Emergency Power: Will It Actually Work in a Blackout?

The Best Case Is Seconds. The Worst Case Is a Collision.

Gard's loss prevention guidance on blackouts starts from an uncomfortable premise: a vessel can have fully redundant power systems and still lose everything at the worst possible moment, if those systems haven't been properly maintained and tested. In the best case, a standby generator comes online and restores main electrical power within seconds. In the worst case, a sustained blackout with loss of propulsion and steering leads directly to a collision or grounding — especially in confined or high-traffic waters.

What Gard Actually Recommends

Two specific, practical recommendations stand out: carry out regular and realistic performance testing of both auxiliary and emergency power supply systems — not just confirming they start, but confirming they perform under load — and survey switchboards with an infrared camera, to catch the kind of developing thermal faults that don't show up on a visual inspection but are a common precursor to electrical failure.

Why “It Passed Its Last Test” Isn't Enough

A generator that starts on a scheduled test, with no load applied and no real demand placed on the switchboard, tells you less than it seems to. The systems that actually matter in a blackout are the ones under real electrical load, in real conditions, restoring propulsion and steering fast enough to matter. Realistic testing means testing under conditions that resemble the emergency you're actually planning for.

What Every Engine Room Should Take From This

• Schedule performance testing that puts real load on standby and emergency generators — not just a start-and-stop confirmation
• Use infrared surveys of switchboards as a routine maintenance tool, not a one-off diagnostic after something has already gone wrong
• Understand your vessel's actual blackout recovery time under realistic conditions, not the manufacturer's best-case specification
• Treat a sustained blackout near land, in traffic, or in confined water as one of the most serious casualties your vessel can experience — the emergency response needs to match that

Related Reading

• The Alarm Is Not the Emergency — how an unverified assumption about a system's state leads to a bigger casualty
• The Plug That's Designed to Fail — another engine room risk that hides until it doesn't