[Fr. Frank]

Sweet numbers! That sucker is FAST!

Very interesting that the boat seems to do the best mileage once it is up to a solid plane and mileage falls off from there, on through the range where most boats are more efficient and then climbs again. Does the boat feel like it is getting higher in the water as you approach 4000? Maybe better mileage from less surface drag?

Also, if you're using hydraulic steering, and assuming the motor is mounted at the correct height, to achieve maximum efficiency at cruise or WOT, your trim angle should be adjusted out/up until the propeller just begins to ventilate, and then trimmed back in until the excessive slippage stops and you get full bite again. The idea is to have the propeller pushing as nearly parallel to the surface as possible.

If you have single-cable steering, (assuming you have the correct torque tab installed), trim up-out until the steering torque is completely neutral, i.e.; you can let go of the helm in calm water and the boat will continue to steer straight/track the same heading.