/31.1 requires cargo ships to carry totally enclosed lifeboats on each side or a free-fall lifeboat over the stern, each with liferafts, sized for everyone on board.7

Flag and class notes

  • Bahamas (Marine Notice 82) accepts, notwithstanding LSA Code 6.1.2.3, falls that are not rotation-resistant if they match the launching appliance specification and the davit manufacturer’s recommendation, but single falls must be rotation-resistant. Stainless steel falls follow the same rules as galvanised falls unless the manufacturer states a longer marine service life.8
  • Liberia (Marine Notice SAF-005) requires fall securing arrangements approved by class and the maker, and does not accept bulldog (cable) grips as primary load-bearing terminations; any found must be replaced immediately.9
  • Class: the davit and winch are type-approved equipment. At the annual survey the class surveyor examines each survival craft including the on-load release mechanism and hydrostatic lock, and the embarkation and launching appliances, normally by lowering each boat to the embarkation position.10

Key numbers

What Value
Davit structural safety factor At least 4.51
Falls, blocks and links safety factor At least 61
Factory static proof load of launching appliance 2.2 times maximum working load1
Winch brake design tests 1.5 static, 1.1 dynamic times maximum working load1
List and trim the appliance must launch against 20 degrees list, 10 degrees trim1
Minimum lowering speed, fully loaded 0.4 + 0.02H m/s (capped at 1.0 m/s for equipment installed from 1 January 2026)16
Maximum lowering speed, equipment installed from 1 January 2026 1.3 m/s unless the Administration accepts otherwise6
Falls renewal At least every 5 years2
Hydrostatic interlock / release cable safety factor 6 / 2.53
Lifeboat speed and fuel 6 knots fully loaded, 24 hours4

What inspectors find

  • Signs of disuse. The IMO port State control procedures tell officers to look for paint accumulation, seized pivot points, absent greasing and the condition of blocks, falls and the hook attachment to the hull.11
  • Falls corroded inside. The Thomson Majesty fall wire parted where it had corroded internally and looked dry; investigators also found it had not been fitted to the manufacturer’s specification and had been greased with the wrong product.12
  • Hooks. In the MAIB’s ten-year review, hooks caused 7 of the 12 deaths, and winches caused the most incidents (32 of 80).13
  • Lifeboats detained. Lifeboats were the third most frequent detainable deficiency in the Tokyo MOU region in 2025, with 152 cases.14

Questions people ask

Why is a gravity davit preferred?

Because it works with the ship blacked out. The LSA Code requires launching by gravity or stored mechanical power independent of the ship’s power supplies, in both the loaded and light condition.

What is the difference between off-load and on-load release?

Off-load release only opens the hooks when the boat is afloat and the falls are slack. On-load release opens them with weight on the hooks, for a ship that cannot wait, for example when making way. On-load release is protected by a hydrostatic interlock and a breakable cover so that nobody can trigger it by accident.

Can I lower a lifeboat faster to save time in a drill?

No. The maximum lowering speed is a design limit that protects the people inside and the structure during a sudden stop. The appliance must have means to keep the speed under it.

Check yourself

6 questions. Pass with 60% to mark the lesson as done.

  1. 1 A fall wire looks clean and bright on the drum. Where is the corrosion most likely hiding?
  2. 2 The winch brake lever has been tied in the “off” position with a lashing to make lowering easier. What is wrong?
  3. 3 Which safety factor applies to the falls?
  4. 4 Why must a fully reset hook transmit no force from the boat’s weight to the operating mechanism?
  5. 5 What protects the on-load release from accidental use?
  6. 6 A davit is in good condition but the lifeboat now weighs more than its recorded weight. Why does that matter?

Sources

  1. 1 IMO Resolution MSC.48(66), International Life-Saving Appliance (LSA) Code (adopted 4 June 1996), chapter VI, paragraphs 6.1.1.1, 6.1.1.3, 6.1.1.5, 6.1.1.6, 6.1.2.2, 6.1.2.3, 6.1.2.5 to 6.1.2.12. https://wwwcdn.imo.org/localresources/en/KnowledgeCentre/IndexofIMOResolutions/MSCResolutions/MSC.48(66).pdf
  2. 2 IMO Resolution MSC.216(82), Amendments to SOLAS 1974 (adopted 8 December 2006, in force 1 July 2008), Annex, item 25: new text of regulation III/20.4. https://wwwcdn.imo.org/localresources/en/KnowledgeCentre/IndexofIMOResolutions/MSCResolutions/MSC.216(82).pdf
  3. 3 IMO Resolution MSC.320(89), Amendments to the LSA Code (adopted 20 May 2011, in force 1 January 2013), Annex, paragraph 4.4.7.6. https://wwwcdn.imo.org/localresources/en/KnowledgeCentre/IndexofIMOResolutions/MSCResolutions/MSC.320(89).pdf
  4. 4 IMO Resolution MSC.48(66), LSA Code, chapter IV, paragraphs 4.4.6.1, 4.4.6.3, 4.4.6.5, 4.4.6.8, 4.8 and 4.9.1. https://wwwcdn.imo.org/localresources/en/KnowledgeCentre/IndexofIMOResolutions/MSCResolutions/MSC.48(66).pdf
  5. 5 IMO Resolution MSC.218(82), Amendments to the LSA Code (adopted 8 December 2006, in force 1 July 2008), Annex, items 30 and 31 (paragraphs 6.1.2.12 and 6.1.2.13). https://wwwcdn.imo.org/localresources/en/KnowledgeCentre/IndexofIMOResolutions/MSCResolutions/MSC.218(82).pdf
  6. 6 IMO Resolution MSC.554(108), Amendments to the LSA Code (adopted 23 May 2024, in force 1 January 2026, for appliances installed on or after 1 January 2026), Annex, paragraphs 4.4.7.6.8, 6.1.2.8 and 6.1.2.10. https://wwwcdn.imo.org/localresources/en/KnowledgeCentre/IndexofIMOResolutions/MSCResolutions/MSC.554(108).pdf
  7. 7 IMO Resolution MSC.47(66), Amendments to SOLAS 1974 (adopted 4 June 1996), regulation III/31.1. https://wwwcdn.imo.org/localresources/en/KnowledgeCentre/IndexofIMOResolutions/MSCResolutions/MSC.47(66).pdf
  8. 8 The Bahamas Maritime Authority, Marine Notice 82, Lifeboat Safety, version 1.1 (effective 1 November 2023), sections 10.2 and 10.3. https://www.bahamasmaritime.com/wp-content/uploads/2023/10/MN082-Lifeboat-Safety.pdf
  9. 9 Liberia Maritime Authority, Marine Notice SAF-005 (Rev. 07/26), section 5 (maintenance of falls). https://www.liscr.com/sites/default/files/online_library/SAF-005.pdf
  10. 10 IMO Resolution A.1207(34), Survey Guidelines under the HSSC, 2025, Annex, paragraphs (EA) 1.2.2.20 and 1.2.2.23. https://wwwcdn.imo.org/localresources/en/OurWork/IIIS/Documents/A%2034-Res.1207%20-%20SURVEY%20GUIDELINES%20UNDER%20THE%20HARMONIZED%20SYSTEMOF%20SURVEY%20AND%20CERTIFICATION%20(HSSC),%202025%20(Secretariat).pdf
  11. 11 IMO Resolution A.1185(33), Procedures for port State control, 2023 (adopted 6 December 2023), Appendix 6, section 5 (life-saving appliances). https://wwwcdn.imo.org/localresources/en/KnowledgeCentre/IndexofIMOResolutions/AssemblyDocuments/A.1185(33).pdf
  12. 12 Transport Malta Marine Safety Investigation Unit, Safety investigation report 05/2014, Thomson Majesty, lifeboat wire fall failure on 10 February 2013, as reported by Cruise Industry News, May 2014. https://cruiseindustrynews.com/cruise-news/2014/05/investigation-of-lifeboat-drop-faults-corroded-rope-wire/
  13. 13 UK Marine Accident Investigation Branch, Safety Study 1/2001, Review of lifeboat and launching systems’ accidents, section 1.4. https://assets.publishing.service.gov.uk/media/5a7d8042ed915d2d2ac0954a/Lifeboat_Study.pdf
  14. 14 Tokyo MOU, Annual Report on Port State Control in the Asia-Pacific Region 2025, figure 8 and table 15. https://www.tokyo-mou.org/wp/wp-content/uploads/ANN25.pdf

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