Saw this post on another forum. Thought it was interesting:

3 boats, Sailfish marina Stuart Fl to Grand Cay Bahamas, about 110 miles give or take a few. all ran together 22-27 mph as conditions changed. 27 tiara open w/270 Crusaders - 87 gallons, 26 Grady Tigercat w/ 200 fourstrokes- 87 gallons, 248 Mako w/a w a single 300 hpdi - 76 gallons. I thought those old low tech Crusaders would suck down twice the gas as those new tech Yamahas. I guess not