JP3310846B2 - Floating breakwater using tanker - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a floating breakwater using a tanker, which is obtained by modifying a large-sized tanker so as to maintain sufficient wave-breaking performance against long-wave waves in the open sea.

[0002]

BACKGROUND ART Construction of large-scale artificial islands is being promoted as one of the effective uses of marine space in coastal areas. However, these artificial islands are compared with conventional artificial islands.
Since it will be constructed more offshore in the sea area affected by the waves of the open sea, it is necessary to create a temporary calm sea area to secure the operation rate of the construction work boat. Depending on the means of creating this calm sea area, the construction method of artificial islands will change,
There is an urgent need to develop a means of creating a calm sea area that is economical as a whole.

[0003] A floating breakwater is suitable as such a temporary calm sea area creating means in consideration of the mobility after construction and the economic efficiency of reuse at a different water depth. A considerable amount of floating breakwater is needed to extinguish long-period waves in the open sea, so it is economically disadvantaged to build a new one. Double hulls (double hull structure) will be required for the purpose, and the excess used conventional VLCC (Very Lar)
It is very economical if ge Crude carrier is used as a breakwater.

[0004]

Incidentally, the hull shape of the tanker is a simple box-shaped structure, so that it is not always excellent in terms of wave breaking performance. That is, in order to more effectively eliminate long-period waves in the open sea, it is necessary to improve the wave-elimination performance correspondingly. SUMMARY OF THE INVENTION It is an object of the present invention to provide a tanker-based floating breakwater that is capable of sufficiently exhibiting a wave-breaking function even in long-period waves in the open sea by using a modified tanker hull.

[0005]

In order to achieve the above object, a floating breakwater using a tanker according to the present invention comprises a plurality of center tanks formed by left and right vertical partition walls and a plurality of horizontal partition walls which partition the inside of a hull. And a plurality of side tanks , the water in the side tanks has a water column vibration.
In order to perform all vertical movements, a bottom opening communicating with outside water is provided at the bottom of the side tank, and an upper opening communicating with the outside air is provided at an upper part of the side tank. The wave-breaking performance of the floating breakwater is such that the incident wave moves the levee body to some extent, and the phase of the wave generated by the movement is shifted from the phase of the wave passing through the levee body, thereby canceling the transmitted wave. Obtained by extinguishing

[0006] In the tanker use浮消wave crest of the present invention described above, water in the water side tank which has flowed from the bottom opening
The vertical motion as column vibration becomes large near the natural period of the motion, and coupled with the motion of the hull, the phase of the hull motion is shifted from the phase of the wave, so the wave generated by the hull motion Is offset from the phase of the wave transmitted through the hull, thereby canceling the wave. Further, when water flows into and out of the side tank through the bottom opening, friction and vortex are generated in the tank and the bottom opening, so that the energy of the wave is also consumed and the wave breaking action is performed . Contact name with the and out of the outer water in the bottom opening, the outside air and out is performed by the upper opening for its replacement.

The above-mentioned bottom opening and upper opening may be formed only in the side tank on one side of the tanker. In this case, the hull of the hull is positioned so that the side tank with the opening is located on the arrival side of the waves incident on the hull. that the mooring is carried out
With this, the above-described wave canceling action can be performed. In addition, the bottom opening and the top opening described above may be formed in a center tank, in which case the water column vibrates in the center tank.
By performing the vertical movement as described above , excellent wave canceling performance can be obtained even in the region of a considerably long wavelength of the incident wave.

Further, the floating breakwater using a tanker of the present invention has a plurality of ballast tanks for restoring the horizontal and vertical inclinations of the hull, and the initial attitude of the hull is adjusted by discharging and discharging ballast water in the tanks. The ballast pump is equipped. This makes it possible to appropriately adjust the initial attitude of the hull when external water enters the side tank or the center tank through the bottom opening, that is, the inclination of the hull when there is no incident wave. Further, a weight moving means for adjusting the initial attitude of the hull may be provided. In this case, the initial tilt of the hull can be easily corrected by adjusting the position of the weight on the boat.

Further, the floating breakwater using a tanker according to the present invention is characterized in that the bottom opening and the upper opening are provided with opening and closing means, respectively. As a result, the bottom opening and the top opening of the required side tank or center tank are opened , and the water column vibrates in the tank.
By performing all the vertical movements, it is possible to adjust so as to maintain the desired wave canceling performance.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a plan view at the bottom of a tanker-based floating breakwater as a first embodiment of the present invention.
FIG. 3 is a cross-sectional view of the tank of the floating breakwater of FIG. 1,
FIG. 3 is a graph showing the wave-breaking performance curves of the floating breakwater of FIGS. 1 and 2 in comparison with the case of the original hull.

As shown in FIGS. 1 and 2, in the first embodiment, a large number of center tanks 1 and side tanks are formed by left and right vertical partition walls 6 and 6 and a large number of horizontal partition walls 7 which partition the inside of the hull 3. The used large tanker formed with No. 2 is used as a floating breakwater by being modified as follows. That is, only one side tank 2 on which the incident wave arrives is provided with a bottom opening 8 at the bottom of the side tank 2 for communicating outside water to the bottom shell 5, and an upper portion of the side tank 2 is communicated with outside air. An upper opening 9 is provided. Such a large tanker is moored as a floating breakwater by a suitable mooring means such as a sinker with a cable in a sea area where quietness is required.

In the large tanker shown in FIGS. 1 and 2, when external water enters only one side tank 2 through the bottom opening 8, the hull 3 is inclined sideways in the initial state. 2 is used as a ballast tank, and a ballast pump (not shown) for adjusting the initial posture of the hull 3 so as not to be accompanied by a lateral inclination by discharging and discharging the ballast water in the tank is provided. The ballast pump also performs an operation of adjusting the initial posture of the hull 3 so as not to be accompanied by a vertical inclination by discharging and discharging ballast water in the center tank 1 on the bow side and the stern side.

When the above-mentioned large tanker is used as a floating breakwater, the water in the side tank 2 having the bottom opening 8 and the upper opening 9 moves up and down as a water column vibration with the arrival of the incident wave. , The motion has a natural period. Therefore, if a wave having a wave period near the natural period is incident, the water column vibration increases, and the motion of the hull alone is coupled, and the phase of the coupled motion is shifted from the phase of the wave. . As a result, the wave generated by the coupled motion of the hull 3 accompanied by the water column vibration and the wave transmitted through the hull 3 cancel each other out, and thus high wave elimination performance can be obtained.

Also, when the water that has entered the side tank 2 through the bottom opening 8 through the bottom opening 8 moves up and down, the water enters and exits through the bottom opening 8, thereby reducing the wave energy. Since the part is dissipated as energy of friction and vortex, this action also contributes to the improvement of the wave breaking performance. In addition, the inflow and outflow of outside water at the bottom opening 8
As a result, outside air enters and exits through the upper opening 9 due to the replacement.
Done.

FIG. 3 shows the results of a water tank test on the wave elimination performance in the case of the first embodiment described above in comparison with the case where the hull 3 is not modified (original ship type). This is a test result in a regular wave. The vertical axis indicates transmittance (transmitted wave height / incident wave height), and the horizontal axis indicates the ratio between the wavelength of the incident wave and the ship width. The transmittance of the present embodiment shows a value smaller than the transmittance of the original ship type, and it can be seen that the wave canceling performance is improved. Also, in the case of the present embodiment, the incident wave has a width of 4 mm.
The wave canceling performance is improved up to the case where the wavelength is about 5 times. In the case of a large tanker, the ship width is about 50m,
It shows good wave-cancelling performance for a very long wave having a wavelength of 225 m (wave period 12 seconds). In this way,
According to the first embodiment, a used tanker can be used to obtain a wave-eliminating effect on long-wavelength incident waves in the open sea, and a calm sea area can be created accurately.

Next, a description will be given of a floating breakwater using a tanker according to a second embodiment of the present invention. FIG. 4 is a plan view of the bottom of the floating breakwater, and FIG. FIGS. 6 and 7 are graphs showing the breaking performance curves of the floating breakwaters of FIGS. 4 and 5 in comparison with the case of the original hull.
As shown in FIGS. 4 and 5, also in the second embodiment, the interior of the hull 3 as a levee body has a large number of center tanks 1 and side tanks 2 formed by left and right vertical partition walls 6 and 6 and a large number of horizontal partition walls 7. Is divided into The used large tanker is used as a floating breakwater by being modified as follows.

That is, only the center tank 1 is provided at its bottom with a bottom opening 10 communicating with outside water, and at the top of the center tank 1 is provided an upper opening 11 communicating with outside air. . When such a large tanker is moored as a floating breakwater as in the first embodiment described above, the same considerations as described above are applied. Also in the case of the second embodiment, the external water that has entered the tank 1 through the bottom opening 10 of the center tank 1 performs vertical water column vibration similar to that of the first embodiment, and the same A wave action is performed, and the wave elimination characteristic is in an aspect as shown in FIG.

That is, FIG. 6 shows the results of a water tank test on the wave breaking performance of the present embodiment in comparison with the case of the original hull, and shows the results of the second embodiment as in the case of the first embodiment. The transmittance also shows a value smaller than the transmittance in the case of the original hull, but in the second embodiment, compared to the first embodiment.
(Wavelength / ship width) = around 4 , that is, the incident wave
It shows remarkably high wave-cancelling performance even in a long wavelength region .

Next, a description will be given of a floating breakwater using a tanker according to a third embodiment of the present invention. FIG. 7 is a cross-sectional view of the tank portion, and FIG. The same reference numerals as those in indicate the same parts. In the third embodiment, the bottom openings 8, 10
And lids 8 as opening / closing means in the upper openings 9 and 11, respectively.
a, 9a, 10a, and 11a are provided so that only required bottom and top openings are opened, so that desired wave-cancelling performance can be obtained.

FIG. 8 shows a case where a weight moving means for adjusting the initial attitude of the hull by moving the weight is provided in each of the above-described embodiments, and the upper deck 4 of the hull 3 is shown.
In this case, tracks (tracks) 12 and 13 are formed in the ship width direction and the ship length direction, respectively, and weights 12a and 13a are provided along the tracks so as to be movable via appropriate friction reducing members such as rollers. I have. And each weight 12a, 13
A gripping means for fixing a at a required position is provided. Thus, the weights 12a and 13a can be appropriately moved to adjust the initial attitude of the hull to a state without inclination.

[0021]

As described in detail above, according to the floating breakwater using a tanker of the present invention, the following effects can be obtained. (1) Appropriately remodeling used tankers will enable long-wavelength incident waves in the open sea to be efficiently eliminated, making it easy to create a calm sea area. (2) Vertical motion as water column vibration of water in the side tank or center tank flowing from the bottom opening becomes large near the natural period of the motion, and is coupled with the motion of the hull, and Since the phase of the hull movement is shifted, the wave generated by the hull movement and the phase of the incident wave transmitted through the hull are offset and offset, and water enters and exits the side tank through the bottom opening. In addition, friction and vortices are generated in the tank and at the bottom opening, which also consumes the energy of the waves, so that high wave-elimination performance can be obtained. (3) As the outside water flows in and out of the bottom opening, outside air flows in and out of the upper opening, and the wave-dissipating function can be performed without any trouble by this replacement action. (4) The above-mentioned bottom opening and upper opening may be formed only in the side tank on one side of the tanker, and in this case, the hull of the hull is positioned so that the open side tank is located on the arrival side of the waves incident on the hull. Mooring is performed, and sufficient wave-absorbing performance is obtained. (5) When equipped with a plurality of ballast tanks for restoring the horizontal and vertical inclination of the hull, and equipped with a ballast pump that adjusts the initial attitude of the hull by injecting and discharging ballast water in the tanks, the side tank or center The initial attitude of the hull when external water enters the tank through the bottom opening can be properly adjusted and restored. (6) Weight moving means may be provided to adjust the initial attitude of the hull. In this case, the initial tilt of the hull can be easily corrected by adjusting the position of the weight on the boat. (7) If the bottom opening and the top opening are provided with opening and closing means, respectively, the bottom opening and the top opening in the required side tank or center tank are opened, and the tank is opened .
Vertical motion as water column vibration
Thus, the adjustment can be performed so as to maintain the desired wave canceling performance.

[Brief description of the drawings]

FIG. 1 is a plan view at the bottom of a tanker-based floating breakwater according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view of a tank portion of the floating breakwater of FIG. 1;

FIG. 3 is a graph showing a breaking performance curve of the floating breakwater of FIGS. 1 and 2 in comparison with a case where the original hull remains as it is.

FIG. 4 is a plan view at the bottom of a tanker-based floating breakwater according to a second embodiment of the present invention.

FIG. 5 is a cross-sectional view of the tank of the floating breakwater of FIG. 4;

FIG. 6 is a graph showing the wave-breaking performance curves of the floating breakwater of FIGS.

FIG. 7 is a cross-sectional view of a tank portion of a tanker-based floating breakwater according to a third embodiment of the present invention.

FIG. 8 is a plan view showing a case where a weight moving means is provided on an upper deck of a hull in each embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Center tank 2 Side tank 3 Hull 4 Upper deck 5 Outer shell 6 Vertical partition 7 Horizontal partition 8 Bottom opening 8a Cover 9 Top opening 9a Cover 10 Bottom opening 10a Cover 11 Top opening 11a Cover 12 Truck (track) 12a Heavy Weight 13 Track (track) 13a Weight

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hideo Kudo 2-9-7 Yaesu, Chuo-ku, Tokyo Ishiko Building Japan Work Boat Association (72) Inventor Kunihiro Ikegami 5-717-1 Fukahoricho, Nagasaki-shi No. Mitsubishi Heavy Industries, Ltd. Nagasaki Research Laboratory (72) Inventor Eisuke Sato 5, Yonbancho, Chiyoda-ku, Tokyo Toa Construction Industry Co., Ltd. (56) References JP-A-2-24288 (JP, A) JP-A-6 -293292 (JP, A) Fully open 1988-141223 (JP, U) Fully open 1984-59-217 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) E02B 3/06 B63B 39/00

Claims (6)

(57) [Claims] 1. A right and left longitudinal bulkheads and a plurality of transverse bulkheads and the tanker which is formed a plurality of center tanks and a plurality of side tanks for partitioning the interior hull, the rhino
The water in the tank makes vertical motion as water column vibration.
A floating breakwater using a tanker, characterized in that a bottom opening communicating with outside water is provided at a bottom portion of the side tank and an upper opening communicating with outside air is provided at an upper portion of the side tank. 2. The floating breakwater using a tanker according to claim 1, wherein the bottom opening and the upper opening are provided only in one side tank. 3. The left and right longitudinal bulkheads and a plurality of transverse bulkheads and the tanker which is formed a plurality of center tanks and a plurality of side tanks for partitioning the interior hull, the sensor
The water in the water tank moves up and down as water column vibration.
A floating breakwater using a tanker, wherein a bottom opening communicating with outside water is provided at the bottom of the center tank, and an upper opening communicating with outside air is provided at the top of the center tank. . 4. The floating breakwater using a tanker according to any one of claims 1 to 3, further comprising a plurality of ballast tanks for restoring the horizontal and vertical inclinations of the hull, and ballast water in the tanks. A floating breakwater using a tanker, which is equipped with a ballast pump that adjusts the initial attitude of the hull by injecting and discharging the hull. 5. The floating breakwater using a tanker according to any one of claims 1 to 4, further comprising a weight moving means for adjusting an initial attitude of the hull by moving the weight. Characterized by a floating breakwater using tankers. 6. The tanker-based floating breakwater according to claim 1, wherein opening and closing means are provided at the bottom opening and the upper opening, respectively. Breakwater.