The following calculator is based on the equations and formulae in chapter 3 of "21st Century Multihulls" by Joseph Norwood Jr., available from Multihulls Magazine
Chapter 3 deals with hull resistance. The aim is to derive simple mathematical formulae for the design of minimum-resistance hulls. The formulae can be used either for non-planing displacement hulls or for multihull outriggers. It is assumed that the front section has semi-elliptic plan and exponential profile, while the rear section has exponential plan and semi-elliptic profile. The theory may not be valid for sections which differ significantly from this. The theory divides the hull into 2 sections of equal volume (but usually different length), makes calculations for each half, then adds them together.
WARNING - Do NOT use the AYRS edition of this book. It is full of typographical errors. The publisher's long-delayed 8-page errata sheet only covers some of them. You would not want YOUR boat to be "nearly" right apart from unknown, random errors, would you ?
or (if you have a java compiler), the source Fred.java
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