Re: Fuel Efficiency
I guarantee that a diesel will be more efficient in any application, as long as they are not super duper heavier or worse. However, it may not be more economical . . . Let's say you got something with equal horsepower (diesel) at $25,000 more. Let's say that boat gets 1.2 MPG with the Gas engine at cruise and the diesel got 1.5 This is not the whole story with efficiency because diesel has more btu's per gallon, so even at equal efficiency btu for btu, the diesel will automatically go farther as the gallon holds more energy, however, when I say more efficient I mean more thermal efficiency, so you get a double whammy, efficiency and more energy per gallon. 1.2 to 1.5 is still under 25%, and I think conservative.
Back to the point, so let's say you run 100 hours a year, and you are burning 19.15 GPH with Gasoline and 15.3 for the diesel (your 23 MPH cruise), So over the year you burn 1915 and 1530 gallons and say $3 each. That's $5745 and $4590. A savings of $1155 per year and you pay it back in 21 1/2 years . . . Yes I know this doesn't take into account the resale benefit, but it also doesn't take into account putting that $25K into some other investment . . . Diesels work in commercial applications because they run 2000 hours per year, and they are better for safety, but they are not economic for a pleasure boater IMHO. I've sold diesel engines my whole career, love them, breath them, but numbers are numbers . . .
