2-19-01
PLANING BOAT SPEED CHARTS
"How fast will it go?" is a frequently asked question. There isn't a simple answer, as many factors must be considered. However Chart 1 will provide a rough estimate of the potential speeds possible for a typical planing boat.
Chart 1
The chart is based on pounds per horsepower, a factor obtained by dividing the gross weight by the shaft horsepower. Note that "gross weight" is the total weight of the boat as it would be fully equipped with passenger(s) on board ready to go. Don't overlook the fuel (6.2 lbs. per gallon) and ANY extra gear carried. After figuring the total weights add a 10% safety factor.
To use the chart, locate the gross weight divided by the shaft horsepower factor along the bottom of the chart. Go upwards from this line to the "average planing hull" curve and read the speed in mph.
Note how important the weight factor is in a planing boat, and the smaller the boat the more important it becomes.
Chart 2
As an assist in determining gross weight Chart 2 indicates the weight of a typical outboard motor based on the horsepower. The weights are an average taken from several outboard motor manufactures and included four cycle types.