Sea trials in the Firth of Forth, Scotland that ended in catastrophic engine failure and a fire on board a vessel last year was caused by substitute components said a report by the Marine Accident Investigation Branch (MAIB).
What happened
At 1305 on 25 January 2025, the site investigation vessel Kommandor Susan suffered a catastrophic failure of a diesel generator engine while conducting sea trials in the Firth of Forth, Scotland. The failure resulted in an engine room fire and a complete power blackout. The crew responded promptly, extinguishing the fire and mustering safely. The vessel lost propulsion and began drifting eastwards. Attempts to deploy anchors were unsuccessful because the anchor winches required electrical power to operate. Kommandor Susan was eventually returned to Leith harbour with limited propulsion restored.
Safety issues
- use of non-genuine engine components during a major overhaul in 2019
- approval of extended service intervals, which assumed use of genuine components
- a shortfall in oversight and contractor assurance by the vessel owner during overhaul, which allowed the non-genuine components to be installed.
Recommendations
In view of the actions already taken (see below), no recommendations have been made.
MAIB actions
The Chief Inspector of Marine Accidents has written to Hays Ships Limited, outlining the importance of robust oversight during critical maintenance activities and the need to adopt a system of structured supervision, ensuring clear accountability and real-time progress monitoring.
Gardline Shipping Limited has:
- Rebuilt DG1 with genuine spares, including a new engine block;
- Completed major overhauls of DG2, DG3 and DG4 using genuine Caterpillar parts;
- Changed the onboard anchoring procedure, highlighting that clutches must remain disengaged when the winches are not in use to ensure they remain ready for use in the event of power failure.
Download the report: MAIB 10-2026 - Kommandor Susan