Abstract: A steerable, self-propellable surfboard has a steering arrangement attached to a weight-bearing buoyant member such as normally forms a surfboard and arranged for being actuatable by a surfer lying prone on the buoyant member and permitting the surfboard to be maneuvered under control through a liquid in which the surfboard is disposed. The steering arrangement includes a rudder assembly arranged for changing a direction of travel of the surfboard, and a fin assembly which permits the surfer to propel the surfboard through a calm liquid body by causing the member to fishtail or undulate through the liquid in which the surfboard is travelling.