Skip to main content

What Makes a Good Engine Room?

It All Starts in the “Basement.”

Smart engine-room design doesn’t happen by accident. But it’s not as complicated as you may think. These basic principles will ensure yours is safe and accessible.

I was sitting in the cockpit of my friend Stan’s boat last fall, enjoying a cocktail with a couple of other friends as the sun slid below the horizon. It had been a great day on the water, and we were all waxing philosophic, impressing each other with what felt at the time like deep and meaningful insights on the state of boats and boating. Then Stan, a contractor who builds luxury homes, came up with this one: “You know, the engine room of a boat is a lot like the basement of a home.” Before any of us could ridicule his observation Stan explained himself.

“The basement gets no respect. It’s the place no one cares to visit except maybe the owner, yet it’s where most of the important stuff happens. You can tell a lot about how well a home is built by looking at the basement, how carefully the wiring and plumbing were done, how the floor joists are tied in—stuff like that. And you know, if you go into a man’s basement, you can tell a lot about what kind of a homeowner he is. If it’s empty or cluttered with boxes, he’s a guy who doesn’t do anything himself. If it’s messy, he’s probably messy in the rest of his life. And if it’s neat and well organized, he’s probably a high-end contractor, like me!”

Enclosed-Flybridge Engine Access

Well, apart from that last piece of self-aggrandizement, Stan convinced us all. In fact I think none of us ever looked at our engine rooms in quite the same way again, because an engine room really is a place that can define both a boat and her owner. But if you’re shopping for another boat or maybe just sprucing up the one you have, what makes a good engine room? Is it appearance? Neatness? Organization?

Product Placement

Of course it’s all those things. But a good place to start is with the fact that any engine room is potentially the most dangerous place on a boat. It’s full of hot surfaces, spinning objects, and toxic chemicals, so good engine-room design starts with a reduced need to go into the place, and ensures your safety when you do. 

The placement of things you are most often going to need to access as close as possible to the engine-room entrance means you will be able to get to them without actually going too far into the engine space. These things include switch panels, fuel-distribution valves, battery switches, and auxiliary gauge panels. Of course it’s difficult for engineers and designers to cluster all of these in the limited space that’s available, so look for the prioritization of things you’ll need to reach in an emergency. And, whether we’re talking the boat you own now or one you’re thinking of buying, make sure you keep earmuffs and other protective gear stowed near but outside the engine-room door.  

Engine-Room Aft

Go with the Flow

On virtually any boat, the placement of the raw-water strainers near an engine room’s entrance, either abaft the engines or ahead of them (depending on the location of the entrance), can make the task of checking them, and closing the seacocks in an emergency, easier. And speaking of emergencies, if your engine room is equipped with valves that allow the engines’ raw-water pumps to draw from the bilges instead of the outside water—in other words, crash pumps—the system may be of limited use if you have to make your way forward and then grope for a submerged lever because the engine room is partially flooded. Flagging its location is a good precautionary measure. As is ensuring that there’s a screen of some description over your crash-pump pickup(s)—sopping wet dirt and debris make for very poor engine coolant.

You might also think of flagging your fuel-water separators, whose clear settling bowls should be frequently checked for signs of contamination. These are often placed on the forward firewall and often near the valves that control which fuel tanks the mains and genset draw from and return to. On some boats, these valves are crucial and require periodic adjustment to ensure good running trim, but of course that means that some crewmember has to negotiate the passage forward between two hot engines to change them, at least on boats with engine-room access aft. If your main fuel tank is amidships and forward of the engines, as it is in many boats to ensure relative constant running trim as fuel burns off, it may have been impractical to place both the separators and the fuel valves anywhere else. The same applies to sight gauges, although if a boat is equipped with saddle tanks, placement aft may make them visible from the engine-room entrance. One simple way to deal with the dangerous transit between hot engines, of course, is to make sure you’ve got a central handrail overhead. And perhaps stow gloves along with your earmuffs outside the engine-room door so you don’t fry your hand on a piece of hot stainless.

Let There Be Light

Sooner or later someone is going to have to go inside the engine room while the boat is underway, so good design should focus on minimizing the time required to do whatever job is necessary. The first step toward accomplishing this is good engine-room lighting, which hopefully will be controlled by a switch as close to the entrance as possible. The rule for lighting is pretty simple: the more wattage the better. But even when there’s plenty of light, fixtures are often placed right over the engines, which is great if you happen to be working on valves or injectors but not so helpful if you’re trying to trace a fuel or water leak. An engine room that’s finished in high-gloss white paint will reflect the available light into a lot of nooks and crannies, but ultimately a portable trouble light or flashlight may be required. Many boats are also equipped with separate emergency engine-room lighting that operates on a different circuit, usually on a much lower voltage. This is fine but often the system is significantly less powerful than the main system and lacks the illumination required in an emergency. Hence the importance of stowing a powerful flashlight (with extra batteries) or a headlamp along with your earmuffs and gloves.

Precise Placement 

Whether someone enters an engine room in an emergency or just for a routine check underway, there are aspects of the space’s design that can make his job easier. 

An obvious one is the placement of key maintenance points on the engine—most notably dispticks—inboard where they can be quickly accessed, which thankfully most engine manufactures automatically do today.Most engines today are also equipped with remote coolant reservoirs, which allow you to check engine-coolant levels without the hazard of removing the engine-mounted pressure cap. But on many boats, these reservoirs are difficult to see because they are placed wherever there’s a bit of free space—if such is the case on your boat (or your prospective boat), consider moving them to a spot where you can see them most conveniently and quickly, perhaps near the central walkway. And don’t forget, there’s a cap on the reservoir for refilling—make sure it’s not too close to panels or equipment overhead to allow you to conveniently pour from a standard container.

Bertram 511 engine room

Fashion vs. Function

And speaking of that walkway between the engines, I’d like to take this opportunity to vent a personal frustration. Everyone loves the shiny diamondplate panels that typically cover this walkway. They really add a classy touch to a finely fit engine room. 

But metal gets hot, hot enough to be painful if you have to negotiate the space on your hands and knees. And metal—even with the diamondplate surface—can be slippery when it’s wet or oily. 

Custom-Line 124 engine room

Rubber, on the other hand, reflects little heat and offers superior traction when wet or oily. Yes, it’s not nearly as pretty as diamondplate, just more practical.And, by the way, even if the boat you want to buy has metal diamondplate in her engine room, you may be able to cover it with a non-slip-backed rubber mat or mats. Some of the stuff even comes with a diamondplate-like surface.

Bertram 800 engine room

Step Carefully

Just moving around in an engine room can be challenging. The two engine areas that present the greatest potential hazard in an engine room when the boat is underway are the two places where things are moving—the front and the back. Today almost all engines have metal guards covering the forward moving parts, but not aft, where the propshaft meets the marine gear. On a proper vessel, there is almost always a shield or cover over this area, usually hinged so there’s still good access. This can be particularly important in an emergency when a crewmember may have to clamber over and around the engine to access the outboard side. If the propshaft is exposed and turning, the potential for injury is high.

Space restrictions on any given boat are one of those things that is imposed on the designer—he can’t provide more headroom or width between the engines than the basic vessel envelope allows. But even in a tight space, there is much that can be done to make passage forward easier, particularly by making sure there are no projections  into the walkway, be it from the engine or from some other piece of equipment, like a valve handle from an oil-change system or fuel-water separator. The same is true of the overhead. I was recently in an engine room in which one of the nozzles for the fire-suppression system was directly over the walkway; admittedly it was protected by a wire cage but nothing protected my bare head from the cage when I failed to sufficiently hunch over.

The Heavyweights

One final consideration when you’re looking at the engine-room design of a new boat is where the manufacturer has put the heavy stuff—namely the batteries and the genset. Here both space constraints and trim considerations have probably ruled the day—a designer needs to keep weights evenly distributed side to side and position mass well aft to allow for good planing performance. As a consequence we often see batteries as low in a boat as possible, not infrequently under that beautiful diamondplate. This isn’t ideal—the bilges are the first place to flood—but it’s a fact of life. So the prudent boater should think about equipping his vessel with a dedicated emergency battery (if she doesn’t already have one) that can run his VHF and other key electronics, and mounting it as high as possible. That way, when everything else has failed, you can still determine your precise position and put out a proper distress call. This practice is de rigueur on commercial vessels, incidentally.

As for the genset, the typical location is as far aft in the engine room as possible—often under a stairway or cockpit. There’s nothing terribly wrong with this, as long as you accept the fact that extracting said unit should it require major surgery is going to be costly. Virtually all modern gensets have “single-side servicing,” meaning the dipstick, oil fill and drain, and hopefully the raw-water pump, are all on one side. This is great for maintenance convenience, as long as the unit is mounted so the service side is really accessible, which it often is not. That’s likely to mean that you-know-who is not going to bother to check the oil level as often as he should. Of even greater concern are the genset’s remote coolant reservoir and fuel-water separator. These need to be out in the open where they can be quickly checked visually. If they’re over in the corner behind the A/C system and not accessible, they’re basically useless.

So, in conclusion, I’d say access is really what good engine-room design boils down to. It’s about a space that’s designed so that, although you don’t go there unless you have to (by the way, we do recommend periodic engine-room checks while underway), when you do you can accomplish what you need to as quickly and safely as possible. You know, just like your basement.

This article originally appeared in the July 2013 issue of Power & Motoryacht magazine.