Foldable hydrofoil boat

Abstract

The present invention provides a foldable hydrofoil boat, belonging to the technical field of boats, comprising a boat body, at least one hydrofoil propulsion mechanism connected to the boat body; the hydrofoil propulsion mechanism comprises a support frame, a folding arm assembly, a driving assembly and a hydrofoil propulsion assembly; the support frame is arranged on the boat body; the hydrofoil propulsion assemblies are arranged on both sides of the boat body, and the hydrofoil propulsion assemblies are movably connected to the support frame through the folding arm assembly; the driving assembly is movably connected to the support frame and the folding arm assembly, respectively, for adjusting the unfolding angle of the folding arm assembly relative to the horizontal plane; the unfolding angle of the folding arm assembly relative to the horizontal plane is adjusted by the driving assembly, and then the angle of the hydrofoil propulsion assembly relative to the horizontal plane is adjusted to ensure the stability and safety of driving. The foldable hydrofoil boat of the present application can be driven in relatively severe sea conditions and weather, and can be widely used in military, fishing, rescue, entertainment, transportation and other fields.

Description

Technical Field

[0001] The invention relates to the technical field of boats and ships, and in particular to a foldable hydrofoil boat. Background Art

[0002] The hydrofoil boat is a new type of high-performance ship with good wave resistance and low sailing resistance. The principle is that in a fluid, the greater the flow velocity, the lower the pressure. When the hydrofoil boat is sailing in the water at high speed, the upper surface of the hydrofoil of the hydrofoil is convex, the water flow velocity between the hydrofoil and the hull is high and the pressure is low, while the water flow velocity on the lower surface is low and the pressure is high. Therefore, there is an upward pressure difference between the upper and lower surfaces of the hydrofoil. When sailing, the dynamic lift of the hydrofoil boat bears part of the static water buoyancy, the hull is lifted, and the displacement volume and wet surface area of ​​the hydrofoil boat are reduced.

[0003] When a hydrofoil boat is sailing, the contact depth between its hull and the water surface is small, its self-stability is poor, and its rolling is more severe, which has an adverse effect on the seaworthiness and safety of the hydrofoil boat. Summary of the invention

[0004] The purpose of the present invention is to provide a foldable hydrofoil boat, which can adjust the unfolding angle of the folding arm assembly relative to the horizontal plane during travel, and then adjust the angle of the hydrofoil propulsion assembly relative to the horizontal plane to ensure the stability and safety of travel.

[0005] Based on the above purpose, the foldable hydrofoil boat provided by the present invention comprises:

[0006] A hull, at least one hydrofoil propulsion mechanism connected to the hull;

[0007] The hydrofoil propulsion mechanism comprises a support frame, a folding arm assembly, a driving assembly and a hydrofoil propulsion assembly;

[0008] The support frame is arranged on the hull;

[0009] The hydrofoil propulsion assemblies are respectively arranged on both sides of the hull, and the hydrofoil propulsion assemblies are movably connected to the support frame through a folding arm assembly;

[0010] The driving assembly is movably connected to the supporting frame and the folding arm assembly respectively, and is used to adjust the unfolding angle of the folding arm assembly relative to the horizontal plane.

[0011] Furthermore, one hydrofoil propulsion mechanism is provided and located at one end of the length direction of the hull, and an auxiliary hydrofoil propulsion assembly is connected to the bottom of the hull, and the auxiliary hydrofoil propulsion assembly is located at the other end of the length direction of the hull.

[0012] Furthermore, two hydrofoil propulsion mechanisms are provided and are arranged respectively at a position close to the bow and a position close to the stern.

[0013] Further, the hydrofoil propulsion assembly includes a first connecting rod, a first hydrofoil and a first propeller;

[0014] The first connecting rod is movably connected to the folding arm assembly;

[0015] The first hydrofoil is connected to the bottom end of the first connecting rod;

[0016] The first propeller is connected to the bottom end of the first hydrofoil.

[0017] Further, the folding arm assembly includes an upper support arm and a lower support arm;

[0018] The upper support arm is movably connected to the support frame and the hydrofoil propulsion assembly respectively;

[0019] The lower support arm is movably connected to the support frame and the hydrofoil propulsion assembly respectively.

[0020] Furthermore, the support frame includes a first support frame in an inverted U shape and at least two transverse supports arranged from top to bottom;

[0021] The first bracket includes vertical rods fixed on both sides of the hull and arc rods connected between the vertical rods, the arc rods are upwardly protruding, the transverse bracket is connected between the vertical rods, and the transverse bracket is movably connected to the corresponding upper support arm and lower support arm through an axis.

[0022] Furthermore, a limiting groove is provided at one end of the upper support arm and the lower support arm close to the vertical rod, so that the vertical rod can be inserted into the limiting groove, and the arc rod can be inserted into the limiting groove of the upper support arm.

[0023] Furthermore, the driving assembly includes a hydraulic cylinder, a cylinder body of the hydraulic cylinder is movably connected to the support frame, and a piston rod of the hydraulic cylinder is movably connected to the folding arm assembly.

[0024] Further, the first propeller includes a housing, a driving mechanism, a driving shaft, a first impeller and a second impeller;

[0025] The shell is connected to the bottom end of the first hydrofoil, and a fluid channel and a containing cavity are arranged in the shell, wherein the fluid channel includes a water inlet and a water outlet; a pressurization area is arranged near the water outlet in the fluid channel, and the diameter of the inner wall of the pressurization area decreases along the water discharge direction;

[0026] The drive shaft is arranged inside the housing and connected to the drive mechanism;

[0027] The driving mechanism is disposed in the accommodating cavity and is used to drive the driving shaft to rotate;

[0028] The first impeller is fixedly connected to the driving shaft, the second impeller is rotatably connected to the driving shaft, and the first impeller is located upstream of the second impeller, and the second impeller is located inside the supercharging area.

[0029] Further, the auxiliary hydrofoil propulsion assembly includes a second connecting rod, a second hydrofoil and a second propeller;

[0030] The top end of the second connecting rod is connected to the bottom end of the hull;

[0031] The second hydrofoil is connected to the bottom end of the second connecting rod;

[0032] The second propeller is connected to the bottom end of the second hydrofoil.

[0033] By adopting the above technical solution, the foldable hydrofoil boat provided by the present invention has the following technical effects:

[0034] In the foldable hydrofoil boat provided in this embodiment, hydrofoil propulsion assemblies are arranged on both sides of the boat body, which increases the overall stability compared to the existing hydrofoil boat in which only one hydrofoil propulsion assembly is arranged at the bottom of the boat body;

[0035] The hydrofoil propulsion assembly is movably connected to the support frame through the folding arm assembly; the driving assembly is movably connected to the support frame and the folding arm assembly respectively, and the unfolding angle of the folding arm assembly relative to the horizontal plane is adjusted by the driving assembly, thereby adjusting the angle of the hydrofoil propulsion assembly relative to the horizontal plane to ensure the stability and safety of driving. The foldable hydrofoil boat of the present application can travel in relatively severe sea conditions and weather, and can be widely used in military, fishing, rescue, entertainment, transportation and other fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0037] Figure 1 A front view of a foldable hydrofoil boat provided by an embodiment of the present invention;

[0038] Figure 2 A side view of a foldable hydrofoil boat provided by an embodiment of the present invention;

[0039] Figure 3A diagram showing the unfolded state of a folding arm assembly of a foldable hydrofoil boat provided by an embodiment of the present invention;

[0040] Figure 4 A diagram showing a folded state of a folding arm assembly of a foldable hydrofoil boat provided by an embodiment of the present invention;

[0041] Figure 5 Another structural schematic diagram of a foldable hydrofoil boat provided by an embodiment of the present invention;

[0042] Figure 6 for Figure 1 A partial enlarged view of the middle A;

[0043] Figure 7 A schematic structural diagram of a first thruster provided in an embodiment of the present invention.

[0044] Reference numerals: 100 -hull, 200 -hydrofoil propulsion mechanism, 210 -support frame, 211 -transverse support, 212 -vertical rod, 213 -arc rod, 220 -folding arm assembly, 221 -upper support arm, 222 -lower support arm, 223 -limiting groove, 230 -driving assembly, 240 -hydrofoil propulsion assembly, 241 -first connecting rod, 242 -first hydrofoil, 243 -first propeller, 141 -shell, 1 42-driving mechanism, 143-driving shaft, 144-first impeller, 145-second impeller, 146-fluid channel, 147-accommodating chamber, 148-water inlet, 149-drain outlet, 150-pressurization area, 151-motor, 152-reducer, 153-sealing housing, 154-sealing element, 300-auxiliary hydrofoil propulsion assembly, 310-second connecting rod, 320-second hydrofoil, 330-second propeller. DETAILED DESCRIPTION

[0045] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0046] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", "third", etc., are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0047] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0048] like Figures 1 to 4 As shown, the foldable hydrofoil boat provided in the present application includes: a boat body 100 and a hydrofoil propulsion mechanism 200, wherein at least one hydrofoil propulsion mechanism 200 is provided and connected to the boat body 100;

[0049] The hydrofoil propulsion mechanism 200 includes a support frame 210, a folding arm assembly 220, a driving assembly 230 and a hydrofoil propulsion assembly 240;

[0050] The support frame 210 is disposed on the hull 100 to support the above-mentioned components;

[0051] Two hydrofoil propulsion assemblies 240 are provided, one of which is arranged on each side of the hull 100, and the hydrofoil propulsion assembly 240 is movably connected to the support frame 210 through the folding arm assembly 220;

[0052] The driving assembly 230 is movably connected to the support frame 210 and the folding arm assembly 220 respectively. The driving assembly 230 is used to adjust the deployment angle of the folding arm assembly 220 relative to the horizontal plane, and then adjust the deployment angle of the hydrofoil propulsion assembly 240 relative to the horizontal plane, so as to achieve the purpose of adapting to changes in the underwater environment.

[0053] In the foldable hydrofoil boat provided in this embodiment, hydrofoil propulsion assemblies 240 are respectively arranged on both sides of the boat body 100, which increases the overall stability compared to the existing hydrofoil boat in which only one hydrofoil propulsion assembly 240 is arranged at the bottom of the boat body 100;

[0054] The hydrofoil propulsion assembly 240 is movably connected to the support frame 210 via the folding arm assembly 220; the driving assembly 230 is movably connected to the support frame 210 and the folding arm assembly 220 respectively, and the deployment angle of the folding arm assembly 220 relative to the horizontal plane is adjusted by the driving assembly 230, thereby adjusting the angle of the hydrofoil propulsion assembly 240 relative to the horizontal plane, thereby ensuring the stability and safety of driving; thus, the foldable hydrofoil boat can travel in relatively severe sea conditions and weather, and can be widely used in military, fishing, rescue, entertainment, transportation and other fields.

[0055] In the preferred embodiment of the present application, refer to Figure 5 A hydrofoil propulsion mechanism 200 can be provided, and the hydrofoil propulsion mechanism 200 is located at one end of the length direction of the hull 100. When used, it not only increases the stability of the hull 100, but also facilitates the adjustment of the deployment angle of the folding arm assembly 220 and the hydrofoil propulsion assembly 240 relative to the horizontal plane.

[0056] In order to ensure the balance of the hull 100 in the length direction, an auxiliary hydrofoil propulsion assembly 300 is connected to the bottom of the hull 100, and the auxiliary hydrofoil propulsion assembly 300 is located at the other end of the hull 100 in the length direction, that is, at the opposite end of the hydrofoil propulsion mechanism 200. The hull 100 can move smoothly on the water under the action of the hydrofoil propulsion mechanism 200 and the hydrofoil propulsion mechanism 200 at the same time.

[0057] In the preferred embodiment of the present application, refer to Figure 1 and Figure 2 Two hydrofoil propulsion mechanisms 200 are provided, and are arranged respectively near the bow and the stern, so that the front and rear and both sides of the hull 100 can maintain balance when traveling on water, thereby improving the stability and safety of driving.

[0058] In the preferred embodiment of the present application, refer to Figure 3 and Figure 4 , the hydrofoil propulsion assembly 240 includes a first connecting rod 241, a first hydrofoil 242 and a first propeller 243;

[0059] The first connecting rod 241 is movably connected to the folding arm assembly 220, and the movably connected manner may be a shaft connection or a pin connection;

[0060] The first hydrofoil 242 is connected to the bottom end of the first connecting rod 241. Preferably, the first hydrofoil 242 is arc-shaped, and the upper surface of the first hydrofoil 242 is convex. Therefore, there is an upward pressure difference between the upper and lower surfaces of the first hydrofoil 242. When sailing, the dynamic lift of the hydrofoil boat bears a part of the static water buoyancy, and the hull 100 is lifted, reducing the displacement volume and wet surface area of ​​the hydrofoil boat; the first propeller 243 is connected to the bottom end of the first hydrofoil 242, and the first propeller 243 provides power for moving.

[0061] In a preferred embodiment of the present application, the auxiliary hydrofoil propulsion assembly 300 has the same structure as the above-mentioned hydrofoil propulsion assembly 240. Specifically, the auxiliary hydrofoil propulsion assembly 300 includes a second connecting rod 310, a second hydrofoil 320 and a second propeller 330; the top end of the second connecting rod 310 is connected to the bottom end of the hull 100; the second hydrofoil 320 is connected to the bottom end of the second connecting rod 310, and the second hydrofoil 320 has the same structure as the first hydrofoil 242; the second propeller 330 is connected to the bottom end of the second hydrofoil 320, and the structure of the second propeller 330 is the same as that of the first propeller 243.

[0062] In a preferred embodiment of the present application, the folding arm assembly 220 includes an upper support arm 221 and a lower support arm 222;

[0063] The upper support arm 221 is movably connected to the support frame 210 and the first connecting rod 241 in the hydrofoil propulsion assembly 240 respectively, and the movably connected manner may be a shaft connection or a pin connection;

[0064] The lower support arm 222 is movably connected to the support frame 210 and the first connecting rod 241 in the hydrofoil propulsion assembly 240 respectively, and the movably connected manner may be a shaft connection or a pin connection;

[0065] When used, the upper support arm 221 and the lower support arm 222 can be arranged in parallel so that the upper support arm 221 and the lower support arm 222 can move synchronously.

[0066] The driving assembly 230 includes a hydraulic cylinder, a cylinder body of the hydraulic cylinder is movably connected to the support frame 210, and a piston rod of the hydraulic cylinder is movably connected to the folding arm assembly 220. More specifically, the number of the hydraulic cylinder can be one, the cylinder body thereof is movably connected to the support frame 210, and the piston rod is movably connected to the upper support arm 221. When the piston rod is extended or retracted, the upper support arm 221 is swung, and then the upper support arm 221 drives the lower support arm 222 to swing synchronously, so as to adjust the swing angle of the first hydrofoil 242.

[0067] In addition, a hydraulic power element is also provided on the hull 100, which is connected to the hydraulic cylinder to provide power to the hydraulic cylinder.

[0068] In a preferred embodiment of the present application, the support frame 210 includes a first support frame in an inverted U shape and at least two transverse supports 211 arranged from top to bottom;

[0069] The first bracket includes a vertical rod 212 fixed on both sides of the hull 100 and an arc rod 213 connected between the vertical rods 212, the arc rod 213 is upwardly protruding, and the transverse bracket 211 is connected between the vertical rods 212. The transverse bracket 211 is movably connected to the corresponding upper support arm 221 and lower support arm 222 through an axis, that is, the upper support arm 221 is movably connected to the transverse bracket 211 located above through an axis, and the lower support arm 222 is movably connected to the transverse bracket 211 located below through an axis.

[0070] Preferably, refer to Figure 6 The upper support arm 221 and the lower support arm 222 are respectively provided with a limiting groove 223 at one end close to the vertical rod 212, so that the vertical rod 212 can be inserted into the limiting groove 223, and the arc rod 213 can be inserted into the limiting groove 223 of the upper support arm 221. Due to the coordinated use of the limiting groove 223, the vertical rod 212 and the arc rod 213, the upper support arm 221 and the lower support arm 222 can be prevented from swinging in the front-rear direction of the hull 100, thereby improving the stability of the upper support arm 221 and the lower support arm 222.

[0071] In a preferred embodiment of the present application, the first propeller 243 and the second propeller 330 have the same structure. Therefore, the structure of the first propeller 243 is used for explanation in this embodiment, and the structure of the second propeller 330 refers to the structure of the first propeller 243.

[0072] Specifically, refer to Figure 7 , the first propeller 243 includes a housing 141, a driving mechanism 142, a driving shaft 143, a first impeller 144 and a second impeller 145;

[0073] The shell 141 is connected to the bottom end of the first hydrofoil 242. The shell 141 is set to be cylindrical. The upper end of the shell and the front end (upstream position) and the rear end (downstream position) of the shell 141 of the first hydrofoil are all set to be conical. A fluid channel 146 and a accommodating cavity 147 are set in the shell 141; the fluid channel 146 is used to pass water, and the fluid channel 146 includes a water inlet 148 and a water outlet 149; preferably, the water inlet 148 is set at the bottom of the shell 141, and the water outlet 149 is set at one end of the axial direction of the shell 141;

[0074] A pressurization area 150 is provided near the drain port 149 in the fluid channel 146. The diameter of the inner wall of the pressurization area 150 decreases along the drain direction. Since the diameter of the pressurization area 150 decreases, the water flow can be pressurized, thereby increasing the flow rate.

[0075] The driving shaft 143 is disposed inside the housing 141 and connected to the driving mechanism 142;

[0076] The driving mechanism 142 is disposed in the accommodating cavity 147 and is used to drive the driving shaft 143 to rotate;

[0077] The first impeller 144 is fixedly connected to the drive shaft 143 and can rotate synchronously with the drive shaft 143. The second impeller 145 is rotatably connected to the drive shaft 143 to rectify the water flow discharged by the first impeller 144. In addition, the first impeller 144 is located upstream of the second impeller 145, and the second impeller 145 is located inside the boost zone 150.

[0078] In the first propeller 243 of the present application, since a pressurization zone 150 is provided in a position near the drain outlet 149 in the fluid channel 146 in the shell 141, the diameter of the inner wall of the pressurization zone 150 decreases along the drainage direction; the second impeller 145 is located inside the pressurization zone 150, and the first impeller 144 is located upstream of the second impeller 145. When the driving mechanism 142 drives the first impeller 144 to rotate through the driving shaft 143, the first impeller 144 propels the water flow into the pressurization zone 150, and the diameter of the inner wall of the pressurization zone 150 decreases along the drainage direction; the second impeller 145 located in the pressurization zone 150 accelerates the water flow and sprays it to the outside of the drain outlet 149, thereby increasing the propulsion force, thereby enhancing the propulsion power of the first propeller 243 and improving the driving effect.

[0079] The above-mentioned driving mechanism 142 includes a controller, a motor 151, a reducer 152 and a sealed housing 153; the controller is electrically connected to the motor 151, the motor 151 is connected to the input end of the reducer 152, the output end of the reducer 152 is connected to the driving shaft 143, and the sealed housing 153 is located at the output end of the reducer 152 and fixed in the housing 141.

[0080] One end of the sealing shell 153 close to the drain port 149 is a guide portion, which is in a conical cylindrical shape, and the diameter of the guide portion decreases along the drain direction.

[0081] A sealing element 154 is disposed between the sealing housing 153 and the driving shaft 143 , and a sealing element 154 is disposed between the output end of the speed reducer 152 and the driving shaft 143 . The sealing element 154 may be a water seal or an oil seal.

[0082] The foldable hydrofoil boat provided in the present application, when in use, the boat body 100 can be a fishing boat made of light foam material, a surfboard, or other types of miniaturized water equipment.

[0083] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A foldable hydrofoil boat, characterized in that: include: A hull, at least one hydrofoil propulsion mechanism connected to the hull; The hydrofoil propulsion mechanism comprises a support frame, a folding arm assembly, a driving assembly and a hydrofoil propulsion assembly; The support frame is arranged on the hull; The hydrofoil propulsion assemblies are respectively arranged on both sides of the hull, and the hydrofoil propulsion assemblies are movably connected to the support frame through a folding arm assembly; The driving assembly is movably connected to the supporting frame and the folding arm assembly respectively, and is used to adjust the unfolding angle of the folding arm assembly relative to the horizontal plane; The hydrofoil propulsion mechanism is provided with one, which is located at one end of the length direction of the hull, and the bottom of the hull is connected to an auxiliary hydrofoil propulsion assembly, and the auxiliary hydrofoil propulsion assembly is located at the other end of the length direction of the hull; The hydrofoil propulsion assembly comprises a first connecting rod, a first hydrofoil and a first propeller; The first connecting rod is movably connected to the folding arm assembly; The first hydrofoil is connected to the bottom end of the first connecting rod; The first propeller is connected to the bottom end of the first hydrofoil; The first propeller includes a housing, a drive mechanism, a drive shaft, a first impeller and a second impeller; The shell is connected to the bottom end of the first hydrofoil, and a fluid channel and a containing cavity are arranged in the shell, wherein the fluid channel includes a water inlet and a water outlet; a pressurization area is arranged near the water outlet in the fluid channel, and the diameter of the inner wall of the pressurization area decreases along the water discharge direction; The drive shaft is arranged inside the housing and connected to the drive mechanism; The driving mechanism is disposed in the accommodating cavity and is used to drive the driving shaft to rotate; The first impeller is fixedly connected to the driving shaft, the second impeller is rotatably connected to the driving shaft, and the first impeller is located upstream of the second impeller, and the second impeller is located inside the supercharging area; The folding arm assembly includes an upper support arm and a lower support arm; The upper support arm is movably connected to the support frame and the hydrofoil propulsion assembly respectively; The lower support arm is movably connected to the support frame and the hydrofoil propulsion assembly respectively; The driving assembly comprises a hydraulic cylinder, a cylinder body of the hydraulic cylinder is movably connected to the support frame, and a piston rod of the hydraulic cylinder is movably connected to the folding arm assembly.

2. The foldable hydrofoil boat according to claim 1, characterized in that: The support frame includes a first support frame in an inverted U shape and at least two transverse supports arranged from top to bottom; The first bracket includes vertical rods fixed on both sides of the hull and arc rods connected between the vertical rods, the arc rods are upwardly protruding, the transverse bracket is connected between the vertical rods, and the transverse bracket is movably connected to the corresponding upper support arm and lower support arm through an axis.

3. The foldable hydrofoil boat according to claim 2, characterized in that: The upper support arm and the lower support arm are provided with limiting grooves at one end close to the vertical rod, so that the vertical rod can be inserted into the limiting groove, and the arc rod can be inserted into the limiting groove of the upper support arm.

4. The foldable hydrofoil boat according to claim 1, characterized in that: The auxiliary hydrofoil propulsion assembly comprises a second connecting rod, a second hydrofoil and a second propeller; The top end of the second connecting rod is connected to the bottom end of the hull; The second hydrofoil is connected to the bottom end of the second connecting rod; The second propeller is connected to the bottom end of the second hydrofoil.

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