ROV main lift failure
- Safety Flash
- Published on 9 December 2021
- Generated on 23 June 2025
- IMCA SF 34/21
- 2 minute read
A termination failed during launch of an ROV for a test dive, and the ROV/TMS assembly fell to the seabed. No-one was harmed. The umbilical termination slipped through the wirelock socketing.
What happened?
It was noted that the umbilical termination had been done only a few days beforehand and been load tested to 1.5 x the weight of the ROV/TMS assembly.
What was the cause?
Third-party investigation concluded that the four main causes of the failure were:
- The volume of the bullet/cone was too small giving too narrow a passage for the wirelock to flow and fill the bullet.
- Uneven distribution of strains, with the majority close to the outside perimeter of the cone.
- Too high force applied during docking.
- Excessive resin in the broad end of the cone changed the intended shape of it, thereby decreasing the cone’s function.
Corrective action / lessons learned
- The root cause was sub-optimal cleaning and strand distribution within too small a cone, which was difficult to work with. The cone was changed to a bigger one.
- Adjustment of docking head dampers.
Members may wish to refer to:
- IMCA R004 – Guidance for the safe and efficient operation of remotely operated vehicles
- IMCA LR011, R011 – The initial and periodic examination, testing and certification of ROV launch and recovery systems
Related Safety Flashes
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IMCA SF 27/19
22 November 2019
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IMCA SF 29/18
21 December 2018
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IMCA SF 06/13
3 May 2013
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