JPS6123511Y2 - - Google Patents

Description

[Detailed explanation of the idea] [Technical field of invention] This invention relates to a semi-submersible multihull.

[Prior art]

In principle, this type of semi-submersible multihull has the potential to become a ship with excellent high-speed performance and seaworthiness, and it also has a large deck area, which can improve cargo handling efficiency and work efficiency. Although it can be widely used in the fields of future maritime transportation and ocean development, there are many points that need improvement, such as propulsion performance, maneuverability, course stability, oscillation performance, and stability at high speeds.

[Purpose of invention]

The purpose of the present invention is to improve the above-mentioned performance of a semi-submersible multihull so that it can be put to practical use.

[Structure of the idea]

That is, the semi-submersible multihull of the present invention is a semi-submersible multihull in which an upper hull and a plurality of lower hulls arranged below the upper hull at predetermined intervals are connected by struts. The rear end of the rear strut extends rearward from the rear end of the lower hull, and the lower hull is flattened, and the lower hull has its maximum width at the rear of the lower hull and extends from the front end of the lower hull to the maximum width. It is characterized by its width becoming gradually wider towards the rear.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

First, FIGS. 1 to 4 show the first embodiment, and as shown in FIGS. 1 and 2, below the upper hull 1 are two lower hulls 2 and 2.
is arranged parallel to this upper hull 1 with a predetermined distance therebetween. Further, these two lower hulls 2, 2 are also arranged in parallel with an appropriate interval between them. The lower hulls 2, 2 arranged in this manner are connected to the upper hull 1 by struts 3, 4 (see FIG. 3) each having a streamlined horizontal cross section.

These struts 3 and 4 are connected to the lower hulls 2 and 2.
are arranged at the front end and the rear end, respectively. In order to attach the rudder 5 to the rear strut 4, the rear end thereof is shaped to protrude rearward beyond the rear ends of the lower hulls 2, 2, as shown in FIG. Therefore, the center of floating surface O, which is determined by the catchment area of the struts 3 and 4, is closer to the strut 4 at the rear.

By the way, generally speaking, when a semi-submerged ship sails,
A drop in the water level occurs at the rear ends of the lower hulls 2, 2, where the cross-sectional area gradually decreases. This phenomenon is influenced by the rear shape of the lower hulls 2, 2, submerged depth, ship speed, etc. That is, the lower the water level becomes larger as the downward curvature of the rear shape of the lower hulls 2, 2 becomes larger, the submerged depth becomes smaller, or the ship speed becomes larger. If this water level drop is large, propulsion performance will deteriorate, and the propeller will be exposed above the water surface, posing a problem to navigation.

However, it is surprising that the water level drop can be prevented by extending the rear ends of the rear struts 4 rearward from the rear ends of the lower hulls 2, 2, as described above.

Furthermore, as shown in FIG. 2, each strut 3, 4 is provided with an expanded portion that gradually expands upward above the water line, and the upper hull 1 is fixed onto this expanded portion. There is. This expanded portion is provided over substantially the entire length of each strut 3,4. Generally, in such a semi-submersible multihull, the joints between the struts 3, 4 and the upper hull 1 are subjected to a large wave bending moment, but the expanded portion is used to increase the rigidity of the joints between the struts 3, 4 and the upper hull 1. In addition, it has the function of increasing lateral restoring force and increasing lateral stability when the hull is significantly heeled and the water line reaches the widening part.

Further, in this embodiment, as shown in FIG. 3, these lower hulls 2, 2 are formed so that their widths gradually become wider from their front ends toward the rear, and reach their maximum width near their rear ends. It is configured as follows. Further, as shown in FIG. 1, when these lower hulls 2, 2 are viewed from the side, their upper and lower end surfaces are formed substantially parallel except for the front and rear ends.

Therefore, the ratio of the width DB 2 to the thickness DH ₂ at the rear width direction cross section A ₂ of each lower hull 2 is _{DB 2 /} DH ₂
is the ratio of the width DB ₁ and the thickness DH ₁ of the front width direction cross section A ₁
It is set larger than DB ₁ /DH ₁ .

Furthermore, for example, in FIG. 3, the longitudinal cross section of the lower hulls 2, 2 near the maximum width is
As shown in the figure, it is shaped like an airfoil.

Now, when a semi-submersible multihull with lower hulls 2 and 2 as described above is sailed, as the ship increases in speed, the center of force moves toward the stern, and the attitude of the ship changes to lower the stern. try to change it.

However, this ship has lower hull 2 shown in Figure 4.
As the speed increases due to the action of the airfoils 2 and 2, an upward force (in the direction of the arrow in Figure 4) acts on the rear of the lower hulls 2 and 2, so this lifting force offsets the force that lowers the stern and stabilizes the hull's attitude. .

In addition, by setting the maximum width of the lower hulls 2, 2 near their rear ends, the buoyancy center B moves to the rear of the lower hulls 2, 2, so the buoyancy center O and the buoyancy center B are changed as shown in Figure 1. Can be matched.

As a result, since the positions of the opposing forces acting on the center of buoyancy O and the center of buoyancy B are on the same perpendicular line, no rotational moment is applied to the hull due to these forces, resulting in pitching due to up-and-down rocking, or There is no vertical motion induced by pitching, and the attitude of the ship becomes more stable.

On the other hand, FIGS. 4 to 8 show the second embodiment, and as in the first embodiment, the lower hulls 2a, 2a are separated from their front ends as shown in FIG. They are formed so that their width gradually increases toward the rear, and are configured to have a maximum width near their rear ends.

Further, as shown in FIG. 5, these lower hulls 2a, 2a are configured such that their upper and lower end surfaces become gradually narrower from the front toward the rear.

To describe this in more detail with reference to FIG.
The ratio DB ₂ /DH ₂ of the width DB ₂ and the thickness DH ₂ at A ₂ is set to be larger than that of the width direction cross section of the rear portion of the lower hulls 2, 2 of the first embodiment. That is, the rear portions of the lower hulls 2a, 2a are further flattened.

As shown in FIG. 8, the longitudinal section near the maximum width of each of the lower hulls 2a has an airfoil shape that is thinner than that of the first embodiment, so the water resistance is higher than that of the first embodiment. There is a small advantage. Other effects are the same as in the first embodiment.

The best position for the maximum width of the lower hull is about 1/4 of its total length from the rear end.

[Effect of idea]

As described above, the present invention provides a semi-submersible multihull in which an upper hull and a plurality of lower hulls arranged below the upper hull at predetermined intervals are connected by struts, and the rear end of each rear strut is The lower hull is extended rearward from the rear end of the lower hull, and the lower hull is made flat, and the lower hull is gradually made wider from the front end to the rear end, so that the propulsive performance, maneuverability, and course are improved as follows. Stability, oscillation performance, and stability at high speeds have been improved, making it suitable for practical use.

In other words, when this ship is sailing at high speed, and as it increases in speed, the center of force moves toward the stern, and even if the stern tries to lower, lift force equivalent to that force can be obtained from the rear of the lower hull. It can stabilize the ship's attitude.

Furthermore, since the maximum width of the lower hull is located at the rear, it is not only easier to arrange, assemble, and maintain the screw shaft, etc., but also it is possible to use two shafts.

In addition, even though the center of buoyancy in the longitudinal direction of the ship is located at the rear of the ship due to the structure of the struts, the center of buoyancy moves to the rear, which prevents pitching caused by up-and-down rocking, and prevention of up-and-down rocking caused by pitching. It is possible to increase the damping force of those movements. As a result, the hull can be made more stable even when sailing at high speed.

Furthermore, since the rear end of each rear strut extends rearward from the rear end of the lower hull, it is possible to prevent the water level from lowering at the stern, thereby preventing a decrease in propulsion performance and preventing the propeller from being exposed above the water surface.

Furthermore, since lifting force is obtained by widening the rear width of the lower hull, an increase in resistance can be prevented compared to the conventional example in which lifting force is obtained by attaching fins.

[Brief explanation of the drawing]

The drawing shows an embodiment of the semi-submersible multihull of the present invention,
Figure 1 is its overall side view, Figure 2 is its front view in half section, Figure 3 is a plan view of the lower hull, Figure 4
The figures are a sectional view taken along the line of FIG. 3, FIG. 5 is an overall side view showing another embodiment, FIG.
The figure is a sectional view taken along the line of FIG. 7, and FIG. 9 is a partial plan view of the lower hull showing a state in which the screw shafts are two axes. 1...Atsupahal, 2...Lower hull, 3,
4...Strut.

Claims (1)

[Scope of utility model registration request] In a semi-submersible multihull in which an upper hull and a plurality of lower hulls arranged below the upper hull are connected by struts, the rear end of each rear strut is positioned rearward from the rear end of the lower hull. A semi-submerged structure in which the lower hull is extended, and the lower hull is flattened, and the width of the lower hull is located at the rear of the lower hull, and the width from the front end of the lower hull to the maximum width gradually becomes wider toward the rear. type multihull.