Abstract: The invention relates to an intermediate support, intended in use to be fixed on the transom or stern of a boat and carries at its free end facing away from the transom a clamping board or plate, on which can be fixed a standard production outboard motor. The intermediate support is provided with a pivot bearing having a vertical or slightly inclined axis, so that the clamping board carrying the outboard motor can be swung to such an extent from a first position, in which the clamping board is disposed parallel to the transom of the boat, to a position in which it extends, for example, parallel to the length direction of the boat. As a supplementary feature, the clamping board of the intermediate support may be adjustable in height.

Abstract: The invention relates to an accessory for outboard motors, Z-drives for boats or the like, the exhaust gas of which is normally conducted through the propeller hub into the water. By means of a valve system, which is suitably automatically changed over by the direction of rotation of the propeller, the exhaust gas, during rearward rotation of the propeller, is conducted to a region which lies outside the propeller suction, while the exhaust gas, during forward rotation of the propeller, flows out in the usual manner through the propeller hub. The success of the invention lies in a significant increase of the propeller propulsion during rearward travel.