Reefer Container Temperature Excursion
A 4,500 TEU container vessel is on passage with 180 reefer containers. The cargo includes a block of 40 frozen-food reefers set to −18 °C and a group of 20 chilled produce reefers set to +4 °C. At 0600 the watchkeeper reports that the aft reefer bay has lost power. The vessel's reefer monitoring system shows 12 containers in that bay with rising temperatures; the frozen units are at −12 °C and the chilled units at +9 °C. The vessel is 36 hours from the next port. The chief engineer reports that the bay's circuit breaker tripped and that the backup generator is available but the bay's distribution panel shows signs of water ingress. The charterer's instructions require notification of any temperature deviation above 2 °C.
1. Prioritise the actions to protect the cargo and the vessel, explaining the reasoning behind the order.
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Priority order:
- Safety of the vessel and crew. Water ingress in an electrical distribution panel is a fire and shock risk. Isolate the panel, post warnings, and have the chief engineer assess before re-energising. Do not restore power to a wet panel.
- Protect the cargo. Once the panel is safe, restore power from the backup generator to the reefer bay as soon as possible. Frozen cargo at −12 °C is outside its setpoint but has thermal inertia; chilled produce at +9 °C is more time-critical because chilling injury and decay accelerate above about +4 °C.
- Notify. Inform the charterer and cargo interests of the deviation, as required, with times and temperatures. This preserves the vessel's position and allows the charterer to instruct.
- Record. Log all readings, actions, and times for later cargo claims.
- Monitor. Increase inspection frequency in the affected bay and check adjacent bays for similar faults.
The reasoning is that the chilled cargo has the shorter tolerance and the electrical fault is a vessel safety issue that must be controlled before power is restored.
2. Explain how you would decide whether to divert or continue, and what records you would keep.
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Diverting 36 hours early would cost time and fuel and may not be necessary if power can be restored within a few hours. I would decide on the basis of:
- Time to restore power versus the thermal tolerance of each cargo. Frozen food at −12 °C can generally tolerate several hours if the doors remain closed and the ambient is low; chilled produce at +9 °C has a much shorter tolerance.
- Whether the cargo can be saved by restoration rather than by diversion. If the panel can be repaired and power restored within, say, 4–6 hours, continuing is reasonable.
- The charterer's instructions and the terms of the carriage contract, which may specify a notification and mitigation duty.
- Port options - whether a closer port with reefer facilities exists.
Records to keep: the initial and subsequent temperature readings with times, the fault report, the repair log, the notification to the charterer, the master's decision and reasons, and any instructions received. These records support the vessel's defence that it acted reasonably to mitigate loss.