Across the marine sector, tugboats are relied on to deliver immediate, controlled power, often in very demanding conditions.
And a recent survey on a working tug highlighted just how serious and severe an overspeed event can be.
The Bartech team were invited to attend in Ramsgate to assess a Deutz 8M528 main engine following a reported failure.
On arrival, the situation was already well advanced, the engine had oversped, seized, and been partially stripped by the vessel crew.
The root of the issue began with a turbocharger failure, which led to the engine running beyond its safe operating limits.
Overspeed events of this nature are particularly damaging. Within seconds, critical components can be subjected to forces far beyond their design limits.
On inspection, the engine had been reduced to a block and crankshaft assembly, but the condition of the remaining components pointed out some of the issues:
• Crankshaft journals exposed to sea air corrosion
• Extensive rusting across big end and main journals
• Surface damage likely requiring grinding and polishing
• Potential requirement for oversize bearings
Even the engine block showed early signs of corrosion, although some areas may still be recoverable.
Once internal components are exposed to marine conditions, deterioration begins immediately. Corrosion can quickly turn a repairable component into one that requires full replacement.
Given the extent of the damage, a full in-situ repair was not viable.
The only practical solution:
• Remove the engine from the vessel
• Transport to Bartech’s Colchester facility
• Carry out full inspection, machining and rebuild under controlled conditions
This in itself presents logistical challenges – the vessel will need to be moved to a location with suitable crane access or dry dock, and structural obstructions, including deck fittings above the engine hatch, will need to be removed to allow safe extraction.
This case highlights a few key points:
• Overspeed events rarely cause isolated damage – they affect the entire engine
• Time is critical once components are exposed to air, especially in marine environments
• Controlled workshop overhaul is often the only reliable route to full recovery
• Early decisions can significantly impact overall repair cost and outcome
The next step is to progress with engine removal, full overhaul and reinstallation, returning the vessel to reliable service.
The Bartech team excel at all the above, but this story highlights again the value in regular checks and services, to reduce downtime and costly repair and overhaul work.
If there are warning signs, they’re there for a reason.
