Entry & progression
The engine room is the most dangerous compartment on the vessel. This is not a paperwork lesson. Every hazard on this list has killed working engineers, and most of them kill quickly.
Enclosed spaces
Tanks, cofferdams, void spaces, chain lockers, sealed bilges. They kill by oxygen deficiency — invisibly, in seconds, with no warning sensation. And they kill in twos and threes, because the rescuer goes in after his shipmate.
WARNING — Never enter an enclosed space without a permit and a test No permit, no atmosphere test, no attendant at the opening, no means of rescue — no entry. Not for thirty seconds. Not to grab a spanner. And if a man goes down inside one, do not follow him in. Raise the alarm, get the rescue equipment and breathing apparatus. The great majority of enclosed-space deaths at sea are would-be rescuers, and everybody who died that way was brave.
Fire
The classic engine room fire is oil under pressure meeting a hot surface — a cracked fuel line, a weeping injector pipe, a hydraulic hose spraying onto an unlagged exhaust. Which is why the discipline is boring and absolute: lagging stays on, oil leaks get fixed, not wiped, and rags do not live on hot surfaces.
Know, before you need it, where the fixed extinguishing system releases, where the emergency stops and quick-closing fuel valves are, how the space is shut down and sealed, and where the muster is. Know it in the dark, because that is when you will need it.
Electrical
Isolate. Prove dead. Lock out and tag. Then work. There is no version of this that is safe to shorten because the boat is busy. And on high-voltage systems, the rule is harder: no contact is needed for an HV system to kill you, and nobody touches HV without the specific training and the switching procedure.
The rest of the list
| Hazard | The rule |
|---|---|
| Rotating machinery | Guards on. No loose clothing, no gloves near rotation, nothing dangling. |
| Steam and hot fluids | Scalding is invisible in the air. Treat every line as live until proven dead. |
| Pressure | Depressurise and drain before you crack a fitting. Stored energy has no warning. |
| Refrigerant / CO2 | Displaces oxygen in a low space. Ventilate; never work alone in a gas room. |
| Noise | Hearing loss is total, permanent and painless. Wear the defenders every time. |
| Crankcase explosion | Hot bearing, oil mist. Do NOT open a crankcase on a hot engine — let it cool. |
Permits, lock-out, and the word no
Every rule above reduces to two behaviours. Lock out and tag out — isolate the energy, lock the isolation, hang the tag, and keep the key on your person. And stop the job when something has changed and the plan no longer fits it. A rating who stops an unsafe job is doing precisely what the support level exists to do: he has seen the thing that the man who wrote the plan could not see from where he was standing.
NOTE — The Coast Guard takes engineering firefighting seriously — and so should you 46 CFR 11.201(h)(2)(iv) requires Basic AND Advanced Firefighting for all national officer endorsements for engineers — every grade, including the lowest. Deck licences below 500 GT ocean need only basic firefighting. The engineering entry bar is deliberately higher than the deck one. That is a regulator telling you, in the only language it has, where it expects the fire to start.