Takes the reader step-by-step through the stages of designing both power and sailing boats, whilst also explaining the reasons behind the procedures. Throughout, line diagrams and reproductions of working drawings are used to help understanding and allow the reader to see typical lines plans from a wide range of vessels. The usual calculations employed in all boat design work, requiring only very basic arithmetical skills, are set out and typical examples worked through. In addition, speed/power tables are given for motor boats as well as a method for checking "balance" under sail.