Boat Buying Decision: One Engine or Two?

If you’re like a lot of boaters, you can become afflicted with “two-foot fever,” a malaise that grabs hold of you and makes you think how much happier you’d be if your boat were two feet longer. Well, it happens even after you get the boat you thought would cure 2-foot fever, and before long the boats you are looking at are topping 30 feet in length, at which point you might have to decide whether you want one engine or two.

It’s a tough question, because it involves many variables such as fuel consumption, maintenance costs, and other expenses. The real issue is what it will be like on the water. Personally, I prefer twin engines, especially for boats that are run in the ocean or in other large bodies of water. With twin engines, a problem with one engine doesn’t mean you can’t get home.

Thirty feet is about where the decision comes into play with sterndrives. For outboard-powered boats, it starts around 26 feet or so.

When it comes to maneuvering around the docks, nothing beats a twin with the propellers rotating outward. A single-engine boat with a dual, counter-rotating drive, such as MerCruiser’s Bravo Three or Volvo-Penta’s DuoProp, is good, but they tend to push the boat a little faster at idle speeds. That isn’t so handy for docking.

A twin-engine boat operates with less load on the engines and requires less rpm to reach reasonable cruising speeds. In terms of fuel economy, I have heard of a pair of fuel-injected small-blocks attaining better fuel mileage than one large big block. Twin outboards will in most all cases use more fuel than a single engine.

If you find yourself looking at boats in the size range where there’s a decision point about one engine or two, it’s tough to beat a twin-engine setup. Run your numbers, look at long-term costs, and if you can afford two, go for ‘em.