Offshore crane boom hoist rope failures

Health and Safety Executive - Safety notice

Department name: ED - Energy division

Bulletin number: ED01 - 2022

Issue date: 01/22

Target audience: All personnel involved in the operation, maintenance, and inspection of offshore cranes.

Issue: Two incidents have occurred offshore, involving the failure of crane boom hoist ropes, resulting in the crane booms falling onto the deck below.

Duty holders are advised to ensure that:

  • when high winds are forecast, the positioning, and if necessary, the securing of crane booms, is in accordance with the relevant crane manufacturer’s guidance
  • if manufacture’s guidance outlines that the boom should be stowed in the boom rest, slack rope should not be allowed to form between the sheaves in the ‘A’ frame and those at the boom tip or bridle assemblies
  • cranes are operated in a controlled and smooth manner to reduce, so far as is possible, any bouncing of the crane boom
  • when a crane is designed to have sheave rope retention bars fitted, these are in a good condition
  • crane pre-use checks include the requirement to verify that all the ropes are correctly seated and running in the rope sheaves
  • when new boom hoist ropes are fitted that the method of installation reduces the possibility of a twist being introduced into the new rope

During 2020, two separate incidents occurred on offshore installations as a result of the failure of a crane boom hoist rope. In both incidents the boom hoist rope came off a sheave; this was undetected and the consequential severe damage to the ropes ultimately resulted in their catastrophic failure.

Although no person was injured in either incident, the falling crane booms (together with the loads being lifted at the time), resulted in structural damage to the crane booms. Both incidents had the potential to cause death or serious injury to the persons involved in the lifting operations and to other persons on the Installations.


On one crane the rope came off a sheave in the 'A' frame and then dropped down onto an adjacent sheave bearing housing. This caused considerable wear and damage to the bearing housing.

On the other crane, the rope climbed out of a sheave in the boom tip and dropped down into the gap between this sheave and boom tip side plate. This also resulted in the rope being forced up against a structural member in the boom tip structure. The rope then cut a groove almost fully through this structural member.

Failure during lifting

Consequently, both boom hoist ropes suffered such serious damage that they eventually failed whilst the cranes were undertaking lifting operations.

In the case of both incidents, the said ropes may have come off a sheave due to one of the following reasons:

Action required

To prevent an incident of this nature, relevant offshore installation duty holders and contractors involved in the operation, maintenance and inspection of offshore cranes, must where appropriate and so far as is reasonably practicable, ensure that:

Relevant legal documents


Further information

Health and Safety Executive
Redgrave Court
Merton Road
L20 7HS