Underwater rigging failure
- Safety Flash
- Published on 1 January 1999
- Generated on 11 April 2026
- IMCA SF 01/99
- 1 minute read
During the recovery of two 400kg buoyancy blocks from the seabed a swaged eye of a strop failed and one of the blocks rose uncontrolled to the surface. No one was hurt and there was no damage.
What were the causes?
Our Member’s investigation revealed that the eyes of the strop were made up in the usual way, i.e. with an alloy swaged sleeve. It had been under water for about 11 months, during which time the sleeve corroded, causing the eye and wire to fail.
Recommendation
The contractor involved has suggested the following precautions should be taken:
- Do not plan to use alloy swaged rigging which may be left under water for long periods.
- Use extra caution when recovering subsea loads which may have alloy swaged eyes fitted. Check to find out how long the rigging has been submerged.
- Inspect alloy swaged eyes for pitting and other signs of corrosion before use – discard them if there is any doubt about their condition.
- Visually inspect rigging each time it is used.
- Inspect alloy swaged eyes for pitting and other signs of corrosion before use – discard them if there is any doubt about their condition.
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.