Sailing surfboard with stern fin - uses U=section fin element glued by its base into central groove in after portion of board underside

摘要

The surfboard, partic. a sailboard, has a stern fin. This fin (4) is conventionally mounted centrally under the stern, but consists of a baseplate (4c) and two side stabilising plates (4a,4b). The fin is pref. made from U-section bar, and is inset into a guideway (3) in the board underside extending from forward of the daggerboard slot (5) to the stern: it is pref. secured adhesively. The stabilising plate leading edges are raked and the trailing edges are perpendicular to the base, to improve flow. The stabilising plates may be linked by a flat plate to form a tunnel; the flat plate may extend outboard of the two side fins.