JPS6225555B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention involves mooring the lower end of a buoy rod 1 to a sinker 3 to be sunk to the seabed using a short flexible mooring device 2.
In a type of buoy (buoy) in which the buoyant body 4 attached to the buoy rod 1 is constantly fully submerged in the water, the buoyancy of the buoy is made strong, and the buoyant body 4 is always biased upward in an upright direction. It determines what depth and size are optimal in terms of performance and economy.

Buoys and observation buoy lights that mark navigational aids or construction areas at sea must have high visibility, that the equipment installed, such as lights 5, their power supplies, and electrical wiring, are operating accurately, and that the mooring points It is required to minimize the swing around A, and to minimize the change in buoyancy and impact force applied to the moored part due to the influence of waves, and in order to satisfy these conditions, the buoy should be It is preferable to make the slope as small as possible and to make the mooring device 2 as short as possible.

In addition, even if the above slope is small, if it oscillates in a short period, it will not only impair the visibility effect but also lead to equipment failure, so the oscillation period should be as gentle as possible (in other words, the natural period should be long). It has become clear that the format described at the beginning of this book satisfies the above conditions.

However, the essential structural requirement for this new type of buoy is to make the distance between the sinking weight 3 and the lower end of the buoy rod 1 as short as possible. Of course, the shortest possible method is to use a flexible mooring device such as a shaft or a universal joint to the sinker, and if a chain is used to facilitate depth adjustment at the time of laying, a short mooring line may be used. In other words, the release due to mooring lines can be ignored. Including the above, it is called a flexible short mooring device.

The buoyant body 4 must be installed below the sea surface, and its buoyancy must be greater than the weight of the buoy itself.The light 5 must be located at a predetermined height above the seawater and in a place where it will not be exposed to seawater. The problem with realizing this buoy is that performance differs depending on the depth and size of the buoyant body 4 from the sea surface.
There is also a big difference economically.

The present invention has investigated these problems and defined their scope, and embodiments thereof will be described with reference to the accompanying drawings.

The buoy receives an external force from the waves, and a moment of resistance is generated around the mooring point A, which causes the buoy to tilt.

If this moment of resistance is M _W , M _W is expressed by the following equation.

M _W =∫D _x P _x xcosθdx ………(1) where, x: Distance from mooring point A to infinitesimal distance dx of any point in the vertical direction θ: Inclination angle of buoy rod 1 P _x : Any arbitrary point Wave pressure D _x per unit area at point x: Diameter of buoyancy body 4 at arbitrary point x On the other hand, the buoyancy of buoyancy body 4 has the ability to restore the buoy.

The righting moment generated around mooring point A is M _r
Then, M _r is expressed by the following formula.

M _r = (Pl _P - Wl _W ) sin θ (2) where, P: Buoyant force of the buoyant body 4 l _P : Distance from mooring point A to the center of the buoyant body 4 W: Self-weight of the buoy l _W : The distance from the mooring point A to the center of weight of the entire buoy The resistance moment M _W and the righting moment M _r change depending on the position of the buoyant body 4.

In other words, when the buoyant body 4 is installed as high as possible from the mooring point A (close to the water surface), l _P and l _W on the right side of equation (2) will increase, but the rate of increase of l _P will be lower than l _W Since M r is larger than that of M r , M _r increases.

However, the molecular velocity of the waves increases as the wave approaches the water surface, and the moment of resistance M _W that the buoyant body 4 receives also increases, resulting in an undesirable increase in the inclination angle θ.

Furthermore, when the buoyant body 4 is installed close to the mooring point A, the buoyant body 4 is less affected by waves, and the resistance moment M _W becomes small, but the righting moment M _r also becomes small. This results in increasing the inclination angle θ, which is also not appropriate.

In order to make the buoy less shaken, more stable, and more economical, the buoyancy body 4 is provided at a position where the resistance moment M _W is small and the righting moment M _r is large. Good.

Therefore, the applicant has 10 meters, 20 meters, 30 meters
When this type of buoy is applied at each water depth equivalent to a meter, the mounting position of the buoyancy body 4 is arbitrarily changed, and the oscillation and inclination angle θ are experimentally measured in each case, and the results are examined and analyzed. X/ as shown in Figure 2 as an average value of
A H- _lb / _ld curve was obtained.

As shown in Figure 1, X is the departure distance of the lighting section,
l _b indicates the distance from the average water surface WL to the upper surface of the buoyant body 4, and l _d indicates the distance from the average water surface WL to the mooring point A.

As can be seen in Figure 2, when l _b /l _d exceeds 0.5, X/H suddenly increases, and when it is less than 0.15, X/H increases rapidly, and between 0.15 and 0.50 is the wave height. It can be seen that the ratio of the departure distance to the distance is within a relatively small range and is relatively stable.

Therefore, it is optimal to install the buoyancy body 4 within the following range.

0.15l _d ≦l _b ≦0.50l _d ………(3) In addition, if the top surface of the buoyant body 4 is not at least 1/10 of the wave height H below the bottom of the wave, the flow of water molecules will become a vortex. It can be seen that the resistance increases rapidly.

As a result, the attachment position of the buoyant body 4 to the buoy rod 1 requires the following conditions.

l _b ≧0.6H ......(4) It is possible to install the buoyant body 4 outside the range of equations (3) and (4) to reduce the buoy's movement and inclination angle θ, but in this case, In this case, it is necessary to increase the size of the buoyant body 4, which is undesirable because it requires unnecessary manufacturing and installation costs.

Next, whether the buoy satisfies the required performance and is economical is determined based on the P/W value.

Here, W: Weight of the buoy P: Buoyant force of the buoyant body 4 The size (buoyancy) of the buoyant body 4 was arbitrarily changed for the mounting position of each buoyant body, and the departure distance X with respect to the wave height H was examined for each case. As a result, an increase rate curve of the total weight of the buoy (hereinafter referred to as the total weight of the buoy) including the X/H-P/W and P/W-mooring devices and sinkers shown in FIG. 3 was obtained.

As can be seen from this, the desirable range is 1.6≦P/W≦2.5.

In other words, when the P/W is at the end of this range, the total weight of the buoy including the mooring device and sinker 3 becomes lighter, as can be seen from Figure 3, and due to this, the material cost of the buoy itself, the mooring device, and the sinker are reduced. Although the weight of the weight can be reduced and costs are reduced as a result, the swing of the buoy and the angle of inclination θ increase rapidly. Moreover, if this range is exceeded, the total weight of the buoy becomes heavier, which increases the material cost of the buoy itself, the weight of the mooring equipment, and the weight of the sinker. The inclination angle θ does not decrease, and both are unfavorable.

In this way, the buoyant force P of the buoyant body 4, the own weight W of the buoy
There is a close relationship between the total weight of the buoy and the total weight of the buoy, and increases and decreases in these weights have a large impact on the material costs of the buoy, mooring equipment, sinkers, etc.
As a result, the cost will be increased. Therefore, P/W
It is desirable that the value of is within the above range.

Since the retractable mooring type rod-shaped buoy of the present invention has limitations on the requirements as described in the claims,
Compared to conventional types, the buoy is less affected by waves and can float in a stable state, resulting in a remarkable visual effect of the lights and a high-performance retractable mooring rod-shaped buoy at a low cost. There is an effect that can be provided.

[Brief explanation of the drawing]

The drawings show an embodiment of the retractable mooring type rod-shaped buoy according to the present invention. Fig. 1 is an elevational view showing the state of use, and Fig. 2 shows the length from the water surface to the mooring point and the distance from the water surface to the top surface of the buoyant body. A graph showing the relationship between the length ratio and the ratio of the buoy's departure distance to the wave height. It is a graph showing the relationship with the increase rate of total weight. 1...Buoy rod, 2...Mooring device, 3...Sinking weight, 4
...a buoyant body.

Claims (1)

[Scope of Claims] 1. A buoyant body having a buoyant body in the middle of a buoy rod and a mooring ring at the lower end of the buoy rod, and mooring the mooring ring and sinker with a short flexible mooring device. In a retractable mooring type rod-shaped buoy that is fully submerged in water and stands upright in the water due to buoyancy so that the water line is halfway to the buoy rod above the buoyant body, the distance from the water surface to the top surface of the buoyant body is l. _b , the distance from the water surface to the mooring point A is l _d , the wave height at the installation point is H, the weight of the buoy is W, and the buoyancy of the buoyant body is P, then the retraction mooring is such that the following three equations are satisfied. Type rod-shaped buoy. 0.15l _d ≦l _b ≦0.50l _d ………(1) l _b ≧0.6H ………(2) 1.6W≦P≦2.5W ………(3)