Simply input the boats know details and the software will do the rest. Performance calculator is great for working out the unknown factor like boat speed, engine rpm, gear ratio, propeller pitch and efficiency.
In this example the unknown factor calculated was Boat Speed. The engine RPM, gear box ratio, propeller pitch and efficiency were keyed in and the Boat Speed was calculated.
Prop Tools Performance Calculator will calculate the unknown factor when the other four factors are known.
Calculate Engine Revs 
Calculate Gear Box Ratio 


Calculate Propeller Pitch 
Calculate Propeller Efficiency 

