My 46 Race skater weighed right at 7k, but I don't think the 980 number is right.

Remember these are Sterling motors, he was doing some crazy stuff with Open motors.

Yahoo

on the dyno the motors made 983 hp each. boat was the heaviest in the class but you have to remember that a race boat and a pleasure boat are two different animals. if we ever got below 5800 rpm we were out of the race. also when you get enough air under the boat the theoretical weight goes way down as the lift goes up. motors spent an hour at a time running on the limiter at 7800 as back then we ran 10 to 15 mile laps with only a couple turns. 5 or 6 miles on the limiter makes for a lot of air up under her.

WOW 7800 is good going for that duration, how do you think the Skater will perform with he extra weight? the package will be around 23-2400 lbs. a side.

The CG is going to be vastly different to the gas setup, will it be best to keep the motors forward as far as possible.

What's the average weight of a big cube blower motor, gearbox & #6 14-1500lbs?

My guess is about 1800-1900 lbs a side for a blown BBC, trans, and ssm6.

CG will be the key. we usually ran with some weight in the nose even in calm water to get it balanced the way we wanted. if I remember correctly I weighed one of our blower motors once and it was around 1350 lbs but I dont remember if the crashbox was on it. the issues with the diesels will be how far you can go forward to get the balance back. of course with the wood in place of the balsa that changes things also. I used a CG calculator for light aircraft to know how much weight to move where to get what I wanted.

The large useable RPM range of those gas motors are part of the reason it worked. Very good turn down ratio from max RPM to min idle speed. Gas engines have a big advantage over diesels for this reason.

That's were diesels are happy 80-90% of there max power all day long, Is that not the idea of a performance boat? I would have thought this is the range that most of these boats operate in.

I own range of performance boats and when out we are either at idle through no wake zones or running any were from 70% max power up over.

What I'm saying is that the gas motor can idle at 12% of WOT. So they can still plane off and go fast on the big end.

What do your diesels idle at and redline at?