[QUOTE=spectras only;3779957]Dave's quote is pretty close. His boat is 27' , mine is 25'7. His quote 8-12 gal/hr average, [don't know at what speed] my average is 8 gal per/hr at 3000 rpm, cruising at 40 miles per hour, going to 20 gal/hr at 5000 rpm, 75mph on the GPS Gaffrig speedo.
I'm sure Dave meant 8-12 gal/hr per engine.

I limped back to the launch ramp on the port engine when this happened. A testimony for having twins and external rams to keep the drive pulling out

I check my fuel burn at each fill up. I average 8-12 gph total for both engines. I am boating on Lake Havasu and there is a fair amount of ideling in and out of the harbor, so that lowers the fuel burn. If I just go to Catalina and back so it is all cruising (usually 3000rpm) which is about 43mph my fuel burn is 15 gph total for both engines. That is about 2.5 mpg.
The boat is pretty light and therefore not the greatest for rough water, but it does perform well. Top speed is 5200 rpm and that shows 82 mph on the pitot speedometer, but the Nav GPS shows it to be more like 75 mph. If I run it hard, which I have only done one time 4,000 rpm is 60 mph on the speedo, don't know what the gph would be.

The boat you pick will depend on what you want to do.

I had a 29 Kryptonite and with a single 550hp motor saw low 80's all day long.

The Kryptonite was a low slung sit down boat that was light and had a basic cabin. It ate up rough water and the race boats dominated the F1 class so you know it is a great handling/running boat. That said, it does not have the cabin or the entertaining space of a Formula, Baja, etc.

If you want a big cabin and more luxury ammenities than the size and the weight go up and you will probably need a twin engine boat. Double engines require double maintenance but also provide the security of getting home on your own power.

Any way you look at it, you can't put a price on FUN. And being on a boat with 1 engin or 2 is better than being on shore!!!