Definition
The emergency release mechanism on a towing hook fails under load, preventing the crew from freeing the tug from the towline. This is an equipment failure that typically contributes to or causes a capsize girding incident.
Why it matters
In a girding situation, the crew's last option to save the tug is releasing the towhook. If the release fails:
- The tug cannot free itself from the towline load
- Capsize becomes almost certain
- Crew cannot escape
Towhook failure turns a survivable girding situation into a fatal one.
Failure modes
- Mechanical seizure under load (release requires force the crew cannot apply)
- Hydraulic release system failure
- Electric release system failure
- Release mechanism not designed for load conditions encountered
- Crew unable to reach the release in time
Related incidents
Accidents linked to this concept are grouped by vessel type.