JPH08244687A - Course stabilizer for floating type water jet-propelled ship - Google Patents

Abstract

PURPOSE: To stably keep the course of a water jet-propelled ship receiving large wind pressure without using a check helm having large propulsion resistance for floating navigation. CONSTITUTION: Stabilizing fins 4A, 4B rotatable around the vertical axis within the prescribed range are suspended at the bow side bottom sections of hulls 1A, 1B, and a stabilizing fin operating device rotating the stabilizing fins 4A, 4B to generate a lift directing the bow toward the wind pressure direction side applied to the hull 1A is provided. The transverse force by the air pressure is offset by the lift of the stabilizing fins 4A, 4B provided on the bow side from the center of gravity of the hulls 1A, 1B, the turning mement centering on the center of gravity of the hulls 1A, 1B is offset, and the stable course can be kept. The propulsion resistance can be sharply reduced as compared with the check helm of water jet.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a course stabilizing device for improving needle holding performance in a water jet propulsion ship in which a hull is levitated by a hydrofoil to travel at high speed.

[0002]

2. Description of the Related Art Conventionally, a levitation type water jet propulsion ship is designed to reduce the propulsion resistance and travel at high speed by levitating the hull with hydrofoils, but on the contrary, the wind pressure area on the waterline becomes large. It is easily affected by the wind. For example, when wind pressure is applied from the port side, the bow of the boat is swept to the starboard side, so the "held rudder" is propelled while turning the bow of the water jet toward the port side and turning it toward the port side.
To correct the course.

[0003]

However, in the course stabilization by the rudder, there is a problem that the discharge water flow hits the bucket of the water jet to cause a decrease in thrust and an increase in resistance, resulting in a decrease in ship speed.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above problems and to provide a course stabilizing device for a floating water jet propulsion ship which can secure a stable course without steering and can reduce propulsion resistance. And

[0005]

In order to solve the above problems, a course stabilizing device for a floating water jet propulsion ship according to the present invention is rotatable around a vertical axis center within a predetermined range on a bow side bottom portion of a hull. A stable fin operating device is provided for suspending the stable fins and rotating the stable fins so as to generate a lift force that directs the bow toward the wind direction in response to the wind pressure received by the hull.

[0006]

According to the above construction, even if the hull receives wind pressure and is flown to the starboard side or the port side, the stable fin is rotated by the stable fin operating device, and the lift force generated by the stable fin is changed to the lateral ( The component force in the (port side) direction and the turning moment centered on the center of gravity of the ship can be canceled to prevent the bow from turning to the port side. Therefore, even if the wind pressure is applied obliquely from the front, the course can be stably held, and it is not necessary to steer with the water jet. Further, the propulsion resistance of the stabilizing fins is significantly smaller than the propulsion resistance of the rudder, so that it is possible to prevent a significant increase in the propulsion resistance due to the needle holding operation and suppress a decrease in the boat speed.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a high speed catamaran equipped with a course stabilizing device according to the present invention will be described below with reference to the drawings.

As shown in FIGS. 1 and 2, a front hydrofoil 2A is provided on the bow side between the left and right hulls 1A and 1B integrated by a deck 1C, and a rear hydrofoil 2B is provided on the stern. And water jet propulsion devices 3A and 3B provided at the stern of the hulls 1A and 1B, respectively, so that the hulls 1A and 1B are levitated during high speed navigation to reduce propulsion resistance. .

At the bottom of the left and right hulls 1A and 1B, the ship center of gravity G
Stabilizing fins 4 for stabilizing the course are provided on the bow side.
A and 4B are provided respectively. In this example,
Assuming that the hull length is l, it is arranged in front of the front hydrofoil 2A arranged at a position of 0.6l from the stern.
It is desirable to install it in the range of 55l to 0.70l. This is due to the fact that the center of gravity G near 0.5 l approaches 0.
If it is less than 55 l, the turning moment that acts to stabilize the course of the hulls 1A and 1B is too small due to the lift force obtained by the stabilizing fins 4A and 4B, and conversely, it is 0.
This is because, when approaching the bow side beyond 70 l, it becomes difficult to secure an installation space due to the bottom shape of the hulls 4A and 4B which becomes sharp.

The stabilizing fins 4A and 4B are shown in FIGS.
As shown in FIG. 2, for example, it is formed in an inverted trapezoidal airfoil cross section, and is rotatably hung vertically to the hulls 1A and 1B via a seal device and a bearing 6 by a rotary shaft 5 provided near the bow from the center. ing. The hulls 1A and 1B are provided with stabilizing fin operating devices 7 that rotate the stabilizing fins 4A and 4B in correspondence with the wind pressure direction, and lift force that opposes the component force (wind pressure lateral force) Wr for turning the bow by the wind pressure W. L is generated to stabilize the course of the water jet propulsion devices 3A and 3B. That is, hulls 1A and 1B
A fin rotating hydraulic cylinder 8 which is an example of a fin rotating device capable of rotating the stable fins 4A and 4B to the left and right through a rotating shaft 5 within a predetermined angle α °, a total of 2 × α °. Is provided, and the piston rod of the fin rotation hydraulic cylinder 8 is pin-connected to the rotation arm 9 fixed to the rotation shaft 5. The control valve 10 for controlling the fin rotation hydraulic cylinder 8 is operated via the stable fin control device 12 by the stable fin operation panel 11 arranged separately from the steering system. It should be noted that it is also possible to automatically control in cooperation with the automatic navigation device 13.

In the above structure, as shown in FIG. 5, when the wind pressure W is received from the port side during high-speed floating navigation, this wind pressure W is the wind pressure axial force Ws in the propulsion (thrust) direction and the wind pressure lateral force perpendicular thereto. The force Wr is considered separately, and a turning moment M for turning the bow to the starboard side is generated by the wind pressure lateral force Wr. At this time, the stable fin 4 is operated by the stable fin operating device 7.
By rotating A and 4B to the starboard side by a predetermined angle β °, induced resistance is generated by the vortex flow generated by the pressure difference around the stabilizing fins 4A and 4B, and a force P is generated on the stabilizing fins 4A and 4B. This force P is a drag force D which is a component force along the movement direction.
And the lift force L, which is a component force perpendicular to it, can be considered separately. Therefore, when the lift force L becomes equal to the wind pressure lateral force Wr, the wind pressure lateral force Wr is canceled and the turning moment M disappears. It is possible to prevent the bow from turning to the starboard side. At this time, the stable fins 4A,
The 4B propulsion resistance was about half that of the water jet bucket.

Therefore, the course can be stably maintained without the need for steering by the water jet propulsion devices 3A and 3B, which have been conventionally required, and the stabilizing fins 4 are provided.
Since the propulsion resistance of A and 4B is small, it is about half of the propulsion resistance of the rudder of the water jet, and it is possible to maintain the stable navigation course without significantly increasing the propulsion resistance against wind pressure. The needle holding performance can be dramatically improved.

By the way, it is possible to arrange a stabilizing fin on the stern side of the center of gravity G of the hulls 1A and 1B to correct the course. Stabilizing fins 4A and 4B provided on the bow side
Then, the lift force L acts in the direction of canceling both the wind pressure lateral force Wr and the turning moment M. However, in this water jet propulsion ship, when the stern is heeled to the left, it has the property of turning to the right. Then, although the lift acts in the direction of canceling the turning moment M, it does not work in the direction of canceling the wind pressure lateral force Wr, which causes a problem that the stern turns.

Although the catamaran is shown in the above embodiment, it may be a monohull.

[0015]

As described above, according to the course stabilizing device for a floating water jet propulsion ship of the present invention, even if the hull is blown to the starboard side or port side due to wind pressure, it is stabilized by the stable fin operating device. By rotating the fins, the lift generated by the stable fins cancels the component force in the lateral (port side) direction due to wind pressure and the turning moment centered on the center of gravity of the ship, and prevents the bow from turning to the port side. it can. Therefore, even if it receives wind pressure from diagonally forward,
The course can be held stably, and there is no need to steer with a water jet. Further, the propulsion resistance of the stabilizing fins is significantly smaller than the propulsion resistance of the rudder, so that it is possible to prevent a significant increase in the propulsion resistance due to the needle holding operation and suppress a decrease in the boat speed.

[Brief description of drawings]

FIG. 1 is a side view of a hull showing an embodiment of a water jet propulsion ship having a course stabilizing device according to the present invention.

FIG. 2 is a schematic bottom view of the ship.

FIG. 3 is a side view showing a stabilizing fin of the course stabilizing device.

FIG. 4 is a configuration diagram showing a stabilizing fin operating device of the course stabilizing device.

FIG. 5 is an explanatory view of a lift force generated on a stabilizing fin of the course stabilizing device.

[Explanation of symbols]

 1A, 1B Hull 1C Deck 2A, Front Hydrofoil 2B Rear Hydrofoil 3A, 3B Water Jet Propulsion Device 4A, 4B Stabilizing Fin 5 Rotating Shaft 6 Bearing 7 Stabilizing Fin Operating Device 8 Fin Rotating Cylinder 9 Rotating Arm 10 Control valve 11 Stabilizing fin 12 Stabilizing fin control device 13 Automatic navigation device W Wind pressure Wr Wind pressure lateral force L Lifting force

Claims (1)

[Claims] 1. A stable fin, which is rotatable about a vertical axis in a predetermined range, is hung on the bottom of the bow of the hull, and lift force is generated to direct the bow toward the wind direction in response to the wind pressure received by the hull. A course stabilizing device for a floating water jet propulsion ship, characterized in that a stabilizing fin operating device for rotating the stabilizing fin is provided in the.