JP7660877B2 - Floating Structure - Google Patents

Description

The present invention relates to a floating structure that floats on the water surface.

Floating structures that float on the water surface have been widely used as facilities on water in oceans, lakes, rivers, etc. (see Patent Document 1). Such floating structures do not require the installation of supports on the water bottom, making the structure simple and low-cost, but they have the problem of being affected by motion caused by waves. Therefore, there is a demand for floating structures that can suppress motion caused by waves and float stably on the water surface.

Specific examples of such floating structures include observation buoys used for marine meteorological observation, wave and tsunami observation, wind observation, seawater surveys, and environmental surveys in the fisheries and aquaculture industries (see Patent Document 2). In addition to suppressing motion caused by waves, observation buoys are desired to have a large volume that can accommodate an increased number of observation sensors and a secure power source for long-term observation. There is also a demand for highly maintainable buoys that allow maintenance of the onboard equipment to be performed at sea. There is also a demand for low-cost, simple-structure buoys that can be used for land and water transportation.

JP 2005-029065 A JP 2001-341693 A

The objective of the present invention is to provide a floating structure that can efficiently suppress rocking caused by waves and float stably on the water surface, while having a simple and compact configuration and excellent maintainability and transportability.

As a result of intensive research into solving the above problems, the inventors discovered that the above problems could be solved by configuring a float with a float body and a float convex portion protruding downward (a shape in which the lower periphery of the float is missing), and providing a motion suppression plate around the float convex portion and inward from the outer periphery of the float body, thus completing the present invention.

That is, the present invention is as follows.
[1] A floating structure that floats on the water surface,
A float including a float body whose upper surface appears above water and a float convex portion protruding downward from a lower portion of the float body;
A motion suppression plate is provided around the floating protrusion and inward from the outer circumferential surface of the floating body to suppress motion caused by waves;
A floating structure comprising:
[2] The floating structure described in [1] above, characterized in that the motion suppression plate is a horizontal plate extending in the circumferential direction and provided with a gap outward from the lower side portion of the floating convex portion.
[3] The floating structure described in [1] above, characterized in that the motion suppression plate is a vertical plate extending in the circumferential direction and spaced downward from the outer bottom of the floating body.
[4] A floating structure as described in [2] or [3] above, characterized in that the motion suppression plate is provided above the bottom surface of the floating convex portion.
[5] The floating structure according to any one of the above [1] to [4], characterized in that the floating body and the floating convex portion are each cylindrical.
[6] The floating structure according to any one of [1] to [5] above, characterized in that it is an observation buoy.

The floating structure of the present invention can efficiently suppress rocking caused by waves and float stably on the water surface, and its simple and compact structure makes it easy to maintain and transport.

1 is a schematic side cross-sectional view of a floating body structure according to a first embodiment of the present invention. FIG. FIG. 2 is a schematic cross-sectional view taken along line AA of the floating body structure according to the first embodiment shown in FIG. 1 . 1A and 1B are explanatory diagrams showing a floating structure according to a first embodiment of the present invention floating on the sea, in which FIG. 1A shows a state in which the floating structure is moored at two points, and FIG. 1B shows a state in which the floating structure is moored at one point. FIG. 5 is a schematic side cross-sectional view of a floating body structure according to a second embodiment of the present invention. FIG. 5 is a schematic end view of the floating body structure according to the second embodiment shown in FIG. 4 taken along line B-B. FIG. 11 is a schematic cross-sectional side view of a float of a floating body structure according to a third embodiment of the present invention. FIG. 11 is a schematic cross-sectional side view of a float of a floating body structure according to a fourth embodiment of the present invention. 13 is a photograph showing a floating body of a floating structure according to a fifth embodiment produced in an example. 13 is a photograph showing a floating body structure according to a fifth embodiment produced in an example, where (a) is a photograph taken obliquely from above, and (b) is a photograph taken obliquely from below. 13 is a photograph showing a floating body structure according to a sixth embodiment produced in an example, where (a) is a photograph taken obliquely from above, and (b) is a photograph taken obliquely from below. 6A and 6B are photographs showing a conventional floating structure produced in the examples, where (a) is a photograph taken obliquely from above, and (b) is a photograph taken obliquely from below. FIG. 2 is an explanatory diagram showing an outline of a vibration characteristic test. FIG. 13 is a diagram showing the results of measuring the motion characteristics of the floating structure produced in the embodiment.

The floating structure of the present invention is a floating structure that floats on the water surface, and is characterized by comprising a float having a floating body whose upper surface appears above the water and a floating protrusion that protrudes downward from the lower part of the floating body, and a motion suppression plate that is provided around the floating protrusion and inward from the outer periphery of the floating body to suppress motion caused by waves.

In this specification, the movement of a floating structure around an axis perpendicular to the direction of approaching waves is referred to as vertical sway (sway in the pitch direction), and the movement of a floating structure around an axis parallel to the direction of approaching waves is referred to as lateral sway (sway in the roll direction).

In the floating structure of the present invention, the motion suppression plate provided around the float's protruding portion provides resistance to the fluid flow at the bottom of the floating structure caused by vertical or horizontal motion due to waves, thereby suppressing motion and enabling stable floating. In addition, compared to conventional floats, the shape of the float is such that only a small portion, such as the lower periphery, is missing, so sufficient internal space can be secured and the structure can float stably. In addition, since the motion suppression plate is provided inside the outer periphery of the float body, it is compact and the risk of interference with the outside due to the motion suppression plate can be reduced. In other words, when floating on the water surface, a maintenance ship or the like can be brought close, making maintenance on the water easier. In addition, when towed by a ship or the like to move on the water surface, it can be towed smoothly without resistance. Furthermore, when loaded onto a truck or ship for transportation, it can be transported efficiently without risk of damage.

The floating structure of the present invention can be used, for example, as an observation buoy for obtaining information related to meteorology, ocean conditions, and the fishing industry, as well as a navigational buoy, a construction marker buoy, a floating pier, a barge, etc.

Methods for installing the floating structure of the present invention include multi-point mooring, which is excellent at maintaining its position against external forces such as wind, waves, and currents, and single-point mooring, which swings around to reduce the force received from external forces.

The floating structure of the present invention will be described below based on the state in which it is floating on the water surface.

[Floating body]
As described above, the float of the present invention comprises a float body and a float protruding portion provided so as to protrude downward from the lower portion of the float body. The float body and the float protruding portion usually have an internal space and are in communication with each other. This internal space has an airtight structure to prevent water from entering from the outside, and is configured to be able to accommodate various devices such as batteries for observation equipment, power generation equipment, and fuel containers, as well as weight adjustment members such as ballast and foam materials.

(Floating body)
As described above, the float body is a hollow body having an internal space, and its upper surface appears above the water when floating on the water surface. For example, observation devices such as data recorders, communication devices, weather meters, and wind condition observation devices, as well as lighting, railings, etc. are mounted on the upper surface of the float body. The observation devices, etc. are protected by a container or cover as necessary.

The shape of the float body is not particularly limited as long as it can float on the water surface, but since it will be equipped with observation equipment, etc. as described above, it is preferable for the top surface to be flat, such as a cylinder or a rectangular parallelepiped.

The material of the floating body is not particularly limited as long as it is waterproof (airtight), and examples include steel, aluminum, FRP, polyethylene resin, PC concrete, polyvinyl chloride resin, etc.

(Floating body convex part)
The float convex portion is a hollow body having an internal space, like the float body, and is provided so as to protrude downward from the bottom of the float body. Compared to conventional floats, the float of the present invention has a shape in which only a small part, such as the lower periphery of the float, is missing, so that a sufficient internal space can be secured, the float can float stably, and a large amount of equipment can be accommodated.

The shape of the float's protrusion is not particularly limited as long as it fits within the float's main body, and examples include a cylinder, a rectangular parallelepiped, an inverted truncated cone, an inverted truncated pyramid, a multi-stage cylinder, a multi-stage rectangular parallelepiped, a multi-stage truncated cone, and a multi-stage truncated inverted pyramid.

The material of the float's protrusions is not particularly limited as long as it is waterproof (airtight), and can be the same as that of the float's main body.

[Sway suppression plate]
The motion suppression plate is a member that is provided around the float convex portion and inward from the outer circumferential surface of the float main body, and suppresses motion caused by waves. The motion suppression plate provides resistance to the fluid flow at the bottom of the floating structure caused by vertical or horizontal motion caused by waves, thereby suppressing motion and enabling stable floating. "Inward from the outer circumferential surface of the float main body" means a range that does not exceed the outer circumferential surface of the float main body, and includes the same surface. By providing the motion suppression plate inward from the outer circumferential surface of the float main body, the floating structure can be made compact, and the risk of the motion suppression plate interfering with the outside can be reduced.

It is also preferable that the motion suppression plate is provided above the bottom surface of the floating body's convex portion. In other words, it is preferable that the motion suppression plate does not protrude below the bottom surface of the floating body's convex portion. This configuration makes the floating structure more compact.

In addition, it is preferable that the motion suppression plate is provided continuously around the entire circumference of the float's convex portion, but it may be provided intermittently or on a specified side (for example, only on a pair of opposing sides when the float is a rectangular parallelepiped).

The material of the motion suppression plate is not particularly limited, and may be the same as that of the floating body itself.

Specific preferred embodiments of the motion suppression plate include a horizontal plate extending in the circumferential direction and spaced outward from the lower side of the float's convex portion (see FIG. 1), and a vertical plate extending in the circumferential direction and spaced downward from the outer bottom of the float's main body (see FIG. 4). Note that the horizontal plate or vertical plate in this invention is a concept that includes a horizontal plate or vertical plate inclined within 10°, preferably within 5°, from the horizontal or vertical direction.

In the case where the motion suppression plate is a horizontal plate extending in the circumferential direction and provided with a gap outward from the lower side of the floating convex portion, the gap between the floating convex portion and the plate is, for example, about 20 to 200 mm, preferably 20 to 100 mm, more preferably 30 to 80 mm, and even more preferably 40 to 60 mm. In this case, when the floating structure sways, the water remaining around the floating convex portion flows out forcefully from the gap between the motion suppression plate and the floating convex portion, which increases the damping force that reduces the vertical or horizontal swaying, and the swaying can be suppressed. In addition, the motion suppression plate is preferably disposed in a position flush with the bottom surface of the floating convex portion. This reduces the unevenness of the surface of the floating structure and prevents damage due to external interference.

In the case where the motion suppression plate is a vertical plate extending in the circumferential direction and spaced downward from the outer bottom of the floating body, the distance from the floating body is, for example, about 20 to 200 mm, preferably 20 to 100 mm, more preferably 30 to 80 mm, and even more preferably 40 to 60 mm. In this case, as in the case where the horizontal plate is provided, the damping force that reduces the vertical or horizontal motion can be increased, and the motion can be suppressed. In addition, the motion suppression plate is preferably disposed in a position flush with the outer peripheral surface of the floating body. This reduces unevenness on the surface of the floating structure and prevents damage due to external interference.

When the floating structure of the present invention is cylindrical, the diameter of the floating body can be set appropriately depending on the application, etc., but is, for example, 0.3 to 100 m. In the case of an observation buoy, 0.5 to 15 m is preferable, 1 to 10 m is more preferable, and 2 to 5 m is even more preferable. In addition, the diameter of the floating convex part is preferably 50 to 85% of the diameter of the floating body, more preferably 60 to 80%, and even more preferably 70 to 80%.

The draft of the float can be set appropriately depending on the application, etc., but is preferably 20-100% of the diameter of the float body, more preferably 20-70%, and even more preferably 30-50%. The height of the float convex portion is preferably 20-50% of the draft of the float, more preferably 25-45%, and even more preferably 30-40%.

When the floating structure of the present invention is rectangular, the size of the floating body and the floating convex portion can be set in the same manner, with the above diameter as the diagonal length. Note that when the long side of the floating body is three times longer than the short side, the swaying around the central axis in the short side direction is small, so it is not necessarily necessary to provide motion suppression plates at both ends in the longitudinal direction.

Below, one embodiment of the floating structure of the present invention will be specifically described with reference to the drawings, but the present invention is not limited to this embodiment.

Here, FIG. 1 is a schematic side cross-sectional view of a floating structure according to a first embodiment of the present invention. FIG. 2 is a schematic cross-sectional view along line A-A of the floating structure according to the first embodiment of the present invention shown in FIG. 1. FIG. 3 is an explanatory diagram showing a state in which the floating structure according to the first embodiment of the present invention is floating on the sea, (a) shows a state in which it is moored at two points, and (b) shows a state in which it is moored at one point. FIG. 4 is a schematic side cross-sectional view of a floating structure according to a second embodiment of the present invention. FIG. 5 is a schematic end view along line B-B of the floating structure according to the second embodiment of the present invention shown in FIG. 4. It should be noted that the drawings referred to in the embodiments are schematic drawings for a deeper understanding. For example, the dimensional ratio of an object depicted in the drawing may differ from the dimensional ratio of an actual object. The white arrows in FIG. 1 and FIG. 4 represent the flow of water.

As shown in FIG. 1, a floating structure 10 according to a first embodiment of the present invention includes a floating body 12 and a motion suppression plate 14.

The float 12 comprises a float body 16, the upper surface of which is above water, and a float protrusion 18 that protrudes downward from the lower part of the float body 16.

The float body 16 is a steel cylinder with a diameter of 2 m and a height of 0.9 m. A float convex part 18 is provided at the bottom of the float body 16. The float convex part 18 is a steel cylinder with a diameter of 1.5 m and a height of 0.3 m. The float body 16 and the float convex part 18 are hollow and communicate with each other.

As shown in FIG. 2, the motion suppression plate 14 is a horizontal plate extending in the circumferential direction, provided around the float protrusion 18 and inward from the outer circumferential surface of the float body 16, with a gap 20 of about 50 mm from the lower side of the float protrusion 18 outward. The motion suppression plate 14 is connected to the outer circumferential surface of the float protrusion 18 and the bottom surface of the float body 12 by brackets 22 provided at equal intervals in the circumferential direction of the float protrusion 18.

As shown in FIG. 3, the floating structure 10 according to the first embodiment of the present invention can be used, for example, as an observation buoy floating on the sea. The inside of the floating structure 10 (inside the floating body 16 and the floating protrusion 18) can accommodate ballast and batteries for observation equipment. In addition, a container 24 that accommodates observation equipment is mounted on the upper part of the floating structure 10. When floating on the sea, a multi-point mooring method such as a two-point mooring method (FIG. 3(a)) in which the structure is moored by two mooring lines 28 connected to an anchor 26, or a single-point mooring method (FIG. 3(b)) in which the structure is moored by one mooring line 32 connected to an anchor 30 can be used.

Next, a floating structure according to a second embodiment of the present invention will be described in detail.
As shown in FIG. 4 , a floating structure 34 according to the second embodiment of the present invention includes a floating body 12 and a motion suppression plate 36 .

The float 12 has a similar configuration to the float of the floating structure according to the first embodiment described above, so it is given the same reference numeral and the description is omitted.

As shown in FIG. 5, the motion suppression plate 36 is a vertical plate extending in the circumferential direction, provided around the float protrusion 18 and inward from the outer circumferential surface of the float body 16, with a gap 38 of about 50 mm below the outer bottom of the float body 16. The motion suppression plate 36 is connected to the outer circumferential surface of the float protrusion 18 and the bottom surface of the float body 16 by brackets 40 provided at equal intervals in the circumferential direction of the float protrusion 18.

Next, floating body structures according to the third and fourth embodiments of the present invention will be described. Note that the floating body structures according to the third and fourth embodiments have the same configuration as the floating body structure 10 described above, except for the float convex portion, and therefore the same reference numerals are used and the description is omitted. In addition, the motion suppression plate is omitted for easier understanding. Here, FIG. 6 is a schematic side cross-sectional view of a float of the floating body structure according to the third embodiment of the present invention. FIG. 7 is a schematic side cross-sectional view of a float of the floating body structure according to the fourth embodiment of the present invention.

As shown in FIG. 6, in a floating structure 42 according to a third embodiment of the present invention, the floating protrusion 44 is configured as an inverted truncated cone when viewed from the side. Also, as shown in FIG. 7, in a floating structure 46 according to a fourth embodiment of the present invention, the floating protrusion 48 is configured as a stepped two-stage cylinder when viewed from the side.

[Swing characteristic test]
Example 1
A rolling characteristic test was carried out using a floating body structure according to the fifth embodiment of the present invention (Example 1). Fig. 8 is a photograph showing a floating body main body of the floating body structure according to the fifth embodiment produced in Example. Fig. 9 is a photograph showing the floating body structure according to the fifth embodiment produced in Example, where (a) is a photograph taken from diagonally above and (b) is a photograph taken from diagonally below.
The floating structures used in this test (Examples 1 and 2, Comparative Example 1) were assumed to be 1/10 scale models of actual vessels.

Specifically, the float used was a cylindrical float body made of polyvinyl chloride resin with a diameter of 0.2 m and a height of 0.09 m, and a cylindrical float convex part made of polyvinyl chloride resin with a diameter of 0.15 m and a height of 0.03 m. The draft of the float was 0.08 m. The motion suppression plate used was a horizontal plate made of polyvinyl chloride resin with a thickness of 5 mm, extending in the circumferential direction, and installed around the convex part of the float and inside the outer periphery of the float body, at a position where the bottom of the float convex part and the bottom of the motion suppression plate are flush with each other, with a gap of about 5 mm outward from the lower side of the float convex part. The outer periphery of the horizontal plate is flush with the outer periphery of the float body.

Example 2
A rolling characteristic test was carried out using the floating structure according to the sixth embodiment of the present invention (Example 2). Fig. 10 is a photograph showing the floating structure according to the sixth embodiment produced in Example, where (a) is a photograph taken from diagonally above, and (b) is a photograph taken from diagonally below.

Specifically, the float used was manufactured in the same manner as in Example 1. The motion suppression plate used was a circumferentially extending vertical plate made of polyvinyl chloride resin with a thickness of 5 mm, which was installed around the float's convex portion and inside the outer peripheral surface of the float body, at a position where the outer peripheral surface of the float body and the outer peripheral surface of the motion suppression plate were flush with each other, with a gap of about 5 mm below the outer bottom of the float body. The outer peripheral surface of the vertical plate was flush with the outer peripheral surface of the float body.

(Comparative Example 1)
A conventional floating structure (Comparative Example 1) was manufactured in which the float was a cylindrical body made of polyvinyl chloride resin with a diameter of 0.2 m and a height of 0.12 m. Figure 11 shows photographs of the conventional floating structure manufactured in the example, where (a) is a photograph taken obliquely from above and (b) is a photograph taken obliquely from below.

The vibration characteristic test was carried out under the following conditions.
As shown in Figure 12, in a marine test tank for ships measuring 60 m in length, 4 m in width, and 2.3 m in depth, a motion sensor was attached to the top of the floating structure of this embodiment, and the floating structure was moored so as not to affect its motion. Waves were generated using a wave-making device, and the pitch amplitude/wave amplitude (deg/m) of the floating structure per wave period (sec) was measured.
The results are shown in Figure 13.

As shown in Figure 13, the floating structures according to the embodiments (Examples 1 and 2) have a smaller pitch amplitude/wave amplitude at peak time (3 s) than the conventional floating structure (Comparative Example 1), and it was confirmed that they can suppress wave-induced motion and float stably.

The floating structure of the present invention is industrially useful because it can be used as an observation buoy at sea.

REFERENCE SIGNS LIST 10 Floating body structure 12 Floating body 14 Motion suppression plate 16 Floating body main body 18 Floating body protrusion 20 Gap 22 Bracket 24 Container 26 Anchor 28 Mooring line 30 Anchor 32 Mooring line 34 Floating body structure 36 Motion suppression plate 38 Gap 40 Bracket 42 Floating body structure 44 Floating body protrusion 46 Floating body structure 48 Floating body protrusion

Claims (6)

A floating structure that floats on the water surface,
A float including a float body whose upper surface appears above water and a float convex portion protruding downward from a lower portion of the float body;
A motion suppression plate is provided around the floating protrusion and inward from the outer circumferential surface of the floating body to suppress motion caused by waves;
Equipped with
A floating structure, characterized in that the motion suppression plate is provided continuously around the entire circumference of the floating convex portion . The floating structure according to claim 1, characterized in that the motion suppression plate is a horizontal plate extending in the circumferential direction and spaced outward from the lower side of the floating protrusion. The floating structure according to claim 1, characterized in that the motion suppression plate is a vertical plate extending in the circumferential direction and spaced downward from the outer bottom of the floating body. The floating structure according to claim 2 or 3, characterized in that the motion suppression plate is provided above the bottom surface of the floating convex portion. A floating structure according to any one of claims 1 to 4, characterized in that the floating body and the floating protrusion are each cylindrical. The floating structure according to any one of claims 1 to 5, characterized in that it is an observation buoy.