PROPULSION SYSTEM FOR SURFACE VESSEL WITH OUTBOARD ENGINE Russian patent published in 2021 - IPC B63H5/16 

FIELD: shipbuilding.

SUBSTANCE: invention relates to shipbuilding. The propulsion system of a surface vessel with an outboard engine contains a propeller-like blade propeller fixed to the shaft. The propeller is equipped with two sections of the protective guard, attached through the mounting plate to the anti-cavitation plate of the engine and to the propeller gearbox. One of the sections is located in front of the propeller and is connected to the second section by means of spacers. One section consists of an annular guide nozzle having a smaller diameter than the propeller. The second section is made in the form of an extended annular profiled guide nozzle enclosing the propeller and is located along the propeller axis so that its inlet section is spaced from the propeller disk upstream at a distance of at least 0.14 of the propeller diameter. The inner side of the nozzle is substantially flat and curved outward. The chord of the nozzle profile is oriented at an angle of 1-3° to the propeller axis. The propulsion system includes mounted on the annular guide nozzle housing and located behind the propeller a circular blade straightening apparatus. The apparatus contains blades located around the guide nozzle, and located axisymmetrically with the propeller a circular ring with a diameter of at least 0.4 of the propeller diameter. The blades are closed on the ring, which are installed in the guide nozzle at an angle of 70-75° to the propeller axis. The blades are in the form of a parallelogram with oblique angles. The blade profile has a length of not more than 0.22 of the propeller diameter. The trailing edges of the blades are located gradually beyond the cut level of the guide nozzle in the radial direction and form an acute angle with the housing of the blade, which belongs to the generatrix of the said circular ring. The leading edge is spaced from the propeller disc by 0.35-0.45 of the propeller diameter. The number of blades of the apparatus exceeds the number of propeller blades by at least one to reduce unsteady forces at the blade frequency.

EFFECT: invention increases efficiency of the propulsion system and the possibility of using guide nozzles with propellers of outboard motors of different power ranges having different longitudinal lengths.

3 cl, 2 dwg