The team at Gard P&I Club has issued recommendations to help ship operators prevent blackouts and ensure that crews are prepared to respond effectively should one occur.
A blackout occurs when a ship suffers loss of electrical power from its main switchboard, typically due to an electrical or mechanical failure in the ship’s power generation, distribution, or propulsion systems. All blackout situations are serious and potentially dangerous. In a best-case scenario, a standby generator will be brought online to restore the main source of electrical power within seconds. However, a sustained blackout with loss of propulsion and steering control can eventually lead to collision or grounding with loss of life, damage to the environment and even total loss of the vessel.
The risk of a serious casualty increases when a ship is operating close to shore, near other ships or infrastructure like offshore wind turbines and particularly under adverse weather conditions. The increasing complexity of the integration of operating systems on modern ships has also been shown to challenge crews’ capacity to understand how these systems work. This can have a significant impact on how long it takes to recover from a blackout and restore propulsion and steering, and hence the severity of a blackout.
Key recommendations against blackouts
To prevent blackouts from occurring, ship operators must ensure that all essential machinery, electrical equipment and control systems are correctly maintained and operated. According to DNV, some of the typical failures to be aware of are:
– Loss of lube oil pressure
– Fuel-oil related issues, e.g. clogged filters
– Control, monitoring and safety system malfunctions
– Common maintenance failures. This could happen when similar maintenance is carried out on several auxiliary engines at the same time
Gard also recommends carrying out regular and realistic performance testing of auxiliary and emergency power supply systems as well as surveying switchboards with an infrared camera. Even systems with redundant power supply might fail at the worst possible time if not properly maintained.
To reduce the effects of a blackout, ship operators should develop robust operating procedures that identify ship-specific operations where a blackout could represent a particularly high risk, e.g. during berthing or navigation in heavy weather, different system failures that could occur, and how to best respond if a failure occurs. Special attention should be made to the configuration of main and auxiliary switchboards to provide redundancy in power supply for propulsion and supporting systems.
Additionally, Gard emphasises to ship operators the importance of having an alarm system that is clear and unambiguous. Every blackout will activate a large number of alarms, and it is essential that the engineers on watch can quickly recognise those that are critical. As an example, the investigation (report in Norwegian) of the above mentioned cruise ship accident revealed that the ship’s alarm system in the engine control room failed to distinguish between critical and less critical alarms, and that “troubleshooting was challenging when a total of approximately 1,000 alarms sounded within the first 10 seconds after the blackout”.
Onboard drills to test system responses triggered by different, and realistic, blackout failures should be conducted on a regular basis to improve crew awareness. The Failure Modes and Effect Analysis (FMEA) of the complete power management system would be a good resource for operations and training of crew. When used as a reference document, it can improve operator understanding of the risks and corrective actions the automation system performs should a particular failure occur. Remember, your best strategy to avoid accidents is to make sure every ship has a skilled and confident crew, who understand how to prevent and respond to a blackout in order to recover as quickly as possible.