Try the Boat Speed Calculator
I created the boat hull speed calculator, which has been surprisingly popular, based on some publicly available formulas I researched while trying to figure out what size engine and propeller to use in re-powering my catamaran. I was surprised to see most of the information on this subject was fragmented and not very easy to understand or available. It occurred to me I could combing my programming knowledge with the knowledge I gained in this project and from speaking to a number of sources to create the calculator, free for public use, by anyone attempting to re-power a boat or anyone interested in the characteristics of boat speed. I used this calculator in my boat engine replacement and it was right on the money and I have received good feedback from visitors. Let me know if you have any suggestions or comments. There are a number of supporting pages created for the calculator that are worth reading.