Marine Accident Investigation Branch
Safety bulletin 1/2023
Summary
On 19 September 2021, a fire broke out in the auxiliary engine room on board the Finland registered roll-on/roll-off cargo ship Finnmaster while departing Hull. The fuel source for the fire was identified as coming from a small-bore flexible hose that failed due to being overheated by an exhaust gas leak from the outboard turbocharger of auxiliary engine 2.
The flexible hose assembly was part of a modification made to the auxiliary engine alarm system more than 15 years prior to the fire. It was contrary to requirements and relevant guidance, as it was too long and had been routed close to hot surfaces. The hose had not been approved or surveyed by the classification society when it was installed. Furthermore, despite being replaced a number of times in the intervening period, the material, length and routing of the hose had remained the same throughout and the risk it posed had not been identified or mitigated.
Safety issues
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The risks associated with a modification on safety critical equipment should be considered before and during the work being completed. The relocation of the pressure switch closer to the cartridge filters would have removed the need for a long hose; if this was not possible, a rigid metal pipe secured with clamps and routed at an appropriate distance from the engines exhaust might have been a safer option.
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Flexible hoses are recognised as having a higher risk of failure than a properly fitted metal pipe. An isolation valve fitted at the point of supply allows a flexible hose to be safely isolated in the event of leakage.
This accident remains under investigation and the detailed causes and circumstances will be published in an investigation report in due course.
Related publications
In March 2022, Safety Bulletin 1/2022 was issued, relating to the same accident but highlighting serious concerns about potential defects in CO2 fixed fire-fighting systems.