JPH1111384A - Method and apparatus for preventing pitching of hull - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To prevent vertical sway of a hull with a simple device configuration even when a ship is stopped. SOLUTION: This method is a method for preventing pitching of a hull, wherein a strut having a hydrofoil at its tip is reciprocated obliquely in a phase opposite to the pitching phase of the hull. The apparatus also includes a strut 2 extending obliquely downward into the water from inside the ship 1, a hydrofoil 3 attached to the tip of the strut 2, and a strut 2 attached to the rear end of the strut 2 to drive the strut 2 in an oblique direction. And a control unit 6 for controlling the drive mechanism 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and a device for preventing a hull from pitching.

[0002]

2. Description of the Related Art Hull of a hull is caused by pitching,
There are rolling (rolling), lateral movement (yawing), and the like. Preventive measures are roughly classified into the following methods. (1) A method of balancing by changing the center of gravity of the ship by moving seawater and weights in the rocking tank. (2) A method of reducing sway using a propulsion device (propeller, water jet, etc.). (3) A method of using a lift acting on a fin to reduce the motion of a ship. (4) A method of adding a fluid nozzle to the fin to reduce the motion of the ship.

Japanese Patent Application Laid-Open No. Hei 7-228292 discloses a method of reducing the sway of a ship by using the lift acting on the fins of the above (1) to (4).

The technique disclosed in the above publication includes a strut which descends from the storage room near the end of the hull to the bottom of the hull by a lifting drive mechanism, and fins for preventing pitching mounted on the strut. The fin is moved up and down together with the strut by controlling a lifting drive mechanism via a control system based on a signal from a pitch sensor,
A lift is generated in the fins by the water flow flowing into the fins at an angle of attack corresponding to the direction of the combined vector of the moving speed of the fins in the vertical direction and the flow velocity, and the vertical motion of the hull is canceled by the moment due to the lifts. It is.

[0005]

However, in the prior art disclosed in the above-mentioned Japanese Patent Application Laid-Open No. Hei 7-228292, lift due to the water flow on the fin wing surface can be expected for pitching during sailing. In the vertical pitching, no lift is generated by the water flow on the fin wing surface, so that only a damper effect due to vertical movement can be expected. Therefore, the effect of preventing pitching at the time of stopping the ship cannot be expected.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problem of preventing vertical swing when the boat is stopped.

[0007]

A first means for solving the above-mentioned problem is to reciprocate a strut having a hydrofoil at its tip in a diagonal direction in a phase opposite to the pitching phase of the hull. This is a method for preventing pitching.

A second means for solving the above-mentioned problems is to provide a strut extending obliquely downward into the water from inside the ship, a hydrofoil attached to the tip of the strut, and a strut attached to the rear end of the strut. A hull pitching prevention device comprising a drive mechanism for driving in an oblique direction and a control unit for controlling the drive mechanism.

According to the first and second means, when the hull sways when the hull stops, a driving mechanism that drives the hull obliquely up and down via the control unit by detecting a sensor, and determines the phase of the sway of the hull. With the strut of the hydrofoil moved up and down diagonally in the opposite phase, the lift speed of the hydrofoil is increased by the moving speed of the hydrofoil in the oblique vertical direction and the angle of attack corresponding to the angle of attachment of the hydrofoil to the strut. The lift caused by the lift cancels the pitching of the hull.

Further, since the hydrofoil is moved obliquely up and down, it is necessary to generate a lift acting on the hydrofoil, a force based on acceleration acting when starting from a standstill and stopping from a moving state, and when generating a steady lift. The acting fluid force is
Acts as pitching prevention.

Further, according to the second means, since the strut is only reciprocated in the oblique direction, the apparatus can be made simple.

[0012]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a perspective view of an apparatus for preventing pitching of a hull according to the present invention, wherein 1 is a hull, 1a is a bow of the hull 1,
1b is a ship bottom.

Reference numeral 2 denotes a strut extending obliquely from the bottom 1b of the hull 1;
Is installed at a predetermined angle of attack via the mounting portion 4.

FIG. 2 is a side cross-sectional view schematically showing a hull pitching prevention apparatus according to the present invention from the side.

A strut 2 having a hydrofoil 3 attached to its tip.
Is provided obliquely at a predetermined angle θ with respect to the bottom 1 b of the hull 1, and is attached to a drive mechanism 5 inside the hull 1.

The drive mechanism 5 is provided with a cylinder mechanism 5a as an example, and moves the strut 2 up and down in an oblique direction.

Reference numeral 6 denotes a control unit for controlling the drive mechanism 5, which receives information on the sway of the hull from a tilt sensor and an acceleration sensor (not shown) by a signal and drives the drive mechanism 5 in the opposite phase to the wave.

FIG. 3 is a graph showing the force acting on the hydrofoil according to the present invention. The hydrofoil 3 according to the present invention has a lift 7 acting by driving the hydrofoil in an oblique direction, starting from a standstill, and The force 8 based on the acceleration acting when stopping from the moving state and the fluid force 9 acting other than when a steady lift is generated function to prevent pitching.

FIGS. 4A and 4B are side views showing the relationship between the hydrofoil and the pitching of the hull 1 according to the present invention.

[0021] In FIG. 4 (a), in case of rotating R ₁ in the direction of the right end of the hull 1 is submerged, hydrofoil 3 is moved downward to exert a force F ₁ against it.

In FIG. 4B, when the left end of the hull 1 rotates R ₂ in the sinking direction, the hydrofoil 3 is moved upward to apply a force F ₂ against it.

FIG. 5 is a perspective view of a second embodiment in which the present invention is applied to a catamaran. In FIG. 5, struts 2a and 2b are respectively attached to the catamaran hulls 1c and 1d at an angle, and both ends of the hydrofoil 3 are supported at lower ends thereof via attachment portions 4.

According to this structure, since the hydrofoil 3 is of a both-end supporting type, there is an advantage that a large wing area can be secured.

The structure in which the struts 2a and 2b support both ends of the hydrofoil 3 can be applied to a single hull and a wide hull.

FIGS. 6 (a), 6 (b) and 6 (c) are front views showing an embodiment of a hydrofoil mounting structure according to the present invention to the catamaran.

FIG. 6A shows the strut 2 of the hydrofoil 3.
The structure is such that a and 2b are inclined in a side view and are provided vertically in a front view.

FIG. 6B shows the strut 2 of the hydrofoil 3.
The structure is such that a and 2b are inclined in a side view and are provided at an angle that opens downward in a C-shape in a front view. With this structure, the wing area of the hydrofoil 3 can be set large.

FIG. 6C shows the strut 2 of the hydrofoil 3.
The structure is such that a and 2b are inclined in a side view and provided in an inverted C-shape in a front view and open at an angle. With this structure, the strength of the structural system including the strut can be increased.

FIGS. 7 (a), 7 (b) and 7 (c) are plan views of struts 2a and 2b supporting both ends of the hydrofoil 3 cut along the water surface, and show an embodiment of the arrangement in the longitudinal direction of the hull.

FIG. 7A shows a state in which the struts 2a and 2b are arranged parallel to the hull center line.

FIG. 7B shows a structure in which the struts 2a and 2b are arranged so as to close forward with respect to the hull center line. When the auxiliary wing is attached to the trailing edge of the hydrofoil 3 by this structure, it is advantageous when it is necessary to increase the area of the auxiliary wing.

FIG. 7C shows a structure in which the struts 2a and 2b are arranged so as to open forward with respect to the center line of the hull. With this structure, the resistance acting on the struts 2a and 2b can be reduced.

[0034]

As described above, the present invention enables control of pitching prevention not only at the time of sailing but also at the time of stopping the ship.

In addition, since the control is simple up / down driving control in a diagonal direction, the apparatus is simple.

[Brief description of the drawings]

FIG. 1 is a perspective view of a hull pitching prevention apparatus according to the present invention.

FIG. 2 is a side sectional view schematically showing a hull pitching prevention apparatus according to the present invention from a side.

FIG. 3 is a graph showing a force acting on a hydrofoil in the present invention.

4A and 4B are side views illustrating the relationship between the hydrofoil and the pitch of the hull according to the present invention, wherein FIG. 4A is a state in which a bow sinks, and FIG. This shows a state where the part is raised.

FIG. 5 is a perspective view of a second embodiment in which the present invention is applied to a catamaran.

6 (a), 6 (b) and 6 (c) are front views showing an embodiment of a structure for attaching a hydrofoil to the catamaran according to the present invention.

FIGS. 7A, 7B, and 7C are plan views of struts supporting both ends of a hydrofoil 3 of the present invention, which are cut along a water surface line.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Hull 1a Bow 1b Ship bottom 2 Strut 3 Hydraulic wing 4 Mounting part 5 Drive mechanism 6 Control part 7 Force based on lift 8 Force applied when pitching acceleration is large 9 Force based on fluid resistance

Claims (2)

[Claims] 1. A method for preventing pitching of a hull, wherein a strut having a hydrofoil at its tip is reciprocated in an oblique direction in a phase opposite to the pitching phase of the hull. 2. A strut extending obliquely downward into the water from the ship, a hydrofoil attached to a tip of the strut, a drive mechanism attached to a rear end of the strut and driving the strut in an oblique direction, and A hull pitching prevention device, comprising: a control unit that controls a driving mechanism.