A rescue unmanned surface vessel capable of carrying amphibious drones

Abstract

This invention discloses a rescue unmanned surface vessel (USV) capable of carrying amphibious drones, comprising: a hull, a rescue container, and an onboard platform. The hull includes: a waterproof gimbal camera, a searchlight, a GPS antenna, a cooling fan, an underwater motor, hull mounting posts, a hatch cover, and a rudder mechanism. The rescue container includes: a side door, a side door switch, a bottom door, and a life-saving device. In cases of multiple drownings, the rescue capability of a single amphibious drone is limited. This invention allows multiple amphibious drones to be deployed for rescue. After rescuing one person, the amphibious drone can tow the person to the vicinity of the rescue USV, at which point the rescue container releases the life-saving device, allowing the amphibious drone to continue rescuing the next person. This improves overall rescue efficiency and avoids missing the optimal rescue time.

Description

Technical Field

[0001] This invention relates to the field of unmanned vessel technology, and in particular to a rescue unmanned vessel capable of carrying amphibious drones. Background Technology

[0002] With the rapid development of science and technology, my country's development of waterways and sea areas is increasing, which has also promoted the development of unmanned surface vessels (USVs) and related technologies. The main function of USVs is surface cruising, possessing advantages such as strong payload capacity, continuous operation, and long endurance, enabling them to perform missions far from the coast. However, with increasing human activity on water, drowning accidents frequently occur. Currently, various rescue USVs are used in the rescue field. Patent No. 201921252749.X proposes a surface rescue boat that can be remotely controlled to reach the person being rescued; however, this surface rescue boat has a relatively slow speed, and if it is too far from the person being rescued, the optimal rescue time may be missed. Currently, various amphibious rescue drones can also carry out rescues, but their payload capacity is limited, generally only able to rescue one person at a time; if multiple people need rescue, there is a waiting period after rescuing the first person before the second person can be rescued, thus reducing the efficiency of subsequent rescues. Patent No. 202110045901.2 discloses an amphibious rescue stretcher that can quickly fly to the vicinity of the person being rescued, land on the water, and then navigate on the water to provide buoyancy to the person being rescued, before bringing them to shore. However, when rescuing multiple people, a considerable waiting time is required before rescuing the next person. To reduce the impact of the underwater motors on the flight of the amphibious drone, the size and weight of the underwater motors cannot be too large, thus limiting the power for surface navigation.

[0003] Existing rescue unmanned surface vessels (USVs) suffer from several drawbacks. Limited sensor variety leads to inaccurate positioning; even fewer can carry amphibious drones for joint rescue operations; and few are suitable for the continuous, rapid rescue of multiple people. Furthermore, when a USV approaches a person being rescued, it can be difficult for those who have been waiting for a long time to grasp the life-saving devices on the hull. All these factors contribute to the poor effectiveness of USV rescue operations. Summary of the Invention

[0004] To overcome the shortcomings of the existing technology, the present invention provides the following technical solution: a rescue unmanned surface vessel capable of carrying an amphibious drone, comprising: a hull, a rescue box, and an airborne platform. The hull includes: a waterproof gimbal camera, a searchlight, a GPS antenna, a cooling fan, an underwater motor, hull mounting posts, a hatch cover, a rotary servo, a connecting platform, and a loudspeaker. A waterproof gimbal camera is mounted on the upper surface of the foremost end of the hull. A searchlight and a GPS antenna are mounted on the upper surface of the foremost end of the hull. Underwater motors are mounted on both sides of the lower rear end of the hull. A cooling fan is mounted on the upper surface of the rear end of the hull. The lower part of the column is installed inside the hull. The middle and upper parts of the hull mounting column are used to fix and install the hatch cover and the airborne platform. The hatch cover is installed on the upper surface of the hull. Rotary servo motors, connecting platforms, rescue boxes and loudspeakers are installed on both sides of the upper surface of the hull. A circular rotating plate is installed on the protruding shaft of the rotary servo motor. One side of the rotating plate is installed on the protruding shaft of the rotary servo motor and the other side is connected to the servo motor connecting rod. One end of the servo motor connecting rod is connected to the rotating plate and the other end is connected to the fixing hole. The hull is equipped with a controller, an airborne computer, an underwater motor ESC, a GPS module, a signal receiver and a power module.

[0005] The rescue box includes: a side door, a side door switch, a bottom door, a rescue device, an internal servo motor, and an internal rotating baffle. The side door is installed on the side of the rescue box, the side door switch is installed on the side door, the bottom door is installed on the bottom surface of the rescue box, and a bottom door baffle is installed on the upper surface of the bottom door. The rescue device is placed inside the rescue box, the internal servo motor is installed inside the rescue box, and the protruding shaft of the internal servo motor is connected to one end of the internal rotating baffle.

[0006] The airborne platform includes: a connecting rod, a float, a limiting frame, and a gripper position. One end of the connecting rod is connected to the connecting platform and the other end is connected to the float. A fixing hole is installed at the rear of the end of the connecting rod connected to the connecting platform. The limiting frame is on the upper surface of the airborne platform, and the gripper positions are on both sides of the airborne platform. The limiting frame has a fixing hole.

[0007] Preferably, the controller controls the underwater motor via an underwater motor ESC, and controls the rotation of the rotary servo and the servo inside the housing. The signal receiver can receive and transmit signals from the remote control. The onboard computer can be deployed to perform relevant image recognition calculations and path planning algorithms, preprocess the surrounding environment, and assist remote operators in rescue operations.

[0008] Preferably, there are at least three connecting platforms on each side of the hull, and each connecting platform has a cylindrical connecting shaft in the middle, with the connecting shaft of the connecting platform connected to one end of the connecting rod; the connecting platform installed at the foremost or rearmost end has a notch on one side, and these notches allow the servo linkage to pass through.

[0009] Preferably, two rotary servos are installed on each side of the upper surface of the hull; the axes of the protruding shaft, rotating plate, and connecting shaft in the middle of the connecting platform of each rotary servo are collinear, and the collinear direction is parallel to the longitudinal centerline of the hull. The rotation of the protruding shaft of the rotary servo drives the rotating plate to rotate, the rotating plate drives the servo linkage, and finally drives the connecting rod to rotate.

[0010] Preferably, the rescue boxes are installed on both sides of the upper surface of the hull, with at least two rescue boxes installed on each side of the hull; the protruding shaft of the internal steering gear inside the rescue box rotates, which in turn drives the rotating baffle inside the box to rotate. The rescue box can also be opened or closed by turning the side door switch on the side door of the rescue box.

[0011] Preferably, the float is made of rigid plastic with a through-hole hollow cavity, and the density of the rigid plastic ranges from 0.8 to 1.5 g / cm³. The float has two states: raised and lowered. When the float is raised, it is located on both sides of the airborne platform, and the lower surface of the float is coplanar with the lower surface of the airborne platform. When the float is lowered, it moves away from both sides of the airborne platform and is located below both sides of the airborne platform, with the lower surface of the float above the water surface.

[0012] Preferably, the connecting rod has an "L" shape, with both ends connected in a circular ring shape.

[0013] Preferably, the central axis of the cooling channel of the cooling fan forms an angle of 30° to 60° with the horizontal plane, and the channel outlet faces downward at the rear of the hull to prevent water from entering the cabin.

[0014] Preferably, the life-saving device is a rescue device that can quickly and automatically inflate into an airbag when it falls into the water.

[0015] Preferably, the amphibious drone is placed within the limiting frame of the airborne platform; this prevents the amphibious drone from sliding freely on the airborne platform when the ship moves. The upper surface of the airborne platform is higher than the upper surface of the front-end devices such as searchlights and GPS antennas.

[0016] Compared with the prior art, the beneficial effects of the present invention are:

[0017] (1) The rescue unmanned vessel can use a powerful underwater motor, which makes the surface navigation power of the rescue unmanned vessel generally greater than that of the amphibious drone, and the buoyancy on the water surface is also much greater than that of a single amphibious drone; the rescue unmanned vessel has a dual-antenna GPS device at the front, which makes the positioning more accurate; there is a waterproof gimbal camera at the front, which provides a wide field of view; there is a searchlight at the front of the hull, which can carry out normal operations even at night.

[0018] (2) The rescue unmanned boat can carry multiple amphibious drones for rescue. After the amphibious drones rescue a person, they can drag the person to the vicinity of the boat so that the rescued person can hold onto the boat, while the amphibious drones continue to rescue the next person, thus improving the overall rescue efficiency.

[0019] (3) Unmanned boats can carry multiple life-saving devices and can rescue multiple drowning people at the same time; when they cooperate with amphibious drones for rescue, they can make up for the shortcoming that amphibious rescue drones can only rescue one person at a time.

[0020] (4) The ship is equipped with an onboard computer that can deploy relevant algorithms and assist in rescue operations; the ship has a large internal space that can accommodate a large-capacity power supply, thus increasing its endurance; the rescue unmanned ship has a large internal space that can accommodate more and larger capacity batteries, thus increasing its endurance. Attached Figure Description

[0021] Figure 1 This is a three-dimensional view of the overall structure of the present invention.

[0022] Figure 2 This is an axial view of the overall structure of the present invention.

[0023] Figure 3 This is a top view of the overall structure of the present invention.

[0024] Figure 4 This is a bottom view of the overall structure of the present invention.

[0025] Figure 5 This is a front view of the overall structure of the present invention.

[0026] Figure 6 This is a rear view of the overall structure of the present invention.

[0027] Figure 7 This is a side view of the overall structure of the present invention.

[0028] Figure 8 The overall structure of this invention is shown in the axial view without the airborne platform.

[0029] Figure 9 The top view of the overall structure of the present invention is shown without the airborne platform.

[0030] Figure 10The image shows the overall structure of the invention without the airborne platform and the ship's hatch cover.

[0031] Figure 11 This is a top view of the overall structure of the invention without the airborne platform and the ship's hatch cover.

[0032] Figure 12 This is a schematic diagram of the invention carrying two amphibious drones.

[0033] Figure 13 This is an axial view of the lowering of the float in the overall structure of the present invention.

[0034] Figure 14 For the present invention Figure 8 The top view of the enlarged schematic diagram at point A in the middle.

[0035] Figure 15 For the present invention Figure 8 Axial view of a partially enlarged schematic diagram at point A in the middle.

[0036] Figure 16 For the present invention Figure 7 A magnified view of the side door of the rescue box opened at point B.

[0037] Figure 17 For the present invention Figure 7 A magnified view of the side door of the rescue box being opened and the life-saving device being placed at point B.

[0038] Figure 18 This is a top sectional view of the rescue box of the present invention.

[0039] Figure 19 This is a side sectional view of the rescue box of the present invention.

[0040] Figure 20 This is a side cross-sectional view of the cooling fan of the present invention.

[0041] Explanation of reference numerals in the attached drawings: 1. Hull; 101. Waterproof gimbal camera; 102. Searchlight; 103. GPS antenna; 104. Cooling fan; 105. Underwater motor; 106. Hull mounting post; 107. Cabin cover; 108. Controller; 109. Onboard computer; 111. Rotary servo; 112. Connecting platform; 113. Loudspeaker; 114. Servo linkage; 1141. Rotary vane; 115. Underwater motor ESC; 116. G PS module; 117, signal receiver; 118, power module; 2, rescue box; 201, rescue box side door; 202, side door switch; 203, rescue box bottom door; 2031, bottom door baffle; 204, life-saving device; 205, internal servo motor; 206, internal rotating baffle; 3, airborne platform; 301, connecting rod; 3011, fixing hole; 302, float; 303, limit frame; 304, gripper position; 305, fixed mounting hole. Detailed Implementation

[0042] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0043] Please see Figures 1 to 20 This invention provides a technical solution: a rescue unmanned surface vessel capable of carrying amphibious drones, comprising: a hull 1, a rescue box 2, and an onboard platform 3. The hull 1 includes: a waterproof gimbal camera 101, a searchlight 102, a GPS antenna 103, a cooling fan 104, an underwater motor 105, hull mounting posts 106, a cabin cover 107, a rotary servo motor 111, a connecting platform 112, and a loudspeaker 113. The waterproof gimbal camera 101 is mounted on the upper surface of the foremost end of the hull 1. The searchlight 102 and the GPS antenna 103 are mounted on the upper surface of the foremost end of the hull 1. The underwater motors 105 are mounted on both sides of the lower rear end of the hull 1. The cooling fan 104 is mounted on the upper surface of the rear end of the hull 1. The lower part of the hull mounting posts 106 is installed inside the hull 1. The middle and upper parts of the hull mounting column 106 are used to fix and install the hatch cover 107 and the airborne platform 3. The hatch cover 107 is installed on the upper surface of the hull 1. Rotary servo motor 111, connecting platform 112, rescue box 2 and loudspeaker 113 are installed on both sides of the upper surface of the hull 1. A circular rotating plate 1141 is installed on the protruding shaft of the rotary servo motor 111. One side of the rotating plate 1141 is installed on the protruding shaft of the rotary servo motor 111 and the other side is connected to the servo motor connecting rod 114. One end of the servo motor connecting rod 114 is connected to the rotating plate 1141 and the other end is connected to the fixing hole 3011. The hull 1 is equipped with a controller 108, an airborne computer 109, an underwater motor ESC 115, a GPS module 116, a signal receiver 117 and a power module 118.

[0044] The rescue box 2 includes: a rescue box side door 201, a side door switch 202, a rescue box bottom door 203, a rescue device 204, an internal servo motor 205, and an internal rotating baffle 206. The rescue box side door 201 is installed on the side of the rescue box 2, the side door switch 202 is installed on the rescue box side door 201, the rescue box bottom door 203 is installed on the lower surface of the rescue box 2, and a bottom door baffle 2031 is installed on the upper surface of the rescue box bottom door 203. The rescue device 204 is placed inside the rescue box 2, the internal servo motor 205 is installed inside the rescue box 2, and the protruding shaft of the internal servo motor 205 is connected to one end of the internal rotating baffle 206.

[0045] The airborne platform 3 includes: a connecting rod 301, a float 302, a limiting frame 303, and a gripper position 304. One end of the connecting rod 301 is connected to the connecting platform 112 and the other end is connected to the float 302. A fixing hole 3011 is installed at the rear of the end of the connecting rod 301 connected to the connecting platform 112. The limiting frame 303 is on the upper surface of the airborne platform 3. The gripper positions 304 are on both sides of the airborne platform 3. The limiting frame 303 has a fixing installation hole 305. The upper part of the hull mounting column 106 is installed in the fixing installation hole 305.

[0046] like Figure 10 and 11 As shown, the GPS antenna 103 mounted at the front of the rescue drone and the internal GPS module 116 enable high-precision positioning, ensuring the reliability of the navigation route. The drone's controller 108 controls the underwater motor 105 via an underwater motor ESC 115. The controller 108 also controls the rotation of the rotary servo motor 111 and the internal servo motor 205. The signal receiver 117 can receive and transmit signals from the remote control. The onboard computer 109 can deploy relevant image recognition calculations and path planning algorithms to preprocess the surrounding environment, assisting remote operators in rescue operations. The hull 1 has a large internal space, allowing for the placement of a large-capacity power module 118, increasing the boat's endurance. Figure 20 As shown, the central axis of the heat dissipation channel of the cooling fan 104 forms an angle of 30° to 60° with the horizontal plane, and the channel outlet faces downward at the rear end of the hull 1 to prevent water from entering the cabin.

[0047] There are at least three connecting platforms 112 on each side of the hull 1, which makes the connection between the connecting platforms 112 and the floats 302 via the connecting rods 301 more stable. Each connecting platform 112 has a cylindrical connecting shaft in the middle, and the connecting shaft of the connecting platform 112 is connected to one end of the connecting rod 301. The connecting platforms 112 installed at the foremost or rearmost end have notches on one side, and these notches allow the servo linkage 114 to pass through. At the same time, these notches restrict the range of movement of the servo linkage 114, and thus also restrict the range of movement of the connecting rods 301 and the floats 302.

[0048] like Figure 14 and 15 As shown, two rotary servo motors 111 are installed on each side of the upper surface of the hull 1; the axes of the protruding shaft, rotating plate 1141, and connecting shaft of the connecting platform 112 of each rotary servo motor 111 are collinear, and the collinear direction is parallel to the longitudinal centerline of the hull 1. The rotation of the protruding shaft of the rotary servo motor 111 drives the rotating plate 1141 to rotate, the rotating plate 1141 drives the servo linkage 114, and finally drives the connecting rod 301 to rotate.

[0049] The float 302 is made of rigid plastic with a through-hole hollow cavity, such as polycarbonate (PC), polystyrene (PS), or polyoxymethylene (POM). The float 302 has two states: raised and lowered. When raised, the float 302 is located on both sides of the airborne platform 3, and its lower surface is coplanar with the lower surface of the airborne platform 3. Figure 13 As shown, when the float 302 descends, it moves away from both sides of the airborne platform 3, and its lower surface is above the water. Once the boat reaches the person being rescued, they can hold onto the float 302 and the grab handles 304 on the airborne platform 3. The connecting rod 301 has an "L" shape, with circular joints at both ends, connecting the connecting platform 112 and the float 302 respectively.

[0050] like Figures 16 to 19 As shown, rescue boxes 2 are installed on both sides of the upper surface of the hull 1, with at least two rescue boxes 2 installed on each side of the hull 1. The protruding shaft of the internal steering gear 205 inside the rescue box 2 rotates, causing the internal rotating baffle 206 to rotate as well, thereby controlling the opening and closing of the lower door 302 of the rescue box. After the lower door 302 of the rescue box is opened, the life-saving device 204 will automatically fall out of the rescue box 2 under its own weight. By turning the side door switch 202 on the side door 201 of the rescue box, the side door 201 of the rescue box can be opened or closed, and then the life-saving device 204 can be placed or removed. The life-saving device 204 is a rescue device that automatically inflates into an airbag upon entering the water.

[0051] An amphibious drone is placed within the limiting frame 303 of the airborne platform 3; this prevents the amphibious drone from sliding freely on the airborne platform when the ship moves. The upper surface of the airborne platform 3 is higher than the upper surfaces of front-end devices such as the searchlight 102 and GPS antenna 103. Figure 12 As shown, two amphibious drones are typically placed on the upper surface of the airborne platform 3. If the area of ​​the airborne platform 3 is increased, more amphibious drones can be placed there.

[0052] Rescue Procedure: When the rescue unmanned vessel is patrolling the water, its onboard platform 3 typically carries two fully charged amphibious drones in standby mode. Upon receiving information about someone drowning, the rescue unmanned vessel immediately stops its navigation and initiates takeoff of the amphibious drones, flying towards the area requiring rescue. If the number of people requiring rescue is no more than two, only the amphibious drones need to be deployed; if more than two people require rescue, after the amphibious drones take off in sequence, the rescue unmanned vessel will proceed to the area where the nearest amphibious drone will land for the rescue. After the rescue drone arrives at the rescue area, the remote controller operates the rotary servo 111 to lower the float 302. The person being rescued then grabs the float 302 or the grab handle 304 while simultaneously releasing the amphibious drone. The remote controller then operates the internal servo 205 of the rescue box 2, which rotates the internal rotating baffle 206, opening the lower door 203 of the rescue box. The life-saving device 204 will then drop onto the water and inflate into an airbag, which the person being rescued can hold onto while awaiting further rescue. If the internal servo 205 malfunctions or other issues prevent the lower door 203 from opening properly, the person being rescued can manually rotate the side door switch 202 while still holding the float 302 or grab handle 304 to open the side door 201 and retrieve the life-saving device 204. Meanwhile, personnel operating the rescue drone on the shore can use a loudspeaker to call out to or guide those being rescued.

[0053] To improve rescue efficiency, when a rescue drone is heading to a waterway where an amphibious drone is landing, if the amphibious drone is close to the shore, the rescue drone may not need to go there; the amphibious drone can directly bring the rescued person to shore. After completing all rescue missions, the batteries in both the amphibious drone and the rescue drone should be replaced promptly. The amphibious drone should be dried before being placed on the rescue drone.

[0054] The above-described embodiments are only used to illustrate the preferred technical solutions of this application, and are not intended to limit it. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A rescue unmanned surface vessel capable of carrying amphibious drones, characterized in that, include: The ship comprises a hull (1), a rescue box (2), and an airborne platform (3). The hull (1) includes: a waterproof gimbal camera (101), a searchlight (102), a GPS antenna (103), a cooling fan (104), an underwater motor (105), a hull mounting column (106), a hatch cover (107), a rotary rudder (111), a connecting platform (112), and a loudspeaker (113). The waterproof gimbal camera (101) is mounted on the upper surface of the foremost end of the hull (1). The foremost end of the hull (1) is... The upper surface of the hull (1) is equipped with a searchlight (102) and a GPS antenna (103). Underwater motors (105) are installed on both sides of the lower rear end of the hull (1). A cooling fan (104) is installed on the upper surface of the rear end of the hull (1). The lower part of the hull mounting column (106) is installed inside the hull (1). The middle and upper parts of the hull mounting column (106) are used to fix and install the hatch cover (107) and the airborne platform (3). The hatch cover (107) is installed on the upper surface of the hull (1). On the upper surface of the hull (1), a rotary rudder (111), a connecting platform (112), a rescue box (2), and a loudspeaker (113) are installed on both sides. A circular rotating plate (1141) is installed on the protruding shaft of the rotary rudder (111). One side of the rotating plate (1141) is installed on the protruding shaft of the rotary rudder (111), and the other side is connected to the rudder linkage (114). One end of the rudder linkage (114) is connected to the rotating plate (1141), and the other end is connected to the fixing hole (3011). The hull (1) is equipped with a controller (108), an onboard computer (109), an underwater motor ESC (115), a GPS module (116), a signal receiver (117), and a power module (118); two rotary servos (111) are installed on each side of the upper surface of the hull (1); the axes of the protruding shaft, the rotating plate (1141), and the connecting shaft in the middle of the connecting platform (112) of each rotary servo (111) are collinear, and the collinear direction is parallel to the longitudinal centerline of the hull (1); The rescue box (2) includes: a rescue box side door (201), a side door switch (202), a rescue box bottom door (203), a rescue device (204), an internal servo motor (205), and an internal rotating baffle (206). The rescue box side door (201) is installed on the side of the rescue box (2), the side door switch (202) is installed on the rescue box side door (201), the rescue box bottom door (203) is installed on the lower surface of the rescue box (2), and a bottom door baffle (2031) is installed on the upper surface of the rescue box bottom door (203). The rescue device (204) is placed inside the rescue box (2), and the internal servo motor (205) is installed inside the rescue box (2). The protruding shaft of the internal servo motor (205) is connected to one end of the internal rotating baffle (206). The airborne platform (3) includes: a connecting rod (301), a float (302), a limiting frame (303), and a gripper position (304). One end of the connecting rod (301) is connected to the connecting platform (112), and the other end is connected to the float (302). A fixing hole (3011) is installed at the rear of the end of the connecting rod (301) connected to the connecting platform (112). The limiting frame (303) is on the upper surface of the airborne platform (3), and the gripper position (304) is on both sides of the airborne platform (3). The limiting frame (303) has a fixing installation hole (305), and the upper part of the hull mounting column (106) is installed in the fixing installation hole (305).

2. A rescue unmanned surface vessel capable of carrying amphibious drones according to claim 1, characterized in that: The connecting platform (112) has a cylindrical connecting shaft in the middle, and the connecting shaft of the connecting platform (112) is connected to one end of the connecting rod (301).

3. A rescue unmanned surface vessel capable of carrying amphibious drones according to claim 1, characterized in that: The protruding shaft of the servo motor (205) inside the rescue box (2) rotates, which can drive the rotating baffle (206) inside the box to rotate; the rescue box (2) can be opened or closed by manually rotating the side door switch (202) on the side door (201) of the rescue box.

4. A rescue unmanned surface vessel capable of carrying amphibious drones according to claim 1, characterized in that: The float (302) is made of rigid plastic with a through hollow cavity inside, and the density of the rigid plastic ranges from 0.8 to 1.5 g / cm³. The float (302) has two states: raised and lowered. When the float (302) is raised, the lower surface of the float (302) and the lower surface of the airborne platform (3) are coplanar.

5. A rescue unmanned surface vessel capable of carrying an amphibious drone according to claim 1, characterized in that: The central axis of the cooling channel of the cooling fan (104) is at an angle of 30° to 60° with the horizontal plane, and the channel outlet faces downwards at the rear end of the hull (1).

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