Graupner,Hydro-Antrieb,1781

Hydro-Antrieb Graupner 1781 Fully assembled. The deflection of the unit should not exceed 10-15º at high speed. The shaft with sterntube which transmits the motive power to the HYDRO drive is lead out at the transom of the boat. An adjustable arm incorporated between the main member and the mounting bracket permits adjusting the angle of the driving shaft for top speed conditions.Electric motors of up to 200 watt or combustion engines of up to2 cm3 displacement are suitable for installation. Dimensions (nom.) Length 60 mm, height 90 mm, M4 shaft thread.

This novel propulsion system is used to drive and steer boats of the hydroplane type. Thrust is provided by a HYDRO surface-propeller which operates semi-submerged in the water, when the boat is planing. Semi-submerged propellers are mainly used on fast racers. In the case of model boating they are tethered-running NAVIGA A class racers, HYDRO racing boats and catamarans. The blades of the semi-submerged propeller, immersed at one time of a revolution, above the water in the next one, throw up a most impressive plume of spray water behind the boat, sure sign of optimum propeller efficiency.