Power Required Calculator, Semi-Displacement Hull

Enter both values Desired Speed and Displacement speed. These are used in Wymans formula to calculate estimated power required for the vessel.

Displacement

See Hull Displacement definition .

Desired Speed

This is the maximum speed that you require. Note, there are other factors, such as safety, not covered by this calculation that would limit desired speed. Contact the designer manufacturer to find out what the vessels maximum SL Ratio is.

Power Required Results

The results show the estimated required power at the shaft. Note that engines are rated differently for inboard diesels. For example SHP is approximately 95% of BHP due to losses in the transmission, to ancillaries etc.

Power Required Chart

This shows the SHP required for a % of hull speed.

Also see:

Boat Hull