The sail analysis code runs under Windows and is available on the Software page. The code solves the two-dimensional potential flow equation using a vortex panel method in which the vortex strength varies linearly along the panel and is continuous from one panel to the next. In addition, the code permits the specification of either rigid or flexible sails. The flexible sail option involves a solution of the “sail equation” and depends on the pressure distributions over the sails. The intended use of the code is to help users understand the fluid flow interaction between a mainsail and a jib. Note that since this is a potential flow solution, drag cannot be predicted.