JPH08119190A - Floating structural body provided with moon pool of resistance reduction type - Google Patents

Abstract

PURPOSE: To reduce resistance by generation of eddy currents in a lower end aperture part of a moon pool in navigation for a floating structural body having a moon pool formed of cylindrical surrounding walls penetrating from an aperture edge of an upper deck to an aperture edge of an outer plate of a bottom part. CONSTITUTION: In an aperture part 2b at a lower end of a moon pool 2 formed of cylindrical surrounding walls 2a penetrating from an aperture deck 1a of an upper deck to an aperture edge 1b of an outer plate of a bottom plate, a cover-shaped structural body 4 pivotally attached through a hinge 10 to be opened/closed is composed of a number of vertical plates 4a to part the inside of the aperture part 2b combined like a grid in such a way that generation of eddy currents can be prevented while allowing going in/out of water at the aperture part 2b in the closed condition of the structural body 4 in navigation. Weight of the cover-shaped structural body 4 is thus decreased, while increase of resistance can be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a floating structure such as a floating workbench or a work boat, and more particularly, it has a moon pool formed by a cylindrical wall penetrating from an opening edge of an upper deck to an opening edge of a bottom outer plate. Floating structure.

[0002]

2. Description of the Related Art As a conventional floating body structure having a moon pool, there is a floating body structure as shown in FIG. 7, which is a cylindrical enclosure wall extending from an upper deck opening edge 1a of a hull 1 to a bottom outer plate opening edge 1b. Inside the moon pool 2 formed by 2a, the water surface 3a at the same level as the outer water surface 3 in the stopped state.
Are formed.

[0003]

By the way, in the conventional work boat as described above, when the ship is towed or self-propelled,
A part of the flow 6 along the opening surface of the opening 2b at the lower end of the moon pool 2 flows into the inside of the opening 2b to generate a swirl 5, which causes an increase in resistance.

Therefore, there is also developed a cover provided with a closing lid for completely closing the opening 2b at the time of navigation, but if the opening 2b is closed with such a closing lid, the moon will be shaken as the hull 1 sways. When the water surface 3a in the pool rises or falls below the water surface 3 outside, a large load is applied to the closing lid, so the closing lid must be made extremely robust, which increases weight and costs. Will be increased.

The present invention is intended to solve the above-mentioned problems, and prevents eddy currents from occurring in the opening of the moon pool while allowing water to flow in and out of the opening at the bottom of the moon pool during navigation. It is an object of the present invention to provide a floating body structure with a drag-reducing moonpool that can be suppressed.

[0006]

In order to achieve the above-mentioned object, a floating structure with a drag-reducing moonpool according to the present invention is formed by a cylindrical surrounding wall extending from an opening edge of an upper deck to an opening edge of a bottom skin. And a lid-like structure that is pivotally attached to the opening at the lower end of the moon-pool by a hinge so as to be openable and closable, and means for opening and closing the lid-like structure. In order to prevent eddy currents from occurring in the opening while allowing water to flow in and out of the opening when the structure is closed, the lid-like structure combines a number of vertical plates that partition the inside of the opening. It is characterized by being configured in a grid pattern.

Further, the resistance-reducing type floating structure with a moon pool according to the present invention is characterized in that the lid-shaped structure is formed by arranging a large number of lateral fins in a forward tilted posture.

Further, in the floating structure with a drag pool of the present invention, the opening is formed in a circular shape, and the lid-like structure is provided with a ring member which is aligned with the inner peripheral surface of the opening. It is characterized by being done.

[0009]

In the floating body structure with a moon pool of the present invention described above, the lid-like structure pivotally attached to the opening at the lower end of the moon pool is formed by combining a large number of vertical plates partitioning the opening. Due to the above-mentioned structure, when navigating, water is allowed to flow in and out between the vertical plates in the opening while the lid-like structure is closed, and the vortex flow is generated in the opening. A suppressing action is performed by the plate.

Further, when the lid-like structure is constructed by arranging a large number of forwardly-inclined fins in a row, while allowing water to enter and leave between the fins in the opening during navigation, Due to the forwardly inclined posture of the fins, the action of sufficiently preventing the generation of the vortex in the opening is performed.

Further, the opening is formed in a circular shape,
When the lid-shaped structure has a ring member that matches the inner peripheral surface of the opening, the lid-shaped structure can be firmly configured by attaching the vertical plate or the fin to the ring member. Like

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIGS. 1 to 3 show a floating structure with a moon pool as a first embodiment of the present invention.
Is a longitudinal sectional view thereof, FIG. 2 is a bottom view of the lid-like structure, and FIG.
FIG. 4 is a longitudinal sectional view of an essential part showing an operating state at the time of navigation.

As shown in FIG. 1, also in the case of the present embodiment, the moon pool 2 is formed by the cylindrical surrounding wall 2a penetrating from the upper deck opening edge 1a of the hull 1 as a floating structure to the bottom outer plate opening edge 1b. The water surface 3a is formed inside the moon pool 2 at the same level as the outer water surface 3 in the stopped state.

Further, as shown in FIGS. 1 and 2, a lid-like structure 4 pivotally attached to a circular opening 2b at the lower end of the moon pool 2 via a hinge 10 so as to be openable and closable is provided. As the opening / closing means for the structure, the hinge 10 is configured as a torque hinge in this embodiment. As this opening / closing means, other means combining a winch or a tow line may be used.

The lid-shaped structure 4 has the opening 2 in its closed state.
In order to allow generation of eddy currents in the opening 2b while allowing water to flow in and out of b, a large number of vertical plates 4a partitioning the inside of the opening 2b are combined so as to be orthogonal to each other in a lattice shape. Composed. Then, each vertical plate 4a is joined to a ring member 4b aligned with the inner peripheral surface of the circular opening 2b, and thus the lid-shaped structure 4 is firmly constructed.

Since the floating body structure with a reduced resistance moonpool as the first embodiment is constructed as described above,
At the time of towing or self-propelled navigation, as shown in FIG.
When the lid 2 is closed, the lid-like structure 4 allows water to flow in and out between the vertical plates 4a in the opening 2b, and the opening 2
The vertical plate 4a suppresses the flow 6 along the opening surface of b from flowing into the opening 2b and the generation of the vortex 5, which has the effect of limiting the increase in resistance during navigation to a small extent. can get.

Further, even if the hull 1 sways during navigation, water can freely pass through the lattice-shaped lid-shaped structure 4, so that the load applied to the lid-shaped structure 4 is significantly reduced. ,
As a result, the lid-shaped structure 4 has a light structure, the weight thereof is sufficiently reduced, and the cost can be reduced. Furthermore, if the lid-shaped structure 4 is strongly constituted by the ring member 4b and the ring-shaped member 4b is made hollow so as to have buoyancy, the specific gravity of the lid-shaped structure 4 can be made approximately equal to that of seawater. There is also an advantage that it can be easily opened and closed.

FIG. 4 shows a modified example of the above-mentioned first embodiment, in which the surrounding wall 2a of the moon pool 2 is expanded in a trumpet shape at the lower end portion thereof, and the inside of the moon pool 2 from the work equipment 7 on board. The work hose 9 is hung down through the hose guide pipe 8 extending to the lid-shaped structure 4
As for the first embodiment, a number of vertical plates 4a are provided as in the first embodiment.
The vertical plates 4a are supported by the ring member 4b.

Next, a floating structure with a resistance-reducing moonpool as a second embodiment of the present invention will be described. FIG. 5 is a longitudinal sectional view showing the main part thereof, and FIG. 6 is a bottom view of the lid-like structure. Is. In the case of the second embodiment as well, from the upper deck opening edge 1a of the hull 1 as a floating structure to the bottom outer plate opening edge 1
Moon pool 2 with a cylindrical wall 2a that penetrates up to b
The water surface 3a is formed inside the moon pool 2 at the same level as the outer water surface 3 in a stopped state.

Further, as shown in FIGS. 5 and 6, a lid-shaped structure 4 pivotally attached to the circular opening 2b at the lower end of the moon pool 2 via a hinge 10 so as to be openable and closable is provided. As the body opening / closing means, the hinge 10 is configured as a torque hinge in this embodiment. The lid-shaped structure 4 is provided with a large number of forward fins 4c in the lateral direction so that swirl flow can be suppressed in the opening 2b while allowing water to flow in and out of the opening 2b in the closed state. The fins 4c are arranged in a row, and these fins 4c are connected to a connecting vertical plate 4d in the front-rear direction and also to a ring member 4b aligned with the inner peripheral surface of the circular opening 2b. .

As described above, when the lid-like structure 4 is provided with a large number of forwardly-inclined fins 4c, the fins 4c in the opening 2b are spaced from each other in the closed state of the lid-like structure 4 during navigation. While allowing water to flow in and out, the flow 6 along the opening surface of the opening 2b is suppressed from flowing into the opening 2b by the forwardly tilted posture of the fin 4c, and the vortex flow 5 is generated in the opening 2b. Can be sufficiently prevented. Therefore, also in the case of this embodiment, the same effect as in the case of the above-mentioned first embodiment can be obtained.

[0022]

As described in detail above, according to the floating structure with a moon pool having a reduced resistance of the present invention, the following effects can be obtained. (1) The lid-like structure pivotally attached to the opening at the lower end of the moon pool is constructed in a grid pattern by combining a number of vertical plates that partition the opening so that the lid-like structure can be In the closed state, water is allowed to flow in and out between the vertical plates in the opening, while suppressing the generation of a vortex in the opening. As a result, it is possible to suppress the increase in resistance while making the lid-shaped structure a light structure to simplify the manufacturing and reduce the cost. (2) When the lid-shaped structure is configured by arranging a large number of forwardly-inclined fins, while allowing water to enter and leave between the fins in the opening during navigation, The forward tilted posture has the effect of sufficiently preventing the generation of a vortex in the opening. This allows the above
Although it causes a slight cost increase compared to the case of (1),
The increase in resistance can be significantly suppressed. (3) When the opening is formed in a circular shape and the lid-shaped structure has a ring member aligned with the inner peripheral surface of the opening, the vertical plate or fin is attached to the ring member. The lid-like structure can be firmly constructed.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing a floating body structure with a resistance-reducing moonpool as a first embodiment of the present invention.

FIG. 2 is a bottom view of a lid-shaped structure in the moon pool of the floating structure of FIG.

FIG. 3 is a longitudinal sectional view of an essential part showing a working state of the floating structure of FIG. 1 during navigation.

FIG. 4 is a longitudinal cross-sectional view of essential parts showing a modified example of the floating body structure with a moon pool of FIG.

FIG. 5 is a longitudinal sectional view of an essential part showing a floating body structure with a resistance decreasing type moon pool as a second embodiment of the present invention.

6 is a bottom view of a lid-like structure in the moon pool of the floating structure of FIG.

FIG. 7 is a main part sub-sectional view showing an operating state of a conventional floating structure with a moon pool during navigation.

[Explanation of symbols] 1 Hull as a floating structure 1a Upper deck opening edge 1b Bottom outer plate opening edge 2 Moonpool 2a Enclosure 2b Opening 3 Water surface 3a Moonpool water surface 4 Lid-like structure 4a Vertical plate 4b Ring member 4c fins 4d connection vertical plate 5 vortex flow 6 flow 7 working equipment 8 hose guide pipe 9 working hose 10 torque hinge

Claims (3)

[Claims] 1. A lid provided with a moon pool formed by a cylindrical wall penetrating from an opening edge of an upper deck to an opening edge of a bottom outer plate, and a lid pivotably attached to an opening at a lower end of the moon pool via a hinge. -Like structure and opening / closing means for the lid-like structure are provided, and a vortex is generated in the opening while allowing the water to flow in and out of the opening when the lid-like structure is closed during navigation. In order to prevent the above, the lid-like structure is configured in a lattice shape by combining a number of vertical plates that partition the inside of the opening, and a floating structure with a moon pool having a reduced resistance is characterized. 2. A lid provided with a moon pool formed by a tubular surrounding wall penetrating from an opening edge of an upper deck to an opening edge of a bottom outer plate, and a lid pivotably attached to an opening at a lower end of the moon pool via a hinge. -Like structure and opening / closing means for the lid-like structure are provided, and a vortex is generated in the opening while allowing the water to flow in and out of the opening when the lid-like structure is closed during navigation. In order to prevent the above, the lid-shaped structure is configured by arranging a large number of lateral fins in a forward tilted posture in an array, and a resistance-reducing floating structure with a moon pool. 3. The floating body structure with a reduced moonpool according to claim 1, wherein the opening is formed in a circular shape, and the lid-like structure is aligned with an inner peripheral surface of the opening. A floating body structure with a moon pool having a reduced resistance, characterized by being configured with a ring member.