JP4305881B1 - Ships and barges - Google Patents

Abstract

[PROBLEMS] To improve the increase in resistance when moving forward and backward, which is a drawback of a circular hull, and to maintain the stability of the course while maintaining a smooth rotational movement due to the strong rudder, which is an advantage, by minimizing the hull We will provide small and medium-sized hulls to streamline material and construction costs. A large barge that can be used as a power unit capable of separating a ship is also provided.
An upper outer plate 9 has a cylindrical shape, a lower outer plate 10 provided below the upper outer plate 9 has a hexagonal column shape, and a propulsion device 23 that can be rotated in a horizontal direction is provided at a lower portion. A hull center line connecting opposing ridge angles of the side skin 10 is provided at a symmetrical position on the bottom of the ship with the axis of symmetry as the axis of symmetry. A downward opening type duct 17 is provided over the entire length of the bottom shell 12. In addition, skegs 18 and 19, fenders 36, bow and tail balls 47, and a propelling device 23 with a nozzle are provided. A U-shaped recess capable of accommodating the ship is provided in the tail of the large barge.
[Selection] Figure 3

Description

  The present invention relates to a ship, and more particularly to a ship whose outer periphery in plan view below a water line has a hexagonal shape. Moreover, it is related with the barge pushed by the said ship.

  Patent Document 1 discloses a berthing guide ship and a tugboat having an elliptical bottom. The purpose of this ship is to make it possible to tow and push in any direction.

  Further, the propulsion device using the pump water flow presented by the present applicant in Japanese Patent Application No. 2008-151345 is also used for the ship according to the present invention.

Japanese Patent Application Laid-Open No. 2002-331992 relates to a pusher ship and barge connecting device, and includes a pusher ship having a connecting shaft that can be moved in and out by a cylinder, and a connecting groove into which the tip of the pusher ship is fitted and into which the connecting shaft fits. Barge with is presented.
JP-A-10-10077 JP 2002-331992 A

  Since ancient times, the "Fune", which has a circular planar shape, has been known as a "Tailboat", but it has not been developed and put into practical use as a power ship. The reason for this is that the water line is easy to rotate because it is a circle, and the straight movement is physically difficult. The length-to-width ratio is 1, and the frontal resistance is large as an extremely wide shallow submarine, and the wave resistance is high. The components are large and cannot be industrial products.

  However, the hull form having a length-width ratio of 1 has a minimum surface area as a structure and can have a simple structure. Therefore, it is possible to reduce the materials used, the number of construction steps, and the maintenance cost.

  Recently, a thrust generating device capable of turning 360 degrees has been put into practical use, and its excellent maneuverability and needle-holding property are present as excellent propulsion devices.

  Therefore, a hull under the hexagonal water line inscribed in a circular shape is combined with a rotatable thrust generator, and a hybrid power generation system that is becoming popular as a power source is added. If the state of the ship is improved, it can be developed as a versatile ship with excellent economic efficiency in a small ship that is used at medium and low speeds in plain water.

  Therefore, the present invention improves the increase in resistance at the time of forward / rearward movement, which is a disadvantage of the circular hull form, maintains the stability of the course while maintaining the smooth rotational movement by the strong rudder effect which is an advantage, and minimizes the hull form. We propose a small and medium-sized hull form that rationalizes material and construction costs.

  In addition, since the work ship of the present invention is small and circular and has a thrust generating function at the center of the hull, if it can be easily attached to the rear end of the barge as a separable power section of a large barge, the weak point of the ship of the present invention The seaworthiness performance is improved by integrating with a large barge, and a rational system for barge transportation is possible as an efficient transportation system.

  Barges that do not have a power unit move by being pushed and towed by a pusher ship or a tugboat that sails by itself. Common push / tow methods include wire rope connection and mechanical connection. When a tugboat uses a wire rope to tow a barge, there is a problem that it is difficult to maneuver the barge freely. When towing / pushing by a mechanical device, since the tow / push boat and the barge perform various movements separately, it is difficult to easily connect or disconnect them.

  Accordingly, the present invention proposes a barge that can solve the above-mentioned problems by cooperating with the ship according to any one of claims 1 to 8.

  The ship according to the present invention is configured as follows.

    Claim 1: The upper side outer plate has a cylindrical shape, the lower side outer plate provided below the upper side outer plate has a hexagonal column shape, and a thruster that can be rotated horizontally is provided on the lower side outer plate. A hull centerline connecting opposite ridge angles is set at a symmetrical position on the bottom of the ship with the axis of symmetry as the axis of symmetry.

    [2] The ship according to [1], wherein a duct having a downward opening is provided on the bottom shell plate along the center line of the hull over the entire length of the bottom shell plate.

    (3) In the ship according to (1) or (2), a pillar is provided at the top of the duct at the center of the hull where the lines connecting the opposing ridge angles of the lower outer plate intersect.

    Claim 4: In the ship according to any one of claims 1 to 3, the bottom of the ship is provided with a skeg whose lower end is located below the lower end of the propulsion device.

    Claim 5: In the ship according to any one of claims 1 to 4, a fender is provided around the entire upper end of the upper outer plate.

    Claim 6: The ship according to any one of claims 1 to 5 is provided with a bow-tail ball that also serves as a bow-tail image that can be tilted up and down separately from the main hull.

    Claim 7: In the marine vessel according to any one of claims 1 to 6, a propulsion device with a nozzle that uses the water flow discharged from the pump as a thrust is provided.

    Claim 8: In the ship according to claim 7, the propulsion device is detachably provided in the horizontal direction below the bottom shell plate.

    Furthermore, a U-shaped recess capable of accommodating the ship according to any one of claims 5 to 8 is provided at the stern of the barge.

  An outline will be given of what effects the present invention configured as described above has.

  It is possible to provide a ship having a novel shape with a circular planar shape, and it is possible to turn on the spot by installing a rotatable propulsion device at a symmetrical position (the ship according to claim 1).

  Since the duct is provided at the bottom of the ship, it is possible to reduce the frontal resistance and pitching during forward / rearward travel and to stabilize the course (the ship according to claim 2).

  Since a pillar is provided at the top of the duct at the center of the hull, deck load can be supported and rigidity can be increased. Moreover, an elevator for a small number of people, an electric circuit for lighting, various pipes, a communication cable, and the like can be collected inside the pillar (the ship according to claim 3).

  A skeg whose lower end is located below the lower end of the propulsion device is arranged on the bottom of the ship, and the propulsion device can be protected and the weight of the hull can be supported at the time of lifting (ship of claim 4).

  Since the fenders are provided over the entire circumference of the upper outer plate, it is possible to push the ship to select the place of contact (claim 5).

  The ship according to the present invention has a circular planar shape, and passengers and the like often do not know which direction the stern is. Therefore, a bow-and-tail statue that can be tilted up and down along the floodline is provided separately from the main hull. For example, when it is necessary to inform the crew member of the bow position, the bow-tail image is brought to the bow position and stood up. This bow-tail image is also provided to fulfill the role of the bow-tail ball, so that it is possible to play the role of Barbus Bau when it is tilted under the floodline. That is, the wave resistance can be reduced (a ship according to claim 6).

 Since the jet of the pump is used, it is not necessary to equip the propeller hub with a motor or drive unit connected to the propulsion unit like a propeller type propulsion unit with a mechanical shaft system or an electric drive unit. (The ship according to claim 7).

  Since the jet of the pump is used, there is no need to lay a mechanical mechanism or electrical wiring inside the propulsion unit, and the propulsion unit can be detachably provided from the outside of the bottom plate. This facilitates installation work and maintenance (a ship according to claim 8).

  The barge which concerns on this invention accommodates the ship in any one of Claim 5 thru | or 8 in the recessed part provided in the stern, and sails. That is, the rudder effect is exerted in such a manner that the barge and the tugboat / trawler are in direct contact with each other without being pulled by a wire rope or connected by a mechanical device. Therefore, there is no difficulty in maneuvering as when towing with a wire rope, and difficulty in connection and disconnection as in the case of connection with a mechanical device.

  Hereinafter, more specific effects will be described in detail.

  When the ship of the present invention is used as a sightseeing ship, the course can be accurately maintained and the turn on the spot can be performed freely, so that the planned route can be run while repeating this. In other words, tourists in the cabin can enjoy a 360-degree panoramic view without changing their line of sight.

  When used as a work ship, it is easy to align the center line of the hull with the extension line of the tow line used for towing work, so it is safe and easy to remove the tow line, and the towing device is concentrated at the rear end of the hull. Therefore, the hull length can be shortened, and as a result, the hull form can be easily downsized.

  It is possible to maneuver the same as a dredger equipped with a general Z-type or L-type propulsion shaft or two Voithschneider propulsion units, but it is possible to change the azimuth angle more lightly in the case of a ship with a pivot axis at the center of the hull. In addition, when the hull has a fender all around the hull, it is possible to generate a necessary thrust immediately by contacting the position where the ship is desired, regardless of the place of contact of the ship.

  Furthermore, the work boat can be used in connection with a barge. As shown in FIG. 8, if a U-shaped concave portion 38 is provided in the stern portion of the large barge 37 and the tubular upper side outer plate 9 is fitted and moored via the fender 36, the connecting operation is safe and easy. It becomes certain and it is possible to obtain a greater steering effect. Furthermore, the problem that the ship has, that is, the problem that the length-width ratio is small can be solved. In other words, in the state of being accommodated in the recess of the barge, the length-width ratio including the length of the barge is obtained, so the wave resistance is reduced and the seaworthiness is improved, not only in the harbor but also in the coastal route. Transport is also possible.

  Further, in barge pushing, the work ship according to the present invention has a small circular shape and a thrust generating device in the center of the hull, and has the following unique functions.

  When a pusher that is normally navigating a non-powered mother ship barge tries to maneuver the mother ship barge, both hulls are going to be in the shape of a "<" in the plane (in the case of right turn and vice versa). The mooring device between them needs to withstand that stress. On the other hand, as shown in FIG. 8, the work ship of the present invention has a circular hull built in the rear end of the mother ship barge, so that a moment is generated by directly pushing the rear part of the mother ship barge left and right as a steering force. do not do. Therefore, the mooring device is mainly intended to prevent the work boat from leaving backward, and the device can be simplified.

  In addition, since the work ship according to the present invention is on the water surface surrounded on three sides by the rear part of the mother ship barge, the influence of the wind is reduced and the mooring apparatus as a whole can be reduced.

  Subsequently, since the hull form of the present invention is based on a circular and regular hexagonal geometric plane shape and does not require complicated analog curves, its design and construction are easy.

  In addition, the block division can be easily transported based on the container size, and can be completed by on-site assembly welding.

  Furthermore, when using a jet pump type with a nozzle as a propulsion unit when building or repairing on-site, if the joint 39 is provided in the discharge pipe part directly below the bottom of the ship, the entire apparatus can be moved laterally. Detachable. Therefore, since a large lower space is not required, which is necessary when a propulsion mechanism having a Z-type propulsion shaft or a propulsion mechanism equipped with an electric propulsion mechanism is installed in the housing, repair equipment can be simplified. This produces an effect that is particularly important when using lakesides.

  In addition, by providing a bow / stern ball to increase the length / width ratio of the hull, reduce wave resistance, and when standing up as needed and using it as a stern image, as a character image of the ship It becomes possible to express.

  Hereinafter, as a preferred embodiment, a small passenger ship equipped with a thrust generator, particularly a propulsion device equipped with a discharge flow expanding nozzle will be described, and further supplemented when used as a tugboat (hereinafter referred to as a work ship) used for dredgers and pushers. To do.

  The contents of each figure referred to below are as follows.

  1 is a plan view of the upper deck, FIG. 2 is a plan view of the interior of the hull below the upper deck, FIG. 3 is a vertical cross-sectional view of the hull, FIG. 4 is a cross-sectional view of the same, and FIG. 6 is a plan view of the cockpit deck, FIG. 7 is an external view in the case of a work ship, FIG. 8 is a plan view of the work ship connected to a large barge, and FIG. 9 is another embodiment of the large barge. FIG. 10 is a schematic configuration diagram of the propulsion device in the ship according to claim 7, and FIG. 11 is a schematic side view of the bow-tail image and the bow-tail ball (in FIG. The portion below the line is omitted because it is the same as FIG.

  The hull form of the ship of the present invention is a unique one comprising a circular upper deck, a cylindrical upper outer plate that touches the lower side, and a lower side outer plate that is inscribed in plan view (hexagonal shape) inscribed therein. It is a symmetrical ship shape.

  As shown in FIGS. 1 to 4, if one of the hexagonal ridge angles is positioned as the bow 1, the ridge angle on the opposite side in the longitudinal direction becomes the stern 2 and forms the hull center line 3. The lines connecting the two left and right ridge angles 4 and 4 with the left and right sides respectively form the ship side outer plate parallel part 5, and the horizontal axis 6 connecting the centers thereof is perpendicular to the center point 7 of the vertical axis 3.

  In addition, if the planned inundation line 8 is set on the tortoiseshell type lower side outer plate 10 instead of the cylindrical upper side outer plate 9 having a length / width ratio of “1”, the geometric ratio is approximately “ It becomes 1 to 1.16 ", which is more advantageous than the case where the circular water line surface on the wave resistance is the planned flooding.

  Next, the structure of each part will be described.

  As shown in FIG. 4, a cylindrical upper side outer plate 9 in contact with the circular upper deck 11 extends downward, and a hexagonal column lower side outer plate 10 in contact with it in the upper part of the planned floodline extends further downward. It is fixed to a flat ship bottom skin 12. In that case, the gap between the upper side outer plate 9 and the lower side outer plate 10 is filled with a ship bottom member 13 while forming a chain line, and is fixed to each other to form a hull 14 in the center of the hull.

  Subsequently, in order to reduce the hull resistance when the ship advances according to the present invention, the ship bottom member 13 forms the chineline 15 from the vicinity of the front end and the rear end of the parallel portion 5 of the hull 14 and from above the planned inundation line 8. Upper deck 11 extends toward the bow end and rear end, and in order to reduce resistance when moving forward and backward, the joint between lower side skin 10 and bottom skin 12 is a knuckle line 16 as shown in FIG. 12 and rounded toward the fore and aft, respectively, to reduce the flooded area.

  Further, as shown in FIG. 4, the ship bottom skin 12 is provided with a duct 17 that is open downward along the hull center line 3 and extends over the entire length of the ship skin 12 with the top of the planned floodline 8 as its top surface. It reduces the front resistance and pitching during forward / backward travel, and stabilizes the course.

  Further, as shown in FIG. 4, skegs 18 and 19 are arranged on the bottom of the ship to protect the propulsion device and support the weight of the hull at the time of lifting. The lower ends of the skegs 18 and 19 are provided so as to be positioned below the lower end of the propelling device 23. In addition, it is preferable to attach the small horizontal fin 60 for suppressing a vertical swing to the lower end of the skegs 18 and 19.

  A pillar 20 is provided at the top of the duct 17 at the hull center point 7 to support the deck loads of the upper deck 11 and the upper structure 21.

  Note that a bilge keel 22 is attached to the knuckle line 16 of the hull parallel portion 5 to reduce rolling during normal forward travel and to stabilize the course.

  Now, in the ship according to the present invention, a propulsion device 23 that can rotate 360 degrees as a propulsion device is disposed at a laterally symmetrical position on the outer shaft side on the horizontal shaft 6 to ensure the stability of the course at the time of small steering angle maneuvering, and further to the left and right propulsion. It is possible to quickly obtain a light turning moment in the course by rotating the rudder angle in the forward / reverse direction, or by stopping the single-sided machine, and in narrow waterways where there are restrictions on the course. However, it is possible to perform a complete “spot turn” on the course, which can only be obtained by the hull form and propulsion device, which is capable of complete spot turn with the center of rotation at the center of the hull. It is a unique athletic performance. As the propulsion unit 23, a general-purpose Z-type propulsion shaft, a Voithschneider propulsion unit, or a pod propulsion unit can be used.

  As the propelling device 23, it is more preferable to use the propelling device 23 with a nozzle that expands and uses the water flow discharged from the pump. As shown in FIG. 2, the driving pump 24 of the propelling device 23 with the nozzle is disposed inside a power chamber 26 that is partitioned by a partition wall 25 at the front and rear, and is driven by the power of the power supply device 27 in the same chamber. The apparatus is a generator by a generator prime mover 28 (internal combustion engine), a large-capacity secondary battery, or a combination thereof, and is integrated and installed in the center of the power chamber 26. A sea chest 29 is disposed immediately below the driving pump 24 to shorten the length of the suction pipe and reduce the resistance in the suction pipe. A joint portion 39 made of a flange is provided on the discharge pipe portion 40 directly below the ship bottom, and is fastened with bolts and nuts. Thereby, the propelling device 23 with the nozzle can be easily attached and detached. Further, the discharge pipe 40 is provided with a steering machine 41 capable of turning 360 degrees, and the propulsion unit 23 described in each claim can be turned.

  As shown in FIG. 10, the propelling device 23 with a nozzle discharges seawater sucked from a sea chest 29 through a discharge pipe 40 to a bell-shaped nozzle 42 with an outer cylinder expanding and rectifying the water flow. is there. Inside the nozzle 42, a ring 43 having an airfoil cross section as an inner cylinder is fixed through a rectifying plate 45 together with a shell-type cone 44 positioned on the center line. The inside of the cone 44 is hollow and the bottom surface is open. The ring 43 and the cone 44 are fixed to each other by a rectifying plate 45. The spindle-shaped half-shaped housing 46 is for the purpose of adjusting the water flow outside the bell-shaped nozzle 42 and the discharge pipe 40 used as a rudder shaft.

 In the pillar 20 extending from the center point 7 in the power chamber 26 into the upper structure 21, work elevators, lighting circuits, various pipes, communication cables, and the like are collected and installed around the pillar 20 in the power chamber 26. Installed in each device.

  1 to 6, the upper deck directly above the power chamber 26 is provided with a required maintenance opening 30 and its surrounding wall, an entrance / exit room, a crew room, a deck warehouse, and the like. The cabin deck 31 directly above the deck room is provided with cabins and related facilities, the upper part is a cockpit deck 32, the ship handling chambers 33 are gathered together and the mast 35 is installed on the top deck 34. .

  The outer shape of the deck room on each of the above decks is all tortoiseshell shaped, so that the common recognition that one of the ridges is the bow is necessary for passengers and passengers to ensure safety such as emergency guidance It is a response. Therefore, in addition to the above, for example, it is also effective to attach a bow-tail image or the like to the bow-end ridge corner.

  Therefore, in the following, a detailed description will be given of the case of controlling the wave resistance of a wide shallow submerged ship type like a ship according to the present invention by providing a bow image as shown in FIG.

7 and 11, 47 is a bow image, and in this case, it is provided in a shape that assumes the head of a marine mammal such as “ka”. In the present invention, the bow image 47 is provided not to be simply fixed to the bow, but also to be tilted up and down so as to protrude on the center line larger than the tip of the bow edge ridge angle. That is, a steel ball 49 is embedded in the horizontal support fin 48 fixed over both side walls of the duct 17, and a spherical groove provided at the lower end of the bow image 47 is loosely fitted to the steel ball 49. Yes. By tilting downward with the steel ball 49 as the center, the bow image 47 can be positioned almost horizontally below the floodline 8. On the other hand, the bow image 47 can be moved to the retracted position by raising the steel ball 49 as the center.
This raising / lowering operation is performed by guiding a wire 51 to a small eye plate 50 attached in front of the top of the bow image 47 and pulling the wire 51 by a small winch 53 attached to the front surface of the deck room 52. Thus, in the present invention, the bow image 47 is given a function as a bow ball (hereinafter referred to as a bow ball).
Fin-type stopper fins 59 are provided on both sides of the bow image (bow ball) 47. This is to suppress the horizontal movement of the bow ball 47.

  The upper deck 11 is similarly cut into a U shape, and a surrounding wall 54 is provided around the upper deck 11 so that the space between the upper deck 11 and the duct top surface 17a is watertight. The bulwark 55 is also cut so as to allow the bow image 47 to rotate, and further, a U-shape is recessed on the outer side of the image as shown in FIG. The fender 36 is also opened as shown in FIG. 1 so that the image 47 can be rotated and tilted.

  The bow 47 is made of an elastic body such as synthetic rubber, and is characterized in that the impact of waves received as the bow 47 is not given to the eye plate 48, the wire 51, and the winch 53. The winch 53 detects the tension of the wire 51. At the same time, the swing of the pole 47a at the tip of the bow ball 47 is observed, and the trim of the bow ball 47 itself can be adjusted so that an excessive load is not generated. This bow figure 47 can be chosen freely from those with various PR images as passenger ships in the area, and the PR effect will be even greater if the shape of the streamline required as the bow ball 47 is made under the surface of the water. It is assumed that Furthermore, as shown in Fig. 3, if the tail of an aquatic creature is used as the stern image corresponding to the bow image as necessary, the stern ball can improve the maintenance of the needle and the turbulence of the water flow at the rear end of the hull. The PR effect is further increased as the resistance is reduced and the energy saving effect is increased.

  The above apparatus can also be applied to the case of a work ship (a dredger). That is, when cruising, the bow ball 47 is lowered to a predetermined position in the water shown in FIG. 7 for energy-saving navigation, and when pushing up, it can be turned to the position shown in FIG. In this case, since the bow ball 47 is formed of an elastic body, it does not damage the ship side skin of the ship. Moreover, it is easy to give the bow ball 47 enough flexibility to cope with the flare of the outer plate of the ship. This performance makes it possible to avoid damage caused by the contact between the ship and the ship even in the event of a collision during cruising.

  Subsequently, when the ship according to the present invention is used as a work ship, as shown in FIGS. 7 and 8, each deck overhanging portion (eave portion 56) is removed to form a tower-shaped upper structure as shown in FIG. Thus, the work on the upper deck 11 from the cockpit deck 32 can be directly viewed. Also in this case, if each deck is formed as a turtle shell type, it is easy to grasp the bow-stern direction, that is, the bow-stern direction of the hull centerline 3 when viewing the accompanying work vessel of the present invention from the large crushed ship. . In addition, when viewing from the side of the other ship, it can be distinguished from regular use with a little stern trim and the shape of bulwark, mast, etc. It can be confirmed from the position of the ship name, the registered port name, etc., and the discrimination before and after can be handled in the same way as a normal ship, so there is no problem in the operational safety of this ship type.

  The apparent weight of the stern ball 7 in the water has an internal structure in which the buoyancy of the sphere is slightly smaller than the amount of drainage due to the water flow flowing from the air vent hole 57 and the hydrophobic hole 58 at the front end and the rear end, and restrains the floating of the sphere during navigation. It is assumed that the water is automatically drained from the hydrophobic hole 58 when standing upright.

  As shown in FIG. 8, the barge according to the present invention is provided with a recess 38 by cutting out the stern 37 a of the large barge 37. Further, as shown in FIG. 9, if a temporary connecting jig 38 a having a concave shape is installed at the stern of the large barge 37 instead of the recess 38, a general-purpose trapezoidal large barge can be used as a connecting barge. It becomes possible.

Upper deck plan view. The upper deck lower hull internal top view. FIG. FIG. Deck room cabin deck top view. The cockpit deck plan view. The external view in the case of a work ship. The top view at the time of connecting with a large barge as a work ship. The top view which showed the other Example of the large sized barge. The partial fracture | rupture schematic block diagram of a propulsion device. A side view of a bow figure (bow ball).

Explanation of symbols

3. Hull center line 7 Hull center point 9 Upper skin 10 Lower skin 12 Bottom skin 17 Duct 18, 19 Skeg 20 Pillar 23・ 36 ・ ・ Nailproof material 37 ・ ・ Barge 38 ・ ・ Recess 47 ・ ・ Stern ball

Claims (8)

  The upper side outer plate 9 has a cylindrical shape, the lower side outer plate 10 provided below the upper side outer plate 9 has a hexagonal column shape, and the thruster 23 that can be rotated in the horizontal direction is connected to the lower side outer plate 10. A ship provided at a symmetrical position on the bottom of the ship, with the hull center line 3 connecting the opposite ridge angles as the axis of symmetry.   The ship according to claim 1, wherein a lower open-type duct 17 having a top plate near the inundation line along the hull center line 3 is provided in the ship bottom skin 12 over the entire length of the ship bottom skin 12.   The ship according to claim 2, wherein a pillar 20 is provided at the top of the duct 17 at the hull center point 7 where the lines connecting the opposite ridge angles of the lower side outer plate 10 intersect.   The ship according to any one of claims 1 to 3, wherein the bottom of the ship is provided with skegs (18, 19) whose lower end is located below the lower end of the propeller.   The ship according to any one of claims 1 to 4, wherein a fender is provided over the entire upper end of the upper side outer plate.   The ship according to any one of claims 1 to 5, further comprising a bow-tail ball 47 that also serves as a bow-tail image that is installed upside down on the waterline separately from the main hull.   The marine vessel according to any one of claims 1 to 6, wherein the propulsion unit 23 is a propulsion unit with a nozzle that uses a water flow discharged from a pump as a thrust.   The marine vessel according to claim 7, wherein the nozzle-equipped propulsion device 23 is detachable.

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