Abstract: The invention relates to an electric rudder rotor which in its simplest construction is in the form of an externally running underwater electric motor and comprises a fixed stator and a rotating rotor, which carries the rotor cylinder, the stator being supplied with electric current and the rotor being rotated by magnetic interaction between the stator and the rotor.

Abstract: A rudder assembly for marine craft wherein the main rudder carries one or more fins pivotable as well as lockable in relation to it, wherein the actuating and control devices for the fin are integrated with the rudder assembly.

Abstract: A rudder assembly for marine craft wherein the main rudder carries one or more fins pivotable as well as lockable in relation to it, wherein the actuating and control devices for the fin are integrated with the rudder assembly.

Abstract: The invention relates to a method for producing a thrust in manoeuvering engines for watercraft and a manoeuvering engine constructed for the same, whereby the method comprises the annular driving water jet supplied to the diffuser and enveloping a first suction water jet is fed to a second suction water jet supplied to the diffuser inner wall surface, while the manoeuvering engine is constructed in such a way that the rear part of the engine casing is provided with an inlet port having a smaller diameter than the outlet port and located in the vicinity of the outlet port of the front engine part, whereby for the optimum adaptation of the exit mixing jet velocity to the vehicle speed a water jet exit cross-section regulating device is provided.

Abstract: The invention relates to a rudder for aquatic craft wherein the rudder member is provided with a fin which is pivotable independently thereof and with a rotor on the front edge of the rudder member and/or between the latter and the fin or between the rudder member and a guide member mounted in front of said rudder member.

Abstract: The invention relates to a gas-driven pulsating water jet propulsive duct drive for watercraft with a propulsive duct which has at the front end an inlet aperture for water with a closure member closing and opening periodically by means of a drive device, is open at the rear end for ejection of water and comprises at the front end a power gas outlet behind the inlet aperture. With propulsive duct drives of this kind the forward inlet aperture of the water-filled propulsive duct is periodically closed, the power gas outlet opened, in order to feed power gas under pressure into the propulsive duct and to expel the fluid filling of the propulsive duct rearwards, the power gas outlet is closed and the forward inlet aperture opened again for a fresh fluid filling.