Non-genuine parts and shortfall in oversight led to fire on offshore vessel

At 1305 on 25 January 2025, the DP2 multipurpose site investigation vessel Kommandor Susan suffered what the MAIB described as a catastrophic failure of a diesel generator while conducting sea trials in the Firth of Forth, Scotland. The failure resulted in an engineroom fire and a complete power blackout. 

The crew responded promptly, extinguishing the fire and mustering safely, but 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.

Kommandor Susan was built in 1999 as an offshore supply vessel. In 2018, the vessel was sold to Hays Ships Limited and in 2022, Kommandor Susan was sold to Gardline Shipping Limited.

An investigation by the MAIB found that the generator failed because of the use of non-genuine engine components during a major overhaul in 2019. Subsequently, extended service intervals were approved, which assumed use of genuine component. There was also a shortfall in oversight and contractor assurance by the vessel owner during overhaul, which allowed the non-genuine components to be installed.

The investigation found that the engine failure was caused by premature wear of bearings fitted during the overhaul. These components were not approved by the engine original equipment manufacturer and exhibited weaker material bonding than genuine parts. The extended service intervals applied to the engines were valid only for original equipment manufacturer components, making the use of substitute parts a critical factor in the failure.

The MAIB said the vessel’s former owner had minimal oversight of the overhaul process and assumed that original equipment manufacturer parts were used. This lack of verification meant that the presence of substitute components remained undiscovered and was not communicated to subsequent owners. Additionally, the vessel’s anchoring procedure did not account for the risk of power loss, leaving the anchors inoperable during the emergency.

The vessel’s owner, Gardline Shipping Limited, has since rebuilt the affected engine, and overhauled all other generator engines on board Kommandor Susan, with original equipment manufacturer parts.

No recommendations were made as a result of this investigation, but the chief inspector of marine accidents has written to the vessel’s previous owner, Hays Ships Limited, outlining the importance of a structured supervision system that provides clear accountability measures and the need to adopt monitoring for all critical maintenance activities.