Horsepower is still horsepower. Don't get too hung up on torque in a marine application, very common mistake. Prop load curves are pretty linear so a high peak torque value only does one thing, decrease time to plane if you hammer it. If you usually run a boat of that size up slowly in RPM then a diesel will have very little effect positive or negative on performance. Weight considerations are an issue but not as bad as they used to be by a long shot. They are still heavier bhp to weight ratio at max ratings of either. Cost is a LOT higher.<br /><br />Fuel efficiency could be 30% better than with gasoline technology. This is a little bit of a complicated equation to figure out exactly how much better your fuel $ will be. The fuels are not equal in energy value (diesel has more) and they are not equal in cost per gallon (diesel is more) and the fuel efficiency across the prop load curve is of course variable, but the gasoline's engine relationship is different than diesel, they don't track up the curve equally . . . <br /><br />Obviously you would want to pay the difference back in fuel cost savings. If you only run 100 hours a year it won't happen . . .
I can help evaluate the payback if you are serious. Sounds like a real fun project . . . I love Bertys
<br /><br />tootoot,<br /><br />Yes sometimes an ECM will strand you, but the new electronics are VERY hardened, probably more reliable than mechanical now. There is nothing wrong with a good mechanically governed engine although the electronic engines will be better on fuel and diagnostics. Mechanical will be less expensive, but probably a poorer power to weight ratio.
