How to Trim Sails provides practical advice that will instruct both the beginner and experienced sailor. As fuel is to powerboats so sails are to dinghies - you won't get far without one. Knowing the effects for various controls on the shape and performance of the sails can make a huge difference, and Peter Schweer lends years of experience to the task. The rigs included are masthead, fractional with swept spreaders, fractional with runners and dinghy with swept spreaders.