The best captains have always been the most vigilant ones. In the age of sail that meant being ever alert to threats from other vessels, changes in the weather and sea conditions, underwater hazards, and yes, recalcitrant crew. But with the advent of steam and finally petroleum power, the master also had to focus on internal threats. It soon became obvious that the most dangerous place on the ship was the engine room.
That’s still true. If something bad happens on your vessel, chances are it will be where there are hot, rapidly moving objects and flammable substances on hand. The threat of such a mishap never fully disappears, even when you’re tied to the dock. You can only minimize the danger.
Look at engine-room safety from two perspectives: when the ER is occupied and when it’s not. Many of you have no intention of going into your engine room while underway, but go to sea long enough and you will, whether it’s to investigate an alarm or because you sense something’s wrong. That’s why it’s common sense to be prepared to enter a “live” engine room, and that means protecting yourself.
Rule number one is to wear ear protection. Don’t rely on earplugs (or wadded up tissue paper); buy a good pair of acoustical earmuffs and designate a place near the entrance where they will hang. I’ve had a pair of 3M earmuffs for years—they work great and cost about $15. I also own a pair of tight-fitting work gloves because most everything in a live engine room is hot enough to burn you. If I need to work with something small, I just take them off. For further protection from burns I usually wear a sweatshirt, even though the engine room temperature argues against it. It hangs by the door with the muffs. If you decided to do likewise just make sure it fits snugly.
When you enter an engine room the engines should be at idle, but while the propshafts may not be turning, other things will be. A main cause of injury in an engine room is coming into contact with moving parts. You can minimize the chance of a mishap by avoiding loose-fitting clothing and accessories—yes, accessories. I once watched in horror as the gold chain a colleague was wearing around his neck snagged a shaft coupling and nearly strangled him. Thankfully it snapped just as his tan was turning to puce, and he survived unharmed.

Next, there’s lighting. If you can’t see a potential hazard you’ll have trouble avoiding it. My experience is that newer boats have pretty good overhead lighting while many older boats do not. But engine rooms are notorious for having shadowed nooks and crannies where you can’t see anything. Overhead lighting will only take you so far; you need to supplement it with a portable lamp—at the very least a high-intensity flashlight that throws a powerful, tightly focused beam. I have a CV Life 1800 rechargeable with a focusable lens, which I kept in my engine room, wired to the boat’s electrical system so it was always fully charged.
Unfortunately engine-room mishaps often occur when the space is unoccupied, and often the culprit is the improper handling and/or stowage of flammable materials. There are certain things that should never be in an engine room, among them spare lube oil, all solvents, and all rags—even clean ones. Engine rooms contain petroleum-based fumes that rags can absorb. If they absorb enough of it, spontaneous combustion and fire can result. Rags belong in either your lazarette or in a dockbox, and should always be stored in a tightly sealed container.
Then there are batteries. When I worked as a mechanic, I was always surprised at how often I found them improperly installed—insecure mounting, no dedicated containers (i.e., battery boxes), and inadequate ventilation. All batteries require ventilation, preferably to the outside. Another common failing: Missing or misplaced positive-pole protection—you know, that annoying red plastic cap? It’s there for a reason: to prevent arcing across the battery poles. It only takes a dropped tool, and sparks are not something you want in your engine room.
Finally there are oil leaks. Hot oil is particularly combustible so if your engine’s a dripper, place an absorbent mat under the leak and change it often. Even a smidge of oil is problematic and should be wiped up immediately. Oil and fuel leaks are a primary cause of fires, which means you need to frequently check the condition of all hoses and fittings, especially if you have an older engine. Rubber does not last forever, so replace aged hoses before they fail.
Engine-room fires and other related mishaps are rare but by no means inconceivable. So while you’re keeping that sharp eye out for pirates and hurricanes, don’t forget also to check on your engine room.