JPS5973384A - Device for reducing resistance to hull - Google Patents

Abstract

PURPOSE:To reduce creation of water flow separation and resistance to a hull, by providing a plate-like current fin at an upwardly slant portion of a bottom of a stern. CONSTITUTION:There is provided a plate-like current fin 3 at an upwardly slant portion 2 of a bottom portion of a stern of a hull 1. Water flows along the current fin 3 as depicted by an arrow S, thereby reducing creation of water flow separation and resistance to the hull. Further, a part of lift generated at the current fin 3 may be utilized as a propulsion force.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hull resistance reducing device that reduces the occurrence of water flow separation in the cut-up portion of the stern bottom of a ship.

In a conventional ship having a raised portion 2 at the stern bottom of the hull 1 as shown in FIG. This causes hull resistance, increases fuel consumption, and has a negative effect on the maneuverability of the hull 1.

Therefore, the present invention was made with the aim of solving the above-mentioned conventional problems and reducing the hull resistance, thereby saving fuel and improving the maneuverability of the hull. 3. That is, the hull resistance reducing device of the present invention is constructed by providing plate-shaped rectifying fins on the cut-up portion of the stern bottom of the hull, but it is not possible to make the rectifying fins protrude below the baseline of the ship's bottom. This is a more preferable configuration.

Embodiments of the present invention will be explained below with reference to the drawings.
Embodiment 1 The figure is an overall perspective view of a hull provided with a hull resistance reducing device according to Embodiment 1 of the present invention, viewed from below, and FIG.
It is a schematic diagram of the main part of the stern shown in the figure.

In the ship of this embodiment 1 (/(), as shown in FIG. This straightener 1.]in6 has its front end connected to the third
As shown in the figure, it is supported by a support member 4 so as to protrude by a depth E below the baseline indicated by an arrow B of the hull 1.

By providing such a rectifying fin 3, the water flow is directed by the arrow S in the stern bottom portion of the hull 1 moving in the direction of the arrow F.
The water flows along the rectifying fins 6 as shown in FIG. 1, and the separation area H of the water flow shown by diagonal lines in FIG.

Note that the front end of the rectifier fin 6 is made to protrude by an amount E from the baseline B, making it E)0, but E)
)0, and when the hull 1 is docked, the support member 4 is moved so that the rectifying fins 3 are set to E x O.
It can also be supported by

Still, in FIG. 3, the plate-shaped rectifying fin 3 is formed into a wing shape with a concave upper surface and a convex lower surface.
Like the rectifying fin 3 constituting the hull resistance reducing device according to the second embodiment of the present invention shown in FIG. 4, it may be formed into a wing shape with two convex surfaces and a concave lower surface.

Therefore, the results of a resistance experiment with the rectifying fins 6 not shown in Examples 1 and 2 attached to the hull 1 are as follows.
As a result of comparing with the conventional hull 1 without the straightening fins 6, by providing the straightening fins 3 of the present invention, a maximum of 14
% resistance reduction was confirmed.

In addition, in the above experimental results, it was observed that when the rectifier fins 6 protruded below the baseline B of the bottom of the hull 1, the largest reduction in resistance was observed compared to when they did not protrude, and the residual resistance coefficient It was confirmed that the total resistance coefficient was reduced by about 16 to 20%, and the total resistance coefficient was reduced by about 10 to 14. In this case, especially, the rectification on the soil surface side of the rectifier fins 3 was performed well, and the separation area H' was reduced. Is it rut? lt
It was found that the rectifying fins 6 serve to enhance the rectifying effect rather than to reduce resistance.

Therefore, if the hull resistance reducing device of the present invention is applied to a ship having a cut-up portion at the stern bottom of the hull, the effect of the rectification effect at the stern bottom will be enhanced, and the hull resistance will be significantly reduced. This has the effect of making the ship more fuel efficient and improving the maneuverability of the ship.

Note that the present invention can be effectively applied to both self-propelled and towed ships.

[Brief explanation of the drawing]

FIG. 1 is a schematic explanatory diagram of the main part of the stern of a conventional hull, FIG. 2 is an overall perspective view of the hull equipped with a hull resistance reducing device according to an embodiment of the present invention, viewed from below, and FIG. FIG. 4 is a schematic explanatory view of the main part of the stern part of the ship body in Embodiment 2 of the present invention. 1... Hull, 2... Cut-up portion, 6... Rectifier fin, B... Baseline. 446

Claims (1)

[Scope of Claims] 1. A hull resistance reduction device characterized in that a plate-shaped rectifying fin is provided in the cut-up portion of the stern bottom of the hull. 2. The hull resistance reducing device according to claim 1, wherein the rectifying fins provided on the cut-up portion of the stern bottom of the hull protrude below the baseline of the hull bottom.