JPH11180379A - Stern backwash reducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the height of the backwash caused by the stern wave by mounting plural foil bodies having the blade-shaped section on a stern end toward the rear in parallel, with each other at specific intervals. SOLUTION: Two sheets (or three or more sheets) of foil bodies 5 are mounted on a transom stern 1a of a stern end 1 toward the rear at a specific interval α in parallel with each other. Each foil body 5 has a length almost equal to or slightly longer than a width of a stern end 1, and the stern wave generated at the rear of the stern end 1 is parted in the longitudinal direction by the foil bodies 5, whereby the wave height of the backwash can be reduced. It is preferable that each foil body 5 comprises symmetrical or dissymmetrical blade-shaped section to reduce the resistance, and each foil body 5 is inclined obliquely upward toward the rear with a specific angle β. Whereby the thrust as the component toward the front is generated on the force synthesized by the drag and the lift, and the hull is advanced by this thrust, so that the resistance of the foil. bodies 5 are reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stern trawl reducing device for reducing the wave height of a stern trawl.

[0002]

2. Description of the Related Art Conventionally, when a high-speed ship is navigated along the coast or in a harbor, as shown in FIG. 4, the wave height H1 of the stern wave 2 generated by the stern wave generated behind the stern end 1 is high. , Boats and aquaculture cages may be adversely affected.

Therefore, as shown in FIG. 5, a substantially triangular wedge 3 is provided on the bottom surface of the stern end 1, and the stern end 1 is lifted by the lift L which is a component of the force P generated on the wedge 3. As shown in FIG. 6, a substantially triangular flap 4 extending obliquely downward from the end face of the stern end 1 toward the rear is provided, and the force P generated on the flap 4 is reduced.
It is considered that the stern wave 1 is lifted by the lift L which is the component force of the stern, and the stern wave is reduced by increasing the apparent hull length.

[0004]

In the wedge 3 and the flap 4 described above, the effect of reducing the stern wave is small.
High towing waves 2 having high wave heights H2 and H3 are generated and forced to decelerate when navigating along coasts and ports.

SUMMARY OF THE INVENTION In view of the above problems, an object of the present invention is to provide a stern trawl reducing device that can reduce the wave height of a trawl by a stern wave.

[0006]

In order to achieve the above object, the invention according to claim 1 is characterized in that a plurality of wing bodies having a wing-shaped cross section are arranged in parallel at a predetermined interval behind the stern end. And

According to the above configuration, the stern wave is divided by the plurality of wings arranged in parallel at a predetermined interval behind the stern end, so that the wave height of the stern wave caused by the stern wave can be reduced. .

A second aspect of the present invention is characterized in that, in the first aspect of the invention, a plurality of wings are arranged in parallel at a predetermined interval behind the stern end. According to the above configuration, by appropriately selecting the inclination angle of each wing body, a component force (thrust) in the forward direction is generated in the force generated in each wing body, and the thrust acts on the hull, resulting in the resistance of the wing body. Can be reduced.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIGS. 1 and 2 show a stern towing device according to an embodiment of the present invention, in which two (or three or more) stern wave sterns 1a at the stern end 1 are spaced rearward from a transom stern 1a. ) Are arranged in parallel with each other. 6 is a mounting stay for connecting the rear wing body 5 to the stern end 1, 7 is a connecting plate for connecting the wing bodies 5 to each other, L is a waterline.

Each of the wings 5 is substantially the same as or slightly longer than the width of the stern end 1, and the stern waves generated behind the stern end 1 are separated by the respective wings 5 from front to back. The wave height h of the towing wave 2 can be reduced.

As shown in FIG. 3, each of the wings 5 is formed into a symmetric or asymmetrical airfoil cross section to reduce resistance, and each wing 1 is inclined obliquely upward toward the rear by a predetermined angle β.
It is preferable to incline. As a result, a thrust T, which is a forward component, is generated in a force P synthesized by the drag D and the lift L generated in the wing 1, and the hull is propelled by the thrust T, resulting in the wing 1 Resistance is reduced.

[0012]

According to the first aspect of the present invention, the stern wave is divided by a plurality of wings arranged in parallel at a predetermined distance behind the stern end. Can be reduced.

According to the second aspect of the present invention, by appropriately selecting the inclination angle of each wing body, a component force (thrust) in the forward direction is generated in the force generated in each wing body, and the thrust acts on the hull. ,
As a result, the resistance of the wing body can be reduced.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a stern towing device according to an embodiment of the present invention.

FIG. 2 is a longitudinal sectional view of the same.

FIG. 3 is an enlarged view of a main part showing the action of reducing the towing.

FIG. 4 is a side view showing a conventional example.

FIG. 5 is a side view showing an example of a conventional improvement.

FIG. 6 is a side view showing another example of the conventional improvement.

[Explanation of symbols]

 Reference Signs List 1 stern end 2 wake 5 wing body α spacing between wing bodies β inclination angle of wing body L lift T thrust

Claims (2)

[Claims] 1. A stern trawl reduction device comprising: a plurality of wings having an airfoil cross-section arranged in parallel at a predetermined interval behind a stern end. 2. The stern trawl reduction device according to claim 1, wherein the plurality of wings are inclined obliquely upward at a predetermined angle toward the rear.