JPS6013879B2 - disc-shaped buoy - Google Patents

Description

[Detailed Description of the Invention] Disc-shaped buoys are normally used as large marker buoys or observation buoys for meteorological and oceanographic phenomena, etc., but in stormy weather, unexpectedly excessive force and overturning moment are applied due to waves, causing them to capsize and be washed away. There have been accidents such as this.

This invention is based on a disk-shaped buoy moored by a mooring element.
To provide a disk-shaped buoy which has a large restoring force against an overturning moment, improves wave riding, deflects wave force, prevents a floating body from overturning, reduces the force applied to a mooring element and sinker, and prevents a washout accident.

In the conventional disk-shaped buoy, the mooring ring 4 is attached to the center of the bottom surface of the floating body 1, as shown in FIG. During stormy weather, waves move in a complicated manner, but when the buoy is at the maximum slope of a large wave (swell) as shown in Figure 2, the floating body is at the breaking wave 8 or 4/wave 9, and the wave force is When F is applied and at the same time strong wind pressure is applied to the turret as shown by arrow F', resulting in an overturning moment, even a disc-shaped buoy with large reserve buoyancy and restoring force may capsize.

In addition, disc-shaped buoys generally have a large reserve buoyancy, that is, a large buoyancy per unit of water, and a large force is applied to the mooring element due to vertical movement due to waves.

Particularly in relatively shallow waters, if the departure distance is to be shortened to a certain extent, a large mooring force is required and the sinker becomes large. In addition, in shallow water, the wave height relative to the wavelength is high, while the mooring elements are relatively short, leaving little room for the cable to move up and down.Since the cable is moored at the center of the bottom of the buoy, the cable is subject to vertical movement of the floating body due to waves and excessive tension due to large buoyancy. The force and the impact force caused by the punching of the bottom of the floating body by waves are added together, creating an unexpectedly excessive tension that may eventually break the mooring element.

As a countermeasure against these problems, in the present invention, as shown in FIG. 3, the mooring ring 4 is mounted eccentrically by lp from the center of the floating body.

Next, the present invention will be explained in detail.

Figure 1 shows a secondary disc-shaped buoy. 1' is a disc-shaped floating body, 2 is a turret, 3 is a light fixture, 4 is a mooring ring attached to the center of the bottom of floating body 1, and 5 is a buoy on the secondary weight 6. It is a mooring element for mooring.

Figure 3a shows the situation in still water without wind waves and currents.

In this case, there is no lateral external force acting on the buoy, and the weight of the mooring element (mainly the chain) in the water is the mooring force Po.
In order to prevent the floating body from tilting due to this, water ballast is used as a ballast device for tilt adjustment? or solid ballast (not shown)
is piled eccentrically on the opposite side of the attachment position of the mooring ring 4, and the point of action (G) of the resultant force of the mooring force Po in still water and the weight (W) of the floating body
′) is on the center line of the floating body, and the deck is kept horizontal in still water. Therefore, the center of gravity G of the floating body is shifted by one point from the center of the floating body to the side opposite to the mooring ring, as shown in Figure 3a.

Therefore, the following formula holds. W×1g=P.

×1p...'11 Next, in the case of large waves in stormy weather and strong winds that would capsize a disc-shaped buoy, the greatest risk of capsizing is, as mentioned above, the largest slope on the lee side of the large waves. Figure 3b shows this situation. The position of the water surface changes to W'L',
The floating body is 8 with respect to the wave surface W'L', and the center of the forehead diagonal buoyancy moves to B', which is lf apart from the center line of the floating body. At this time floating heart 8
It is assumed that a buoyant force Fb acts on the mooring ring 4, and a lateral force Ft due to wind and waves acts on a position lt apart from the mooring ring 4 as shown in the figure. The buoy tries to drift away due to this lateral force Ft, but since it is moored to the sinker by the mooring element, the buoy becomes tense, and the mooring force P moves towards the mooring element 5 as shown in the figure. work. The horizontal component Ph of this mooring force P is balanced with the above-mentioned lateral force Ft, and is equal in magnitude to Ft and opposite in direction. Also, the vertical component Pn of the mooring force P is the weight P of the cable itself in the water. larger than Pn=P.

10△P ……'21, then △P
is the increase due to the holding force (mooring force) of the weight. At this time, looking at the balance of the rotational moment around point 〇, we find that Fh
Also fCOS81 10Ftlt 10Wigcos81Pnlpcos8=0Here, 8; Reflection angle of the center line of the floating body with the vertical line, {1}, '2) If you apply the formula to the above formula and simplify it, Fb× lfcoS8
,=△P1pcos8-Ftlt...'31
Separately, the restoring force moment due to the buoy tilting 0 from the wave surface (W'L') is equal to the difference between the moment due to the mooring force of the mooring element △P and the moment due to the lateral force Ft. The floating body will be balanced (with respect to W'L) by tilting by the forehead oblique angle (8,).

In other words, if △Pipcos8>Ftlt, the floating body is tilted clockwise with respect to the wave surface as shown in Figure 3b, and △P1p
If cosa<Ftit, the floating body is aligned with the wave surface (W'L') in all directions.

In any case, by making the mooring ring 4 eccentric by lp from the center of the floating body, the overturning moment is reduced by ΔPlpcos8. In such a situation, if breaking waves or small waves as shown in Figure 2 come and further wave force F is applied, a moment will be applied to capsize in the counterclockwise direction, but the
The mooring force increases further on the mooring ring, and the vertical component of that increase is △? Therefore, by mooring with an eccentric mooring ring, the overturning moment is reduced by (△P+△P)] pcosa, and capsizing is avoided.

In addition, because the mooring ring is installed eccentrically, when the mooring force becomes excessive in rough weather, the floating body will be rotated clockwise by the moment of △P1pcos8, and the tip of the floating body will be pinched, causing waves against the bottom of the floating body. Punching, etc. of the mooring element can be avoided, and breakage and outflow of the mooring element can be reduced.

In addition, by eccentrically positioning the mooring ring, the direction of the buoy remains constant.
The mooring element will not be twisted.

Figures 4 and 6 show another embodiment of the present invention. In Figure 4, the mooring rings are installed eccentrically by two points to the left and right to adjust the direction of the buoy with respect to the water flow. What I had more.
In Fig. 5, two mooring rings are attached at the front and rear, and a chain is passed around the mooring ring, and a mooring element is attached to this with a shirtcle, so that the degree of eccentricity can be adjusted.

[Brief explanation of the drawing]

Fig. 1 is a front view showing a secondary disc-shaped buoy, Fig. 2 is a front view showing the state of the buoy at the maximum slope of a large wave, and Figs. 3a and 3b are examples of an embodiment of the present invention. FIG. 4 is a front and bottom view of another embodiment of the present invention, and FIG. 5 is a front view of another embodiment of the present invention. Kawama disk-shaped floating body, 2 is a turret, 3 is a light fixture, 4' is a mooring ring,
5 is a mooring element, 6 is a sinker, 7' is a water ballast, 8 is a breaking wave,
9 is a small wave. Tsutomu! Figure 2 Figure 2 Younger brother Kodaku Poverty 1 Illusion Figure 4 Figure 5

Claims (1)

[Claims] 1. In a disc-shaped buoy that has a mooring ring on the bottom plate that is moored to a sinker, the mooring ring is installed eccentrically from the center, and the ballast is eccentrically stacked on the opposite side of the mooring ring attachment position, and the mooring force in still water and the floating body are A disc-shaped buoy characterized by having a ballast device for adjusting inclination so that the point of action of the resultant force of weight is on the center line of the floating body and the deck of the buoy is kept horizontal in still water.