Wire inserts in anchor line parted
- Safety Flash
- Published on 14 August 2007
- Generated on 16 May 2026
- IMCA SF 07/07
- 2 minute read
A Member has reported an incident in which wire inserts parted in two anchor lines of a semi-submersible accommodation unit connected to a fixed platform during extreme weather conditions (9m seas, 70knot winds).
What happened?
Non-essential personnel were taken off the semi-submersible accommodation unit until the mooring system could be safely recovered and replaced.
During recovery of the mooring system it was discovered that the wire inserts in both the affected mooring lines had slipped out of the socket at the rig end. The wire inserts were taken ashore for investigation.
What were the causes?
Following investigation, the following was noted:
- The failed wire inserts had not been moulded on to the sockets using proper procedures.
- The supplier of the failed wire inserts was not aware of the procedure and its personnel were not formally trained in the moulding operation.
- The supplier of the wire inserts and other contract-specific anchoring equipment had not been audited by this or any other customer.
- Similar incidents regarding wires slipping out of sockets had occurred but had not been brought to public attention.
- There was a detailed investigation of the design of the mooring system. The system used mooring lines supported by buoys, but it was not possible to ascertain that this was directly causative.
Lessons learnt
The company recommended the following:
- higher awareness of procedures for moulding sockets on to wires and increased training for personnel engaged in such work to ensure that personnel involved are properly qualified for the work.
- audit of suppliers of contract specific mooring equipment for appropriate quality management system.
- free sharing of similar incidents to prevent recurrence of incident.
- research into testing wires with moulded sockets.
IMCA Safety Flashes summarise key safety matters and incidents, allowing lessons to be more easily learnt for the benefit of the entire offshore industry.
The effectiveness of the IMCA Safety Flash system depends on the industry sharing information and so avoiding repeat incidents. Incidents are classified according to IOGP's Life Saving Rules.
All information is anonymised or sanitised, as appropriate, and warnings for graphic content included where possible.
IMCA makes every effort to ensure both the accuracy and reliability of the information shared, but is not be liable for any guidance and/or recommendation and/or statement herein contained.
The information contained in this document does not fulfil or replace any individual's or Member's legal, regulatory or other duties or obligations in respect of their operations. Individuals and Members remain solely responsible for the safe, lawful and proper conduct of their operations.
Share your safety incidents with IMCA online. Sign-up to receive Safety Flashes straight to your email.