Transport Malta issued an investigation report on the fire on a lifeboat while carrying out tests onboard the Maltese-flagged tanker Med Tuncer in May 2020. The investigation identified a very high short circuit current within the batteries as a probable cause of the incident.
The incident
While the oil/chemical tanker Med Tuncer was moored at the Oil Tanking Terminal in Antwerp, Belgium, at 0815 of14 May 2020, the electrician onboard stepped inside the enclosed, freefall lifeboat to carry out tests on the batteries.
During the tests, a fire broke out inside the lifeboat. The fire alarm was raised, and the crew swiftly extinguished the fire. Fire and smoke damage were largely restricted to the interior of the lifeboat and control panel.
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There were no injuries. Although the exact cause of the fire had not been determined, evidence suggested an inadvertent connection of battery terminals in series, resulting in a sudden spike of voltage when the battery selective switch was operated.
Probable causes
The safety investigation could not establish whether main power supply to the lifeboat charging system (which had remained plugged during the battery tests) had contributed to the fire. However, post-accident inspections of the scorched electrical cables suggest an inadvertent connection of battery terminals in series, resulting in sudden spike in circuit current as soon as the battery changeover switch was turned through position marked both to access position 2.
Conclusions
- In all probability, the cause of the fire was a very high short circuit current within the batteries;
- Post-accident inspections revealed that the cables may have not been reconnected as designed;
- The battery changeover switch in the ‘both’ position created a short circuit loop, overheated the wires and welded the switch in mid-position;
- The actual cables had not been marked prior to disconnection and therefore may have been confused during reconnection.
Actions taken
To avoid similar occurrences in the future, the company took the following safety actions:
- Testing of the lifeboat engine will be carried out by two crew members;
- Battery charging cables will be disconnected when not in use and all cable connections checked during every lifeboat inspection;
- An IR thermometer will be used during the testing to monitor the temperature of the cable;
- Testing will be suspended immediately should an increase in temperature be detected;
- An additional portable CO2 fire extinguisher will be kept readily available during the testing of the lifeboat engine;
- A wiring diagram will be posted inside the lifeboat’s battery chest.