FOUR STROKE 150 HP DATA

Sailboat,

-- 4000 RPM 40 MPH (MPH is GPS WAAS, no current)
-- 4600 RPM 46 MPH
-- 56OO RPM 45 MPH (wide open throttle)
-Red Line RPM is 6000.

Sailboat -- How is that possible ??? Is this all with the same prop? What prop specs?

MPG IS FABULOUS :)