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

🕑 5 min read words Safety • Incident

Vessel: Finnmaster, 154.5m ro-ro cargo ship
Date & location: 19 September 2021, King George Dock, Hull
Outcome: Auxiliary engine room fire, total power loss, CO2 system failed to fully extinguish, emergency generator breaker failed to connect. No injuries; vessel re-berthed with tug assistance
Human factors: Normalisation · Complacency · Untested Emergency Systems
Source: MAIB Report 13/2025

9 decision nodes4 outcome paths — escalated fault / silently managed fault~7 min read + Knowledge Checker

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

Draft IMO guidance on the conduct and frequency of on-load emergency power testing (MAIB 2025/135)
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)
Provide fleet-wide guidance for identifying and escalating recurring machinery fault trends (2025/140)
Update ship familiarisation and training to cover all equipment critical to emergency response, with realistic power-loss drills (2025/141)

Human Element Analysis

Normalisation

Coupling slippage had become a fault the crew simply managed locally, trip after trip, rather than a warning sign requiring escalation to the manufacturer.

Complacency

A CO2 service certificate and a generator start-test were both accepted as proof of readiness without anyone independently verifying the full chain of function — connection under load, gas delivery to the seat of a fire.

Untested Emergency Systems

Drills had never rehearsed the exact combination that occurred — simultaneous power loss, communication failure, and darkness — leaving the crew's real response to fall short of the accepted CO2 activation procedure under pressure.

How This Pattern Repeats

Industry	Incident	The parallel
Nuclear	Fukushima Daiichi, 2011	Emergency backup power systems assumed functional after routine testing that never simulated the actual failure combination that later occurred.
Oil & Gas	Piper Alpha, 1988	An unapproved or unescalated equipment modification creating a hidden hazard that survived years of routine survey undetected.
Aviation	British Airways Flight 5390, 1990	An unapproved component substitution (windscreen bolts; here, an unapproved fuel hose) that passed unnoticed through maintenance sign-off until it failed catastrophically.

See How You'd Handle It

The scenario opens with a coupling slippage fault you've seen before, quietly managed again this trip. What you do with that pattern is the first decision point.

What Every Chief Engineer Should Take From This

A recurring fault, however minor each time, is a trend — escalate it to the company and OEM, not just the maintenance log
Never accept an unapproved modification near hot exhaust components without classification society sign-off
A CO2 service certificate is not proof the system will actually deliver gas — verify independently where possible
Emergency generator testing must prove connection to the switchboard under load, not just that the set starts
Drill for the compound failure — power loss, comms loss, darkness — together, not each in isolation

Test Your Knowledge

Think you've got this covered? Put it to the test in Crew Connect's free Knowledge Checker — try a quick engineering round and see how you score. Or try the full branching Decision Simulator scenario built from this investigation — work through the real decision points and see which ending you reach.