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Hull Resistance Calculator

Awarded's Hot Calculator award, May 1998

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 ?

The theory and equations are copyright to Joseph Norwood
The Java program is copyright to Fiona Sinclair e-mail to:e-mail

Please wait patiently until a blank rectangle appears, then fill in the boxes and press Calculate.

This page is Java encoded. To view it, you need a Java capable browser.

If you can not see anything on your screen, try here

To run this off-line, you need to download the following:
Fred.class, Diagram.class, Gadgets.class, Matrix.class, Paper.class, Spread.class, Wireframe.class

or (if you have a java compiler), the source

PLEASE send me some user feed-back.

To all the people who have asked why I called it
It was named after Fred Schurch, who read the book but could not cope with the mathematics, then (very sensibly) mailed a discussion group asking for help. This program is dedicated to all other people who are in a similar situation.