Signature 650F with a 225 Suzuki 4 stroke, top speed 5900 rpm 39 knots on the GPS cruise at 3600 rpm for 21- 22 knots fast cruise 4200 rpm 26-27 knots. Fuel usage is fairly constant across the cruise speeds at 1.1-1.2 litres per nautical mile. It is interesting to see the differant way that people measure fuel consumption. I like to measure the distance travelled for the fuel used as this is a true measurement for the distance travelled. To quote per engine hour is not that accurate if a lot of trolling is involved or just idling around looking for a bottom feature etc.