The DIY sailmaker can save as much as three-quarters of the cost of their sails by making them or re-cutting old ones, using little more than a tape measure, scissors and a domestic sewing machine. This work shows how the traditional rule-of-thumb methods of sail design can be updated with the aid of computer programs available by post. It describes the origins of the different shapes of sail and the practical differences between them in their handling and performance out on the water. It also explains design principles, the choice of sailcloths and shows how a basic home computer can be used to plot the panel shapes. The reader is then taken through the processes of lofting, seaming, sewing and tabling, and the hand finishing of details such as headboards, reef point, leathered corners and cringles. The book contains all the information a boatowner needs to design, make, repair and modify their sails.