JP2000344179A - Hull shape of high-speed catamaran - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hull shape of high-speed catamaran that can reduce wave-making resistance. SOLUTION: Each hull is established hanging down at lower part on both sides of horizontal main body on the hull of a catamaran. The cross section is made in a part at least lower than the waterline at the stern of each hull. A distance L1 from a center line (a) of each hull to the inside surface S1 toward the center of the ship body is made to be shorter than a distance L2 from a center line (a) to the outer surface S2 toward the outside of the ship body. Then the sea surface interval between both hulls is widened to reduce the flow velocity at this part and the flow velocity at the inside sea surface between both hulls and at the outside sea surface outside of the hull are made to be almost the same.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hull shape of a high-speed catamaran.

[0002]

2. Description of the Related Art Many catamaran are constructed as high-speed ships in view of their stability and securing an area on a deck. Generally, when a high-speed catamaran is constructed, the hull is designed so that wave-making resistance is as small as possible. In other words, the wave generated from the bow is naturally taken into consideration so as to reduce the wave generated from the stern. For example, in the case of a monohull, for example, there is a demand for a hull shape in which the stern shape is variously changed to reduce the wave generated from the stern.

By the way, in the case of a catamaran, trunks are provided on the left and right. Conventionally, the shape of each of these trunks has been changed by changing the shape of a single-hull with a small wave-making resistance to the interval between the catamaran and It was optimized and used in consideration of drainage volume. As described above, most of the optimized body has a shape which is symmetrical with respect to the center line.

[0004]

As described above, in the case of a catamaran provided with a pair of left and right hulls having a symmetrical cross-sectional shape, an inner sea surface portion between the two hulls is required. However, the flow of seawater is different from the outer sea surface portion outside the both trunk portions. For example, at the inner sea surface, the flow velocity is faster than at the outer sea surface, that is, the flow velocity is different between the trunk and the outer of the trunk, and the wave difference generated at the stern due to the pressure difference is large. There was a problem of becoming.

Accordingly, an object of the present invention is to provide a hull shape of a high-speed catamaran capable of reducing wave-making resistance.

[0006]

In order to solve the above problems, the hull shape of the high-speed catamaran of the present invention is as follows. In the cross section of at least a portion below the waterline on the stern side of each hull, the distance from the center line of each hull to the inner surface closer to the hull center is from the center line to the outer surface closer to the hull outer side. It is shorter than the distance.

[0007] According to the above configuration, on the stern side of each trunk, the distance from the center line to the inner surface is shorter than the distance to the outer surface, so that the sea surface distance between the two trunks is widened. The flow velocity at the lever portion is reduced, that is, the flow velocity at the inner sea surface between the trunks and the outer sea surface outside the trunk is substantially equal, and the wave making resistance is reduced.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The hull shape of a high-speed catamaran according to an embodiment of the present invention will be described below with reference to FIGS. As shown in FIG. 1, the sectional shape of the hull 1 of this high-speed catamaran is, for example, a horizontal main body 2 in which necessary cabin (steering room, cabin, cargo room, etc.) is arranged, and a horizontal main body 2 A pair of left and right trunks 3 provided to hang down at the left and right positions.
The outer shape of the cross section of each body 3 is substantially parabolic at least at a portion below the waterline.

The sectional shape of each of the trunks 3 will be described in detail. As shown in FIG. 2, in the front half of the bow, a parabolic shape symmetrical with respect to the center line a of the trunk 3 as in the prior art. As shown in FIG. 3, the rear half of the stern side has a substantially inverted trapezoidal shape.
The shape is such that it is asymmetrical with respect to the center line a of the body 3.

That is, in the same cross section of the rear half of the stern side of each body 3, the distance L ₁ from the center line a to the inner surface S ₁ near the hull center line b is the distance from the center line a toward the hull outward. Is made shorter than the distance L ₂ to the outer surface S ₂ of the. Note that L ₁ and L ₂ shown in FIG.
The distance in the cross section of the rear end of the hull is shown. Curves A to D show the outlines at positions set at predetermined intervals from the center to the stern side in the bow and stern direction.

As described above, the cross-sectional shape of each body 3 is asymmetrical so that the distance from the center line to the inner surface is shorter than the distance to the outer surface. It is wider than the sea surface gap between the trunks in the case of left-right symmetry, so the flow velocity at this part is slow, and the flow velocity at the inner sea surface part between the trunk parts and the flow velocity at the outer sea surface part outside the trunk part are almost That is, the height difference (sea level difference) between the inner sea surface portion and the outer sea surface portion is almost eliminated, so that the wave making resistance (hull resistance) generated at the stern portion can be reduced. Briefly, Figure 1
As shown by the broken line in FIG.
By shaping the shape of “a”, the horizontal area of the inner sea surface is increased, and the flow velocity at the inner sea surface is reduced.

FIG. 4 is a graph showing the present embodiment (the present invention).
2 shows the relationship between the Froude number and the total resistance of the hull in the hull shape according to the above and the conventional hull shape. From this graph, it is found that the total resistance of the hull shape according to the present embodiment (shown by a solid line) is smaller and superior to the total resistance of the hull shape according to the prior art (shown by a dashed line). I understand.

[0013]

As described above, according to the structure of the present invention, on the stern side of each trunk, the distance from the center line to the inner surface is shorter than the distance to the outer surface. The sea surface spacing between them is widened and the flow velocity in this part becomes slower, that is, the flow velocity in the inner sea surface part between the trunk and the outer sea surface part outside the trunk is almost equal, so the wave making generated at the stern part Resistance can be reduced.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a hull shape of a high-speed catamaran according to an embodiment of the present invention.

FIG. 2 is a diagram showing a cross-sectional shape of a trunk portion on the bow side in the embodiment.

FIG. 3 is a diagram showing a cross-sectional shape of a trunk portion on the stern side in the embodiment.

FIG. 4 is a graph showing the relationship between the Froude number and the total resistance in the hull shape of the embodiment and the conventional hull shape.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Hull 2 Horizontal main body 3 Body

Claims (1)

[Claims] 1. A hull shape of a high-speed catamaran having hulls provided on the left and right sides of the hull, respectively, wherein at least a cross section of the stern side of the hull side below a waterline is a center of each hull. A hull shape for a high-speed catamaran, wherein the distance from the line to the inner surface near the center of the hull is shorter than the distance from the center line to the outer surface near the hull.