J/30 Class Association Forums J/30 Forum Cruising Discussions Preferred cruising RPM ?

Dominique - there is an older post that has the Yanmar power curves. Look at the slope of engine power at the prop versus RPM. Going from approximately 2400 to 2900 RPM doubles the power output. In fluid flow, (depending on the type of flow and some other factors), power is related to the speed cubed and fuel consumption is linearly related to the power output. Theoretical hull speed on the J/30 is about 6.7 kts. Once you get close to that speed (in calm water), you're really burning fuel fast trying to go any faster.