Volkswagen Schwimmwagens used the engine and mechanicals of the VW Type 86 four-wheel drive prototype of the Kübelwagen and the Type 87 four-wheel drive 'Kübel/Beetle' Command Car, which in turn were based on the platform of the civilian Volkswagen Beetle. Erwin Komenda, Ferdinand Porsche's first car body designer, was forced to develop an all-new unitized bodytub structure since the flat floorpan chassis of the existing VW vehicles was unsuited to smooth movement through water. Komenda patented his ideas for the swimming car at the German Patent office.