The invention relates to the field of shipbuilding, in particular to reversing and steering devices of waterjet propelled ships.

A reversing and steering wateqet propulsion unit comprising a reversing flap pivotally hinged on a horizontal axis behind the duct is known. The reversing device is mounted onto the portions of the waterjet propulsion unit (RU, Cl, No. 2534500, 2014).

The disadvantages of the prior art solution are low efficiency and design complexity.

A curved astern water conduit mounted on a horizontal axis (RU, Cl, No. 2659367, 29.06.2018) is the closest analogue to the claimed device.

The disadvantages of the known solution are low efficiency due to hydrodynamic losses at the time of changing the direction of the propulsive jet when moving astern and design complexity.

The claimed invention is directed to increasing the propulsion unit efficiency by reduced hydrodynamic losses and simplified design.

Said technical results are achieved by the fact that, in the reversing and steering wateqet propulsion unit comprising a deflector and a reversed curved astern water conduit pivotally mounted in a vertical plane, the deflector accommodates a ship control pivot head, the astern water conduit is made tubular and directly mounted on the pivot head underneath outlet thereof by means of an eye attached to the outer surface of the pivot head and a bracket interacting with the lateral surface of the tubular solid water conduit, wherein, in operating position of the water conduit, the edge portion of the control head is located in the inner cavity of the curved water conduit.

The outlet end portion of the reversing tubular water conduit is made rectilinear.

The astern water conduit is designed integral with a hydraulic plate.

An annular cutting out is provided in the inner cavity of the end portion of the reversing water conduit, the inner cavity of the end portion in the operating position is in contact with the outer surface of the edge portion of the control head, the diameter of which is larger than the outer diameter of the pivot control head.

The claimed invention meets the patentability criterion of "novelty", because the search did not reveal a source of information from which a solution would be known that matches the set of features of an independent claim.

The implementation of the claimed invention does not contradict the well-known laws of physics of mechanics, and was also tested on prototypes of special equipment, therefore, one may confirm the compliance thereof with the patentability criterion of “industrial applicability”.

Since no known sources of information provide the practice of placing a water conduit on a pivot head such that pairing of the former with the outlet of the latter is provided for moving astern, the proposed technical solution meets the patentability criterion of“inventive step”.

Fig. 1 shows a general view of the wateijet propulsion unit in the "ahead and astarboard" position; Fig. 2 is a general view in the "astern and aport" position; Fig. 3 is a longitudinal section at the time of moving ahead; Fig. 4 is a longitudinal section at the time of moving astern; Fig. 5 is an option of combining the water conduit with the hydraulic plate.

The claimed reversing and steering waterjet propulsion unit is mounted on the transom 1 of a river or sea ship and comprises a deflector 2 with a pivot head 3, on the outer surface of which a tubular reversing curved astern water conduit 4 is pivotally mounted, the output section 5 of the water conduit 4 is made rectilinear. The water conduit 4 in cross section can be made of any shape: round, rectangular (square), oval, etc.

The water conduit 4 is placed under the outlet of the pivot head 3 by means of a pair of brackets 6 and eyes 7 hingedly connected to each other.

In order to turn a ship, the head 3 provides a protrusion 8 interacting with a tie rod, cable, servodrive (not shown).

One of the brackets 6 is equipped with a lever 9 for controlling the water conduit 4, the lever 9 interacts with a cable, tie rod or servodrive (not shown), by means of which the water conduit 4 is rotated to change the "ahead/stop/astem" movement mode.

The end portion of the pivot head 3 at the time of rotating the water conduit 4 to move the ship astern is placed in the inner cavity of the end portion of the reversing water conduit 4. For a tighter connection of the pivot head 3 with the water conduit 4 in the inner end portion thereof, a cutting out (groove) 10 with an elastic sealing gasket (not shown) is provided. The diameter of the annular cutting out of the water conduit 4 is slightly larger than the outer diameter of the control pivot head 3.

A hydraulic plate 11 is mounted at the lower end edges of the brackets 6, the hydraulic plate 11 is designed integral with the astern water conduit 4. The hydraulic plate 11 can be located both below the astern water conduit 4, and can be integrated in the middle portion thereof, i.e. combined with each other.

Stiffening ribs 12 parallel to the longitudinal axis of the water conduit 4 are mounted on the lower surface of the hydraulic plate 11. The hydraulic plate 11 is placed in the recess of ship's hydroski 13, the cantilever part of which extends beyond the transom 1.

The device operates as follows.

When the ship moves forward by transmitting force to the protrusion 8 by the drive, the head 3 is rotated and, as a result, the ship maneuvers by controlling the thrust vector. When moving ahead, the stiffening ribs of the hydraulic plate 11 play the role of additional rudders, and the hydraulic plate 11 itself improves the hydrodynamic properties of the ship in the planing mode, the water conduit 4 having no contact with the outlet of the pivot head 3.

If necessary, the water conduit 4 in the eye 7 is rotated by acting on the bracket 6 through the lever 9, thereby placing the groove 10 of the water conduit 4 on the outer surface of the end portion of the pivot head 3, the gap is sealed with an elastic gasket, thereby changing the direction of movement of the outgoing water flow from the deflector 2 of the propulsion unit to the direction of the bow of the ship. The ship thus moves astern. Since the astern water conduit 4 is attached directly on the pivot head 3, the rotation of the pivot head 3 provides astern maneuvering by controlling the thrust vector, whereby the hydraulic plate 11 acts as a wave baffle.

To implement the "STOP" mode, a partial rotation of the water conduit 4 in the eye 7 is performed, at this time the propulsion jets balance each other at the time when the jet propulsion unit operates.

When the hydraulic plate 11 is mounted at a negative angle, the hydraulic plate at the time of moving ahead performs the role of an adjustable trimmer.

In the process of changing the position of the device to astern movement position, a the time of moving ahead, the hydraulic plate 11 acts as a dynamic brake.

The middle position of the device corresponds to zero thrust at the time when the waterjet propulsion unit operates.

Trimming is performed as follows. In the planing mode of ship's movement, the operator, using the reverse control drive, smoothly changes the inclination angle of the hydraulic plate 11 to negative values, whereby the front of the hydraulic plate rises into the recess provided in the hull of the ship, and the rear of the hydraulic plate 11 falls beyond the overall cross section of the ship's hull, whereby the recess in the ship's hull forms a stem redan such that the incoming water flow creates excessive pressure at the rear of the hydraulic plate 11, thus providing a lifting force that is transmitted through the points of attachment of the reverse to the transom portion of the ship 1.

The dynamic braking mode is performed as follows. When changing the position of the reverse to the“zero” or“reverse” position in the planing mode of ship's movement, the front of the hydraulic plate 11 goes beyond the overall cross section of the ship's hull, whereas the rear portion rises. The hydraulic plate 11 with the front portion thereof captures the oncoming flow of water and directs it upward at an angle, thus providing a braking effect and negative lifting force that, through the mounts of the reverse, acts on the stem portion of the ship, thereby preventing the bow of the ship from deepening.