The Fire the CO2 System Couldn't Reach: What Finnmaster's Engine Room Fire Teaches Every Chief Engineer About Modifications, Servicing, and Blind Trust

King George Dock, Hull — 19 September 2021

As Finnmaster manoeuvred stern-first out of dock at 2013, fire detection alarmed in the auxiliary engine room. The first engineer found exhaust temperatures on AE2 exceeding 650°C, and a fire ignited below the outboard turbocharger. Engineers were driven back by heat before they could fight it with portable extinguishers. At 2017 the vessel lost all main electrical power and propulsion while drifting in the dock. The emergency diesel generator started automatically — but its circuit breaker failed to connect it to the emergency switchboard, leaving the vessel entirely dark. The fixed CO2 system was activated but a defective flexible hose in the pilot circuit meant insufficient gas reached the fire. Two tugs made the vessel fast and brought her back alongside; the fire team entered in breathing apparatus and finished the job with dry powder extinguishers.

The Fault Line Nobody Reported

Historic coupling slippage faults on AE2's fuel injection pump had been logged and locally managed for years, but never escalated to the company or the engine manufacturer. An unapproved modification to the AE alarm/monitoring system had exposed a non-standard flexible fuel hose to elevated exhaust temperatures — a hose that had never been submitted to the classification society for approval, and that no survey had caught in the years since. When the coupling partially failed, hot exhaust gas heated that hose until it ruptured, spraying pressurised fuel onto hot components. Meanwhile the CO2 system's March 2021 service had likely not followed the manufacturer's procedure and missed the defective pilot hose entirely — a certificate of service was accepted without independent verification that the system actually worked. The emergency generator's circuit breaker had a latent defect that routine testing had never caught, because the test regime only confirmed the generator started, not that it could connect to the switchboard under load.

Recommended Actions

1. Draft IMO guidance on the conduct and frequency of on-load emergency power testing (MAIB 2025/135)
2. Verify, on completion of any CO2 system service, that the fixed system is fully operational — a certificate alone is not proof of function (2025/137)
3. Provide fleet-wide guidance for identifying and escalating recurring machinery fault trends (2025/140)
4. Update ship familiarisation and training to cover all equipment critical to emergency response, with realistic power-loss drills (2025/141)