The diesel generator engine failure that sparked an engine room fire and total power blackout on board the UK-flagged site investigation vessel Kommandor Susan in January 2025 was caused by substitute engine components installed during a 2019 overhaul, the investigation report issued by the UK government organization Marine Accident Investigation Branch (MAIB) states.
Owned by Gardline Shipping Limited, Kommandor Susan suffered the failure of a diesel generator engine at 1:05 p.m. on January 25, 2025, while performing sea trials in the Firth of Forth, Scotland.
Due to a complete power blackout, the vessel lost propulsion and began drifting eastwards, while attempts to deploy anchors failed because the anchor winches required electrical power to operate. Limited propulsion was then restored, allowing the vessel to return to Leith Harbour.
There were 14 people on board at the time of the incident, with no reported injuries or fatalities.
The investigation found that the engine failure was caused by premature wear of bearings fitted during a major overhaul in 2019. These components were not approved by the engine original equipment manufacturer (OEM) and exhibited weaker material bonding than genuine parts. The extended service intervals applied to the engines were valid only for OEM components, making the use of substitute parts a critical factor in the failure, MAIB’s report writes .
According to MAIB, Hays Ships Limited, the former owner of the vessel, had minimal oversight of the overhaul process and assumed that OEM parts were used, which 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.
Current owner Gardline Shipping has since rebuilt the affected engine and overhauled all other generator engines with OEM parts.
Kommandor Susan was built in 1999 and is 83.7 meters long.