This paper discusses briefly the theory of sail power and its application to fishing vessels, and examines theoperational requirements of a variety of fishing methods and the conditions under which sail power can be used in each method to reduce energy consumption. Fishing methods are listed in descending order of utilization of sail. Traditional working-sail configurations and the development of newer systems are examined in detail and their applicability to present-day fishing vessels discussed. Explanations are included of practical details of rig and sailhandling for large and small inshore and coastal fishing vessels. Finally, the economics of sail power are examined and costs and maintenance are balanced against expected energy saving.