The following case study is from CHIRP Maritime’s Superyacht Feedback. It is the first superyacht-specific programme and publication dedicated to improving safety in the maritime industry through vital knowledge sharing, anonymous reporting, analysis and feedback via the Superyacht Maritime Advisory Board.

Initial report
A relieving master joined a vessel and requested a safety induction, only to discover that no formal induction had previously been carried out. During a full vessel familiarisation covering safety equipment, escape routes, alarms, and emergency procedures, several deficiencies were identified. Firefighting and lifesaving equipment was found to be out of date, incomplete or unserviceable. Once these issues were rectified, the crew completed fire and abandon-ship drills for the first time in several years.

While under engine power approximately 100nm offshore in calm conditions, the master detected the smell of smoke. Other crew members assumed it was related to cooking, but the master investigated immediately. On opening the engine room access, a cloud of atomised diesel fuel was discovered. The engines were shut down, the crew alerted and ventilation increased.

The investigation found that, following previous engine maintenance, an injector vibration mounting had not been refitted. The resulting vibration caused an injector fuel line to fail, spraying diesel fuel onto hot exhaust components and the turbocharger.

The incident had the potential to develop into a serious engine-room fire with limited options for intervention at sea. It reinforces the need to investigate any unusual smell, sound or observation rather than dismissing it, as early reporting and prompt action are fundamental to an effective safety culture.

The event also highlights the importance of verifying maintenance on safety-critical machinery and carrying out regular drills, equipment inspections and familiarisation exercises to identify weaknesses before an emergency occurs.

CHIRP comment
This case shows how several small weaknesses can combine to create a serious fire risk. While each issue may appear minor in isolation, together they weakened the vessel’s safety barriers. Effective maintenance control, crew preparedness and a willingness to act on warning signs must work together as part of one safety system.

The absence of a proper induction and familiarisation process meant that existing deficiencies in firefighting and lifesaving equipment had gone unnoticed. Some equipment was outdated, incomplete or unavailable, and the lack of regular emergency drills reduced the crew’s readiness to respond effectively.

The technical failure resulted from incomplete maintenance. A missing vibration mount on the injector fuel line allowed excessive movement, eventually causing the line to fail. Diesel fuel was then sprayed onto hot exhaust components and the turbocharger, creating the potential for a major engine-room fire. This highlights the importance of effective maintenance completion checks and verification, particularly for safety-critical machinery.

The response to the unusual smell was also significant. Engine rooms develop a familiar background smell from normal operations and experienced seafarers quickly recognise what is normal. Any smell that is different, stronger or out of place should be treated as a warning sign. Fuel, oil, electrical faults, overheating or fire can all present through changes in smell before other indications become obvious. An unusual smell should never be dismissed without investigation.

The master’s actions were critical in preventing escalation. By identifying weaknesses during the initial familiarisation, ensuring equipment deficiencies were corrected, and restarting regular drills, the vessel’s emergency preparedness was improved. During the incident, the prompt decision to stop the machinery, alert the crew, and increase ventilation reduced the likelihood of ignition and further escalation.

The key lesson is that safety depends on maintaining effective barriers at all times. Good maintenance practices, regular training and a culture where everyone feels confident reporting concerns are essential. Small omissions  can develop into major emergencies, but professional curiosity, strong leadership and timely intervention can prevent a serious outcome.

Key issues relating to this report

Factors relating to this incident
Complacency – Demonstrated by the acceptance of degraded safety standards over an extended period. The absence of formal induction, the lack of emergency drills for several years, and the presence of expired or incomplete safety equipment indicate that safety barriers had gradually weakened without effective challenge or correction.

Capability – The technical cause of the incident was traced to incomplete reinstatement following maintenance, where the injector vibration mounting was not refitted. This highlights a weakness in maintenance control, particularly the absence of effective post-maintenance inspection, verification and sign-off processes for safety-critical machinery.

Situational awareness – The crew interpreted the indication as probably related to cooking rather than treating it as a potential engine room hazard. In a high-risk environment, unusual smells, sounds or operating conditions should be recognised as early warning signals that require investigation until they are positively explained.

Communication – There was a lack of communication, as the concern raised by the Master was not initially shared or escalated by other crew members. A strong safety culture requires all personnel to communicate concerns clearly and challenge assumptions, regardless of rank or previous experience.

Distraction – This may be considered as a secondary factor, as the crew were engaged in routine activities when the smoke indication occurred. However, the greater issue was not the activity itself but the failure to prioritise and interpret the warning sign immediately and appropriately.

Key takeaways
Regulators – “Safety barriers are only effective when they are actively verified; an emergency system that has not been tested cannot be assumed to provide protection when needed.” This incident highlights the importance of regulatory oversight focusing not only on the existence of safety management systems but on their effectiveness in practice. The prolonged absence of drills, incomplete safety equipment, and lack of formal familiarisation demonstrate how safety controls can degrade when assurance processes are ineffective.

Managers (Operators / Companies) – “A maintenance task is not complete when the work is finished; it is complete only when the system has been verified safe to return to service.” Managers should ensure that maintenance activities include effective planning, supervision, independent checks where appropriate, and confirmation that equipment has been correctly restored before operation. The missing injector vibration mounting illustrates how a small omission can remove a critical barrier, allowing a technical failure to develop.

Seafarers – “An unusual smell, sound or condition is not a nuisance or inconvenience; it is a safety signal that requires attention until the cause is understood.” Seafarers should recognise that early-warning signs are valuable information that can prevent serious incidents. The initial dismissal of the smoke smell demonstrates how assumptions and familiarity can delay effective response. In high-risk areas such as engine rooms, abnormal indications should always be treated seriously and investigated promptly.

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