JPH0353159B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a ship with a stabilizing device.

Various methods have been proposed to stabilize ships. One method is to install roll control tanks on the ship. Two combined tanks are mounted on either side of the ship, and the connection between the tanks has a throttle for energy dissipation. Similarly, pitching control is provided by two connected tanks spaced longitudinally within the ship. Such roll and pitch control devices have limited effectiveness and, moreover, they are unable to provide stability against heave.

Another known method of attempting to stabilize against rolling involves the use of movable wings on the bow of a movable vessel. The presence of these wings creates lift as the ship moves forward, and the attitude of the wings can be changed in response to changes in the ship's attitude for stability purposes. This method is unsatisfactory.
This is because this method relies on the existence of significant forward speed and therefore cannot be operated when the ship is stationary or moving slowly. Moreover, such wings cannot provide stability against heaving.

According to the invention, at least one chamber is arranged such that when at least a part of the ship is submerged in the water it is at least partially submerged, in the chamber between the underlying water and the overlying air. an opening in the chamber that is permanently open and in communication with the water to allow water to flow in and out of the chamber; an opening in the chamber that is open at all times and that allows water to flow in and out of the chamber; A chamber that is selectively movable between a first position in which the chamber is connected to the atmosphere and a second position in which the chamber is not so connected so as to allow air to flow into and out of the chamber. a valve arrangement for controlling the buoyancy of the valve, and said valve arrangement operable to maintain said valve arrangement in either said first position or said second position through a significant number of wave cycles. Provided is a ship having at least a stabilizing device for mitigating up-and-down heaving, characterized in that it is equipped with a control device for controlling.

In this case, it is preferred that there are at least two spaced apart chambers.

In this specification, the term vessel refers to any structure capable of floating in water or sea water in immersed or semi-immersed form, such as in the form of a regular ship, barge, raft, semi-submersible and submersible. shall be given the meaning.

The chamber is arranged within the vessel such that the stabilizing device stabilizes the vessel at least against heaving and optionally also against pitching or rolling.

The present invention will be explained in more detail below using the accompanying drawings.

1 and 2 show a semi-submersible vessel 10. FIG. This ship has a pair of parallel floats 11, four outer support legs 12 attached to each end of the floats 11, and a platform deck 13 fixed to the upper end of the outer support legs 12 for bridging the floats 11. are doing. The platform deck 13 is further supported by inner support legs 14, which are arranged along the float 11. 15 parts
A frame structure, indicated by , is present between at least some of the adjacent pairs of legs 12, 14 to provide lateral stiffness to the vessel.

Each outer support leg 12 has a chamber 1 at its bottom.
6. In figures 1 and 2, chamber 1
6 is shaded. Each chamber 16 is open at its lower end 17 so that the first and second
As shown in the figure, when the vessel 10 is semi-submerged underwater, water freely enters the chamber 16 from the end 17. Solid line A in Figures 1 and 2 indicates the level of still water. Chamber 16 is sized such that chamber 16 is partially filled with water when vessel 10 is balanced in still water, as shown in FIGS. Each chamber includes one valve (not shown) which separates the chamber from a first position in which the chamber is in communication with the atmosphere so that air may enter and exit the chamber; It is selectively operable to a second position.

In the embodiment shown in FIGS. 3 and 4, in addition to arranging the buoyancy chamber 16 in the support leg 12, the buoyancy chamber 116 is arranged on the exterior of the ship, for example as a concentric ring on a vertical cylindrical leg. . Any suitable number of such external buoyancy chambers may be used, with eight chambers being used in the embodiment of FIGS. 3 and 4. As will be readily appreciated, the external chamber can be used in place of, rather than in addition to, internal buoyancy. There are economic benefits to attaching the buoyancy chamber to the exterior of the ship. This is because a stabilizing device according to the invention can be retrofitted onto ships already in operation. Concentric rings are just one possibility for attaching a buoyancy chamber to the exterior of the hull. Numerous other external buoyancy chamber locations can be used. A secondary effect of some external buoyancy chamber attachments is that deck loads can be substantially increased over those of ships without them.

Both outer buoyancy chamber 116 and inner buoyancy chamber 16 are located partially above the still water level and partially below the still water level.

5 and 6 show one structure of chamber 116 in more detail. This chamber is open to the sea at its lower end 117. This chamber is divided into three compartments by a partition wall 140. The partition wall 140 is a horizontal partition wall 1
It extends vertically downward from 41 to the lower end 117.
These compartments are not required, but assist in stabilization control. This is because the annular chamber 116 can be treated as three independent compartments. Valve 129 controls the flow of air through duct 142 that communicates with the top of the compartment. The duct 142 is connected by a valve 129 to a pipe 144 which communicates with the atmosphere. The details shown inside circle M are common to each compartment.

It should be noted here that although in FIGS. 5 and 6 the division of the buoyancy chamber is shown with respect to the external buoyancy chamber, it is equally possible to divide the internal buoyancy chamber. The valve for the chamber (valve 129 in FIGS. 5 and 6) can be fully opened or fully closed in response to an open or close command issued by the controller. When a given valve is open and the water level in the corresponding chamber is forced up by wave motion, the air trapped at the top of the chamber is free to leave the chamber and vent to the atmosphere. The water level within the chamber can therefore rise substantially unimpeded. On the other hand, if the level of water in the chamber is forced down by wave motion, the communication to atmosphere through the valve allows the level of water in the chamber to drop without substantial resistance. however,
If a given valve is closed and then the level of water in the corresponding chamber attempts to rise or fall, such rise or fall will be resisted by the compression or expansion of the air trapped in the upper part of the chamber. It can only be done against force. In this case, therefore, the rise or fall of the water level in the chamber is prevented. In this way, the valve operation controls chamber buoyancy fluctuations and provides corresponding stabilization.

The state of the valve is controlled by the aforementioned controller, which is designed to calculate the peak frequency and spectrum of the ship's heave, roll and pitch that is occurring. A pre-generated "lookup" table is then referenced within the controller's algorithm to read the optimal valve fully open or fully closed configuration for maximum motion relief. This configuration is communicated to the valve as a command for valve operation.
Auxiliary manual equipment and valve configuration monitoring equipment can be installed to provide the controller with a basis for making decisions for the selected valve configuration. The controller can be operated automatically.

The valves connecting the buoyancy chamber to the atmosphere remain open or closed during a storm to change the state of the boat, rather than being operated to open and close within the wave cycles of individual wave crests/troughs.

Figures 7, 8 and 9 are barges or monohulls in which internal buoyancy chambers are located.
It shows the shape of Chamber 16a is attached to the bow, and chamber 16b is attached to the stern. Each chamber is divided into four compartments. These help reduce heaving and pitching caused by heading waves. Two further chambers 16c on either side of the ship cushion the heave and roll caused by transverse waves. Although not shown, bulkheads can also be installed to divide these chambers. In Figures 7, 8 and 9, the normal internal water level is shown at T, which is the same as the external water level A. All chambers are open at their lower ends 17.

As can be readily seen, by installing a buoyancy chamber arranged as shown in Figures 1 and 2, the ship can be stabilized against heaving, pitching and rolling.

When using this stabilizing device on a conventional ship, it is first possible to arrange a pair of open-ended chambers along the length of the ship. In this case, it is possible to prevent vertical shaking and pitching, but it is not possible to prevent horizontal shaking. Alternatively, a pair of chambers can be arranged laterally, but in this case, it is possible to prevent rolling and vertical shaking, but it is not possible to prevent pitching. However, another possibility is to use a single chamber rather than multiple buoyancy chambers, although the range of conditions that can be stabilized is more limited. Easy chamber 1
6, a chamber in which the piston can move up and down can be used. This piston separates the air above it from the water below. Yet another possibility is to use a chamber whose internal shape can be varied to control stabilization. For example, an inflatable toroidal bag may be attached to the inner wall of the chamber, and the bag may be inflated.
Contraction changes the internal cross-sectional area of the chamber in a region along its height, thereby causing the buoyancy of the chamber to change in a predetermined manner in response to changes in the level of water within the chamber. You can change the format.

[Brief explanation of drawings]

The accompanying drawings show an embodiment of the invention, in which FIG. 1 is a schematic end view of a semi-submersible vessel with a stabilizing device, FIG. 2 is a schematic side view of the vessel of FIG. 3 is a schematic end view of a semi-submersible vessel having an alternative type of stabilization device, FIG. 4 is a schematic side view of the semi-submersible vessel of FIG. 3, and FIG. 5 is a schematic side view of the semi-submersible vessel of FIG. and a more detailed view of one of the buoyancy chambers shown in FIG. 4, and FIG.
Figure 7 is a schematic diagram of a barge or monolithic ship equipped with a stabilizing device;
9 is a schematic plan view of the barge or monolithic vessel of FIG. 7, and FIG. 9 is a schematic sectional view of the barge or monolithic vessel of FIGS. 7 and 8. In the figure, 10...semi-submersible vessel, 11...float,
12... Outer support leg, 13... Platform deck, 14... Inner support leg, 15... Frame structure, 16, 16a, 16b, 1
6c...buoyancy chamber, 17...lower end of opening of 16, 1
DESCRIPTION OF SYMBOLS 16... Buoyancy chamber, 117... Opening lower end of 116, 129... Valve, 140... Bulkhead, 141... Horizontal bulkhead, 142... Duct, 144... Pipe.

Claims (1)

[Scope of Claims] 1. At least one chamber arranged to be at least partially underwater when at least a portion of the ship is submerged in the water; an interface defined between the chambers, an opening in the chamber that is permanently open and in communication with the water and allows water to flow in and out of the chamber, a lowering or raising of the level of water in the chamber due to wave action; selectively movable between a first position in which the chamber is in communication with the atmosphere and a second position in which the chamber is not so connected to allow air to flow into and out of or into the chamber accordingly. a valve arrangement for controlling the buoyancy of the chamber, and said valve operable to maintain said valve arrangement in either said first position or said second position through a significant number of wave cycles; A ship having at least a stabilizing device for mitigating up-and-down motion, characterized in that it is equipped with a control device for controlling the device. 2. A ship according to claim 1, wherein the plurality of chambers are spaced apart from each other along the length of the ship to compensate for pitching and heaving. 3. A ship according to claim 1, wherein a plurality of chambers are spaced laterally of the ship to compensate for rolling and heaving. 4. The ship according to claim 1, wherein the or each chamber is provided outside the ship. 5. The ship according to claim 1, wherein the or each chamber is provided inside the ship. 6. The ship according to claim 1, having a plurality of chambers, at least one of which is provided outside the ship, and at least one of which is provided inside the ship. 7. The ship according to claim 1, wherein the interior of the or at least one chamber is partitioned into a plurality of compartments. 8 (a) A ship is provided with at least one chamber arranged so that when at least a part of the ship is submerged, it is at least partially submerged, in which the underlying water and overlying air are connected. (b) the chamber is provided with an opening in the chamber which defines an interface between the chambers and which is open at all times and is in communication with the water and allows water to flow into and out of the chamber; selectively between a first position where the chamber is connected to the atmosphere and a second position where the chamber is not so connected so as to allow air to flow into and out of the chamber as the level decreases or increases; (c) providing a valve arrangement for controlling the buoyancy of a movable chamber; (c) causing the valve arrangement to assume said first or second position in accordance with the periodic repeatability of the waves accompanying the ship; (d) maintaining the valve arrangement in said assumed position through a significant number of wave cycles; and (e) repeating the steps of (c) and (d) above. How to stabilize a ship for mitigation.