MAXIMUM SPEED PREDICTION

for a

POWERBOAT

Here is something a little unusual, at least we haven't noticed this free estimated speed prediction elsewhere on the net, and we probably never will since we derived it ourselves. This page predicts the maximum speed of a "normal"  monohull powerboat given the waterline length, the nominal power installed and the displacement. It is reasonably well tested on inboard boats with conventional drive system. Enter your input information in the next three white boxes; press the appropriate (English or metric) button for calculation; then view results in the white boxes below the buttons. Regardless of whether English or metric units are used, be consistent (in other words, use all metric or all English input) and click the correct button.

Waterline length  =  

 feet or meters

Displacement  =  

 pounds or kilograms

Installed nominal power*  =  

 HP or kilowatts

Predicted maximum speed **  =  

 knots

Speed very unlikely to be less than  =  

 knots

Speed very unlikely to be more than  =  

  knots
* The "nominal power" is that given by the engine manufacturer or the builder. No overt attempt is made to get the actual power at the propeller. Be sure the power from all drive engines are added together.
** Predicting speed with only three numbers used to describe a boat's speed potential, as is done above, is bound to be inaccurate because the analysis is too simple. However, it does enable one to make a speed estimate from data often found in brochures and we have checked a large amount of data for monohull pleasure boats over 25', with inboard engines and conventional drive systems, built for family and/or fishing use and found that there is very nearly a 100% chance that the correct answer for the boat speed lies between the high and low values given above. For the type of input used, we believe that this is about as close as one can can get. If more accurate results are sought using arithmetic, more data must be provided, and a better calculation method used. We recommend seeing a naval architect or the boat builder for more detailed analysis. Or, if the speed potential of a particular boat is sought, it is sometimes easier and more accurate to go find an example of the boat in question and talk to the owner/operator.

Contact Sassafras Yacht Sales:

 

Telephone e-mail
410-271-3311 yachtbroker@earthlink.net
click next line for driving directions to sales office
77 George St. Georgetown, MD 21930 USA

(mail to: P. O. Box 36 Georgetown, MD  21930  USA)