JPS5833033Y2 - semi-submersible catamaran - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a semi-submersible catamaran having a pair of left and right lower bodies below the water surface connected to an upper hull above the water surface via struts.

Conventional semi-submersible catamarans of this type include those shown in Figs. A propulsion device 1a is provided, and a support 2 with a small waterline width is erected above each lower fuselage 1.

There are two types of struts 2: one that is provided integrally over almost the entire length of the lower fuselage 1, and the other that is divided into front and rear parts.

An upper hull 3 connecting the twin-hulled lower fuselage 1 is provided at the upper end of each strut 2.

When a ship like this, with a small waterline area of the struts 2 and a relatively large lower fuselage 1, sails, a bow-down moment acts at relatively low speeds as shown in Figure 4, and this moment increases with the ship speed. However, when the speed exceeds a certain level, this bow-down moment begins to decrease, and around the design speed, a bow-up moment acts on the ship.

This hull shape has a small waterline area and low vertical stability, so
The above moment causes a large vertical heel, jeopardizing the safety of the vessel.

Therefore, conventionally, in order to control the attitude of the ship, hydrofoils 4
is installed on the lower fuselage 1 below the water surface 5, but since the magnitude and direction of the heeling moment acting on the hull differ depending on the ship speed, the angle of attack of the hydrofoil 4 is adjusted according to each ship speed. need to be controlled.

By the way, it is possible to manually adjust the angle of attack of the hydrofoil 4 by remote control from the bridge while observing the ship's speed or attitude angle, but this is a complicated process that is not required for normal ship operation. This will add additional operations.

Furthermore, although automatic control without manual intervention is possible considering the current technological level, it requires a large amount of cost, and especially in the case of small, semi-submerged ships, it accounts for a large proportion of the overall construction cost. (This results in a loss of economic efficiency.

This type of small-waterline catamaran is a type of ship that could originally be established as a high-speed ship, but because it is a high-speed ship, failure of the control device could be fatal.

The present invention aims to solve these problems, and does not require special control of the hydrofoils as in the past, but automatically responds to changes in the attitude angle of the ship. The purpose of the present invention is to provide a semi-submersible catamaran that is equipped with righting wings that change the submerged area and has improved safety and reliability.

For this reason, the semi-submersible catamaran of the present invention has an upper hull above the water surface and a pair of left and right lower fuselages below the water surface that are connected to the upper hull via struts. In between, multiple stages of front righting wings are arranged near the bow section, symmetrically with respect to the hull center plane, and at appropriate intervals above and below the designed waterline, and near the stern section, front righting wings are arranged symmetrically with respect to the hull center plane. A rear righting wing is arranged symmetrically with respect to the plane and inclined so as to intersect diagonally with the planned waterline,
The present invention is characterized in that a longitudinal stabilization mechanism for the sailing attitude of the ship body is formed by the plurality of stages of front righting wings near the bow and the inclined rear righting wings near the stern.

First, the principle of the present invention will be described with reference to explanatory drawings of the catamaran. Fig. 5 is a longitudinal cross-sectional view thereof, and Fig. 6 is a front view thereof. An upper hull 3 above the water surface is provided to the pair of lower fuselages 1, 1 via struts 2. Between the left and right lower fuselages 1, 1, the hull center is located near the bow and near the stern, respectively. Hydrofoil 10a tilts symmetrically with respect to plane C and diagonally intersects with planned waterline 5p.

10b, and the structure is such that the area of the submerged portion of the wing increases as the draft at that point increases.

FIGS. 5 and 6 show, as an example of such a hydrofoil, a hydrofoil that is inclined so as to obliquely intersect the planned waterline 5p.

Then, A is the projected area of the submerged hydrofoil 10 a t 10 b on the x-y plane.

The amount of increase due to the sinking of 1tAO29 units is C1, C2
: Hydrofoil 10a.

The angle (angle of attack) between the center line of the cross-sectional shape parallel to the x-z plane of 10b and the X axis is ctl, σ2; represents the change in the lift coefficient with respect to the change in the angle of attack. Let's write the X coordinates as Xl and X2.

Consider the case where the ship is traveling at speed V in this state, and if the force (lift force) in the z direction on each hydrofoil is Fl, then Fs = 4V2Ao 1cLdl ctl (i = 1
? 2)-=(1).

Next, the ship moves α from this state in the direction of lowering the bow and raising the stern.
Suppose it is tilted slightly.

In that case, AOI″AO1+ CI
″″1−, so if the force in two directions is F′1, then F′1=−ρV2(Ao 1+c1X10CLd 1
(α1−α)・・・・・・・・・(2)

If the amount of change in Fl is written as JF, then JF=ρV2CLdl(C
IXIα2-(C1xlαt Aot)α) ・・
......(3).

Since it is necessary for the action of these hydrofoils that the JF obtained in this way acts in the direction of restoring the displacement of each hydrofoil with respect to the water surface, the condition, that is, xt
In the hydrofoil 10a located at >O (bow side), jF moves in the negative direction of the two axes (the direction opposite to the X-axis arrow), and in the hydrofoil 10b located at When we find the conditions for movement in the direction of the arrow, we find that equation (3) is satisfied and α is in the range of .

From formula (5), in the case of the hydrofoil 10b installed at Xl×O, A.

The larger 1 is, the better the operation is over a wider range of α, and in the case of the hydrofoil 10a installed at Xl>0, A.

It can be seen that the smaller the value of 1, the better.

Therefore, in a semi-submersible catamaran as an embodiment of the present invention,
As shown in FIGS. 7 to 9, the upper hull 3 above the water surface is connected to the pair of left and right lower hulls 1 and 1 below the water surface via struts 2.
A plurality of stages of front righting wings 21 are provided near the bow between the left and right lower fuselage 1.10, symmetrically with respect to the hull center plane C, and at appropriate intervals above and below the planned waterline 5p. A V-shaped rear righting wing 22 is arranged near the stern portion and is symmetrical with respect to the hull center plane C and inclined so as to diagonally intersect with the planned waterline 5p.
will be placed.

In this way, the plurality of stages of front righting tools 21 near the bow and the inclined rear righting tools 22 near the stern constitute a longitudinal stabilizing mechanism for the sailing attitude of the ship.

In other words, when the hull tilts forward due to some disturbance, the number of submerged wings of the multiple stages of front righting tools 21 increases at the bow, increasing the lift, while at the stern, the tilted rear righting force increases. Since the submerged area of the gear 22 is reduced, the lifting force is reduced, both of which act in a direction to restore the forward heel of the ship.

Furthermore, when the hull is tilted backwards, the lift force is in the opposite direction to that in the above case, and in this case as well, it acts in a direction to restore the tilted rearward position of the hull.

The rear restoring tool 22 is a continuous wing, and the front restoring tool 21 is a wing provided intermittently in a stepped manner, so the latter is more difficult than the former.

1 (the projected area of the submerged part of the wing on the By arranging the V-shaped rear restoring tool 22, it becomes easy to obtain good longitudinal stability as a whole, as described in the explanation of FIGS. 5 and 6.

In addition, each righting tool 2L22 is a fixed wing, so there is no need for control, which not only does not increase the construction cost, but also eliminates any fear of failure, so reliability with respect to safety is significantly improved.

The front righting tool 21 near the bow remains as shown in Figures 7 and 9, and the rear righting tool 22 near the stern is tilted in the opposite direction to the embodiment shown in Figure 7.8 to form an inverted V-shape. Similar effects can be obtained.

As detailed above, the semi-submersible catamaran of the present invention includes an upper hull above the water surface and a pair of left and right lower hulls below the water surface that are connected to the upper hull via struts. Between these lower fuselages, multiple stages of righting tools are arranged near the bow, symmetrically with respect to the hull center plane, and at appropriate intervals above and below the planned waterline, and near the stern. The structure is extremely simple, with a rear righting tool that is symmetrical with respect to the hull center plane and inclined so as to intersect diagonally with the planned waterline, eliminating the need for complicated control operations for conventional hydrofoils. As a result, the vertical stability of the hull is automatically ensured, which has the advantage of contributing to a significant improvement in the safety of semi-submersible catamarans.

[Brief explanation of the drawing]

Figures 1 to 3 show conventional semi-submersible catamarans.
The figure is a side view, Figure 2 is a cross-sectional view of the roll L in Figure 1,
Figure 3 is a cross-sectional view taken along the -m arrow in Figure 1, and Figure 4 is a graph showing the relationship between ship speed, bow-up moment, and bow-down moment of a normal semi-submersible catamaran. , 5th
, 6 shows a semi-submersible catamaran for explaining the principle of the present invention, FIG. 5 is its longitudinal sectional view, FIG. 6 is its front view, and FIGS. 7 to 9 are A semi-submersible catamaran as an embodiment of the present invention is shown in which FIG. 1 is a longitudinal sectional view, FIG. 8 is a rear view, and FIG. 9 is a front view. 1...Lower fuselage, 2...Strut, 3...Upper hull,
5p... Planned waterline, 21... Front righting tool, 22.
...Aft righting tool, C...Hull center plane.

Claims (1)

[Scope of utility model registration request] It has an upper hull above the water surface and a pair of lower hulls on the left and right below the water surface that are connected to the upper hull via struts. At the same time, multiple stages of front righting wings are arranged at appropriate intervals above and below the designed waterline, and near the stern, the wing is symmetrical with respect to the hull center plane and intersects diagonally with the designed waterline. A rear righting wing is arranged so as to be inclined as shown in FIG. A semi-submersible catamaran characterized by