Stardrives contains statistics for a wide variety of slower-than-light drives, given how much time scientists and authors have spent exploring their feasibility, but solar sails are unique among them. For one thing they are considerably faster when pushed by a laser projected from another ship or station than relying on natural sunlight. For another that sail makes them a much bigger and less maneuverable target when deployed, in game terms they act as if two size categories larger. They can retract the sail if they suddenly find themselves in combat, but that takes time.