Start with repeatable test conditions
Record fuel load, passenger load, water conditions, wind, engine setup and other variables that can materially change performance. Use the same stretch of water when practical and run reciprocal passes when wind or current could influence results.
Compare the operating range
Peak speed matters, but so do time to plane, acceleration through the midrange, cruise RPM, steering feel and the engine’s ability to reach the intended wide-open-throttle operating range. A prop can trade one strength for another.
Calculate slip carefully
Propeller slip can be estimated when gear ratio, propeller pitch, engine RPM and measured boat speed are known. It is a useful comparison metric, not a direct measurement of wasted energy. Nominal stamped pitch can also differ from the effective geometry of a worked or lab-finished propeller.
Include vessel attitude and fuel data when available
Pitch and roll help explain whether a prop changes bow lift, stern lift or planing behavior. Fuel-flow data can support efficiency comparisons when the signal is reliable and the boat is held at comparable operating points. SmartTrim Prop is designed to synchronize these dimensions into a repeatable test workflow.