JPS59199392A - One-point-moored marine structure - Google Patents

Abstract

PURPOSE:To reduce the resistance of external forces such as the wind and waves and a current and to lessen a force required for mooring, by providing an omnidirectional thrustor in each of a plurality of buoyant bodies which are long sideways and rotate horizontally, by mounting thereon a marine structure, such as at an airport, through the intermediary of columns, and by mooring the structure at one point of the seabed. CONSTITUTION:A marine structure A is formed of a deck 1 and a plurality of columns 2 and buoyant bodies 3. The buoyant bodies 3 are formed as pontoons being long sideways. Each of the buoyant bodies 3 is fitted rotatably in the horizontal direction around the central axis Z of the column 2 and provided with an omnidirectional thrustor 4. When an external force F1 caused by a current acts on the structure A under the condition that another external force due to the wind and waves acts thereon, the buoyant bodies 3 rotate in the horizontal direction to be positioned in the state in which a mooring force F4 having the least resistance is obtained. When the omnidirectional thrustors 4 are operated to give a thrust F5, the mooring force F4 can be lessened further to F4', and thus the oscillation of the structure can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a single-point moored offshore structure, and more particularly to a single-point moored offshore structure that reduces the mooring force of relatively large offshore structures such as marine airports. .

Marine buoyant structures are generally constructed as box-shaped so-called pontoons, but external forces such as wind waves and tidal currents act on these structures when they are moored, so they are often similar.

For this reason, it is conceivable to connect a deck located on the sea and a plurality of submerged buoyant bodies by columns, respectively, and to moor the deck at one point so that it can be retraced.

By the way, the external forces that act on such offshore structures can be broadly classified into wind waves and tidal currents, but these generally do not act in the same direction. Therefore, the mooring force in this case is the third
As shown in figure (a), the force F1 due to wind and waves and the force F due to tidal current
2 becomes the reaction force F4 of the resultant force F3.

As a result of intensive studies to reduce this mooring force, the present inventor focused on the fact that wind and waves act on the entire structure, whereas tidal currents act on the submerged parts, mainly the buoyant body, and developed the present invention. I came to do this.

That is, it consists of a deck located on the sea and a horizontally long buoyant body provided at the lower end of a plurality of columns, and at least the buoyant body is configured to be rotatable in the horizontal direction,
It is an object of the present invention to provide a one-point moored offshore structure in which an omnidirectional thruster is attached to the buoyant body and the deck is moored at one point to a base laid on the seabed.

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a single-point mooring offshore working structure according to the present invention will be described below with reference to the drawings.

In Figures 1 and 2, offshore structure A includes a deck 1, a plurality of columns 2 connected to the deck 1, and a plurality of columns 2 connected to the deck 1.
The buoyant body 3 is provided at the lower end of the buoyant body 3.

The buoyant body 3 is formed into a horizontally long so-called pontoon, and is mounted so as to be rotatable in the horizontal direction about the central axis Z of the column 2 as a rotation axis. This buoyant body 3 is provided with an omnidirectional thruster 4.

B is a mooring device that includes a yoke 6 attached to one end of the deck 1 by a hinge 5, a swivel 8 that attaches the other end of the yoke 6 to a mooring buoy 7, and an anchor that connects a base 9 laid on the seabed and the mooring buoy 7. - leg 10. 11 is a flexible joint.

In such a configuration, when an external force F1 due to a tidal current acts on the offshore structure A in a state where an external force due to wind and waves is applied, the buoyancy body 3 rotates in the horizontal direction as shown by the solid line in FIG. 2. That is, it will be located in the state of least resistance. The mooring force F4 at this time is shown in FIG. 3(b), and the mooring force can be reduced. In this state, if the omnidirectional thruster 4 is operated to apply a thruster force F5, the mooring force F4 can be further reduced as shown as F4' in FIG. 3(c).

Particularly in a case such as an airport where the direction of the wind and the direction of takeoff and landing of airplanes are the same, the mooring force can be reduced and the structure can be turned with a small thrust force, which is very effective.

Of course, the present invention is not limited to the embodiments described above, and it is obvious that various changes can be made without departing from the spirit thereof.

[Brief explanation of the drawing]

FIG. 1 is a side view of a one-point moored offshore structure according to the present invention, FIG. 2 is a plan view thereof, and FIGS. 3(a) to 3(c) are explanatory diagrams of mooring force. 1...Deck, 2...Karanoi 3...Floating body, 4...Omnidirectional thruster, 5...Hinge, 6...Yoke, 7...Mooring buoy, 8...Swivel, 9...Base, 10 ... Anchor leg, 11.. Flexible joint, A.. Offshore structure, B.. Mooring device. Agent: Patent Attorney Shin Ogawa − Patent Attorney Ken Noguchi Teru Patent Attorney Kazuhiko Saishita − Jin

Claims (1)

[Claims] It consists of a deck located on the sea, a plurality of columns, and a horizontally long buoyant body provided at the lower end of each column, and at least the buoyant body is configured to be rotatable in the horizontal direction, and the buoyant body is configured to be rotatable in the horizontal direction. A one-point moored offshore structure, characterized in that an omnidirectional thruster is attached and the deck is moored at one point to a base laid on the seabed.