From the introduction: The PCs play living boats. No one knows how or why the experience the world as a boat... They just do. Some are happy to live as boats and go about boat-life with great enthusiasm. Others are saddened by this strange existence, forever drifting with the whims of the sea. There are no humans on the boats, except on the mystic boat (and there, humans are treated as traits or tools, not as characters with rich personalities). The boats are propelled either by engines, sails, or oars. PCs are free to imagine their boats from any era; for example, there may be a longboat, a steam-powered paddleboat, and a jet ski in the same party. There is no need for any realistic approach to creating and operating the boat: a Viking drakkar might ram a modern cruiser warship, and still win the battle.