Navigation & conversions
Knots to MPH & KM/H Converter
Convert knots to mph and km/h, or reverse the conversion, with instant results in all three speed units.
Open toolPropeller & performance
Prop Slip Calculator
Calculate propeller slip from engine RPM, gear ratio, propeller pitch and GPS speed recorded during your sea trial.
Understand your propeller slip.
01
Your inputs
02
Your result
Result updates automatically
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Slip is not propeller efficiency. A negative result calls for checking the inputs. Calculated pitch is theoretical, not a manufacturer-approved propeller recommendation.
Useful answers
Which gear ratio should I enter?
Engine RPM divided by propeller RPM. For a 2:1 ratio, enter 2. Check your gearcase documentation.
WHAT’S NEXT
Plan the next step.
Engine & fuel
Boat Fuel, Range & Cost Calculator
Calculate boat fuel range, running time and trip cost using US gallons or liters and your measured consumption per hour.
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