How do you recover from a blackout (total loss of electrical power)?

A blackout is the complete loss of main electrical power: the main engine stops, pumps and fans wind down, and the ship is suddenly dark and quiet except for battery-supplied alarms and emergency lights. Recovery is a planned, ordered restart, and the order matters because a wrongly sequenced recovery causes a second blackout on top of the first.

The first response is automatic. The emergency generator must start and connect to the emergency switchboard automatically, within 45 seconds under SOLAS requirements, restoring emergency lighting, steering gear supply, navigation lights and equipment, communications and the emergency fire pump, with transitional battery supplies bridging the gap. The engineer's first actions are to inform the bridge, confirm the emergency generator has picked up, and then resist the urge to simply restart everything: first establish why the plant blacked out. Look at the first-out alarm, the tripped breakers and the state of the generator that was running: a reverse power or overload trip, fuel starvation from a dirty filter or an empty service tank, low lubricating oil pressure, high cooling water temperature, or a short circuit that threw the board. Reconnecting onto an uncleared fault or an empty fuel line simply repeats the blackout.

With the cause identified and cleared, start a main generator and close it onto the dead main switchboard. Then rebuild the load in a controlled sequence so the single machine is not overloaded: cooling water and lubricating oil pumps for the generators and main engine first, then fuel supply and booster pumps, steering (confirmed with the bridge), engine room ventilation, and the auxiliaries needed to restart the main engine, starting and paralleling a second generator as the load grows. Only when the main engine's supporting systems are running is the engine itself restarted, with the bridge informed at every stage. Preferential trips and, on modern ships, the power management system automate much of this sequential restart, but the engineer must know the sequence by hand, because the automation itself can be the casualty.

A blackout in open water is an inconvenience; in a channel or near a berth it is an emergency, with steering and propulsion lost together. The bridge will be preparing anchors and exhibiting not-under-command signals while the engineers work, which is why blackout recovery is practised as a drill, why the emergency generator is tested regularly, and why every engineer should be able to perform a dead-ship start from the emergency generator alone.