CN118289180A

CN118289180A - Floating dock launching stability improvement method

Info

Publication number: CN118289180A
Application number: CN202410377773.5A
Authority: CN
Inventors: 李晓姣; 朱锦标; 娄慧龙; 胡楠; 王雅琪; 何儒; 柳梦源
Original assignee: Jiangnan Shipyard Group Co Ltd
Current assignee: Jiangnan Shipyard Group Co Ltd
Filing date: 2024-03-29
Publication date: 2024-07-05

Abstract

The invention discloses a method for improving the stability of floating dock launching, which comprises the step of providing a floating dock, wherein a loading object is loaded on the floating dock. Calculating the stability height KM and the initial stability height GM ₀ of the buoyancy body after the floating dock loaded with the loading object is put into water; judging whether the value of the initial stability height GM ₀ meets the requirement or not based on the minimum value GM _{Minimum of} of the allowable initial stability height of the floating dock; when the judgment result is that the requirement is not met, calculating a difference value delta GM=GM ₀-GM_{Minimum of} <0, and adding the steady-center height KM value of the buoyancy body to GM _{Minimum of}-GM₀. According to the further scheme, the buoyancy tank is added on the deck of the floating dock, so that the KM value is improved, the stability of the floating dock in launching can be effectively improved, and the problem that the floating dock cannot be launched due to instability is solved.

Description

Floating dock launching stability improvement method

Technical Field

The invention relates to the technical field of ship construction, in particular to a method for improving the launching stability of a floating dock.

Background

A floating dock is a marine floating platform for ship repair. The floating dock can float on water and can move, and is an integral structure consisting of dock walls and dock bottoms at two sides. The wall and the bottom are of box-shaped structures and are divided into a plurality of sealed compartments. The other compartments are water compartments, and the dock is sunk or floated by water filling or water draining. The bilge is used to provide buoyancy and support the vessel. The dock wall has the function of providing the integral stability of the dock and working rooms required by dock repairing equipment and production. When a ship to be repaired is docked, water is firstly poured into the water tank, the dock is sunk to the depth of the water in the dock to meet the requirement of the water depth of the ship for docking, the ship is pulled by traction equipment for docking, and then the water in the water tank is drained, so that the dock floats to the bottom of the dock to expose the water surface, and the operation can be performed. After the ship is repaired, the ship is undocked by reverse procedure.

When the floating dock is submerged, due to the fact that the load (such as a giant ring section and a large ship) is relatively heavy or the gravity center is relatively high, the stability of the submerged working condition is insufficient, after the deck surface of the floating dock is submerged, due to the fact that only 4 turrets are left, the waterplane is reduced sharply, the value of the stability center height KM (hereinafter abbreviated as 'KM') of the buoyancy body is reduced sharply, and finally the initial stability height GM (hereinafter abbreviated as 'GM') is negative, so that the floating dock cannot be submerged. Therefore, after the deck surface of the floating dock is launched, the water plane is drastically reduced, and the stability of the floating dock is reduced, so that the problem that the floating dock cannot launch due to instability is urgently solved.

Disclosure of Invention

In view of the above drawbacks of the prior art, an object of the present invention is to provide a method for improving the stability of launching a floating dock, so as to improve the stability of the floating dock during launching, and avoid the problem of failing to launch due to instability.

To achieve the above and other related objects, the present invention provides a method for improving the stability of a floating dock, comprising:

providing a floating dock, wherein the floating dock is loaded with a loading object;

Calculating a stability height KM value and a primary stability height GM ₀ value of a buoyancy body after the deck surface of a carrying object of the floating dock carrying the carrying object is immersed in water;

Judging whether the value of the initial stability height GM ₀ meets the requirement or not based on the minimum value GM _{Minimum of} of the allowable initial stability height of the floating dock;

When GM ₀＜GM_{Minimum of}, the difference Δgm=gm ₀-GM_{Minimum of} <0 is calculated and the buoyancy body steady-center height KM value is increased to GM _{Minimum of}-GM₀.

Optionally, the step of calculating the center height KM value and the initial stability height GM ₀ value of the buoyancy body after the deck surface of the floating dock loaded with the load is immersed in water based on the parameters of the floating dock includes:

And modeling and loading are carried out by adopting NAPA software, and the stability height KM value and the initial stability height GM ₀ value of the buoyancy body after the deck surface of the loading object of the floating dock loaded with the loading object is immersed in water are calculated.

Optionally, in the step of increasing the buoyancy body center height KM value to GM _{Minimum of}-GM₀, the method comprises:

And adding a buoyancy body on a cargo deck of the floating dock to ensure that the steady height KM value of the buoyancy body reaches GM _{Minimum of}-GM₀.

Optionally, the buoyancy body is a buoyancy tank, and the buoyancy body is added on an added cargo deck on the floating dock, so that the step of stabilizing the center height KM value of the buoyancy body to GM _{Minimum of}-GM₀ comprises the following steps:

calculating the relation between a single buoyancy tank and the KM value for increasing the steady height of the buoyancy body according to the size of the buoyancy tank;

And calculating the number of the added buoyancy tanks based on the relation between the single buoyancy tank and the KM value of the stability height of the added buoyancy body.

Optionally, after calculating the number of the increased buoyancy tanks, further comprising:

the buoyancy tank is disposed at a position near the side of the board.

Optionally, the buoyancy tank is formed by enclosing a bottom plate, a side longitudinal wall plate extending along the edge of the bottom plate in a direction vertical to the bottom plate, and a top plate arranged at the extending end of the side longitudinal wall plate.

Optionally, the bottom plate of the buoyancy tank is welded to the deck surface of the floating dock by a backing plate.

Optionally, a manhole cover is arranged on the top plate of the buoyancy tank, and a manhole cover is arranged at the bottom of the side longitudinal wall plate.

Optionally, a hanging bracket is arranged on the top plate of the buoyancy tank.

Optionally, only the turret structure is provided on the main deck of the floating dock.

Compared with the prior art, the floating dock launching stability improving method has at least the following beneficial effects:

The method for improving the launching stability of the floating dock comprises the step of providing a floating dock, wherein the floating dock is loaded with a load. Calculating a stability height KM value and a primary stability height GM ₀ value of a buoyancy body after the deck surface of a carrying object of the floating dock carrying the carrying object is immersed in water; judging whether the initial stability height GM ₀ meets the requirement or not based on the minimum value GM _{Minimum of} of the allowable initial stability height of the floating dock; when the judgment result is that the requirement is not met, calculating a difference value delta GM=GM ₀-GM_{Minimum of} <0, and adding the steady-center height KM value of the buoyancy body to GM _{Minimum of}-GM₀. Through increasing the stable center height KM value of the buoyancy body, the primary stability height GM ₀ value is not more than 1m, and the safe water drainage is further ensured.

Furthermore, a certain number of buoyancy body structures are additionally arranged on the deck of the floating dock to enlarge the water plane, such as a unit buoyancy tank, so that the stability of the floating dock is improved, the stability height KM value of the buoyancy body is improved, and the problem that the floating dock cannot be drained due to instability is avoided. The method of adopting the unit buoyancy tanks is integrated into zero, and the unit buoyancy tanks with different numbers are matched and installed, so that the KM value can be accurately improved.

Drawings

FIG. 1 is a flow chart of steps of a method for improving stability of a floating dock according to an embodiment of the present invention;

FIG. 2 is a schematic view of the bottom structure of the unit buoyancy tank according to the embodiment of the invention;

FIG. 3 is a schematic top view of a unit buoyancy tank according to an embodiment of the present invention;

FIG. 4 is a schematic side view of a unit buoyancy tank according to an embodiment of the present invention;

FIG. 5 is a schematic side view of a unit buoyancy tank according to an embodiment of the present invention;

Fig. 6 is a schematic structural view of a buoyancy tank arranged in a floating dock according to an embodiment of the present invention.

List of reference numerals:

10. floating box

11. Bottom plate

12. Top plate

13. Hanging bracket

14. Manhole cover

15. Outer longitudinal wall plate

16. Inner side longitudinal wall plate

20. Backing plate

30. Floating dock

31. Tower structure

32. Main deck

Detailed Description

Further advantages and effects of the present application will become apparent to those skilled in the art from the disclosure of the present application, which is described by the following specific examples. The application may be practiced or carried out in other embodiments that depart from the specific details, and the details of the present description may be modified or varied from the spirit and scope of the present application. It should be noted that the following embodiments and features in the embodiments may be combined with each other without conflict.

It should be noted that the illustrations provided in the embodiments of the application are merely schematic illustrations of the basic concepts of the application, and only the components related to the application are shown in the illustrations, rather than being drawn according to the number, shape and size of the components in actual implementation, and the form, number and proportion of each component in actual implementation may be arbitrarily changed, and the layout of the components may be more complicated. The structures, proportions, sizes, etc. shown in the drawings are shown only in connection with the present disclosure for understanding and reading by those skilled in the art, and are not intended to limit the scope of the application, which is defined by the claims, so that any structural modifications, proportional changes, or dimensional adjustments should be made without affecting the efficacy or achievement of the present application.

The primary stability height GM is a main index for measuring the primary stability of the ship. M is primary stability, and KM is primary stability height after the ship is transversely inclined; g is the gravity center, KG is the gravity center height of the ship; GM is the initial stability height of the vessel. The larger the GM, the greater the restoring moment, i.e., the greater the ability to resist the tilting moment. The normal gravity center G is below the stable center M, GM=KM-KG >0, when the ship receives the external force, the restoring moment M _R is opposite to the transverse inclination direction, when the external force disappears, the ship can be restored to the original balance state, and the ship has better stability. When gm=km-KG <0, when the ship receives the external force, the restoring moment M _R is the same as the direction of the transverse inclination, so that the ship can continue to incline and cannot return to the original equilibrium state, and the original equilibrium state is unstable, so that the ship is unstable or overturned.

Considering the fact that the gravity centers of the floating docks are different when carrying different ring segments or ship weights, the improvement requirements of different loads on the primary stability height GM value are not consistent. When the floating dock is deep, the heavy working condition stability is insufficient due to the fact that the weight of the loaded objects (such as a huge ring section and a large ship) is relatively heavy or the gravity center is relatively high, after the deck surface of the floating dock is put into water, the water plane is rapidly reduced due to the fact that only 4 turrets are left, the stability height KM value of the buoyancy body is rapidly reduced, the final initial stability height GM value is negative, and the floating dock cannot be put into water.

The embodiment provides a method for improving the launching stability of a floating vessel, which is characterized in that a certain number of unit buoyancy tanks are additionally arranged on a deck of the floating dock, the waterplane area is increased by a method for adding the unit buoyancy tanks so as to improve the stability of the floating dock, the stability height KM value of a buoyancy body is increased, the initial stability height GM value is not less than 1m, and then the safe launching is ensured. The difference value between the GM stability and the minimum value of the allowable GM of the conventional floating dock is calculated by comparison, and different numbers of unit floating boxes are installed in a matching mode, so that the stability of the floating dock is improved.

Specifically, referring to fig. 1, the method for improving the stability of the floating vessel in the present embodiment includes the steps of:

S1: providing a floating dock, wherein the floating dock is loaded with a loading object;

Referring to fig. 6, above the main deck 32 of the floating dock 30 is only a turret structure 31. And the floating dock 30 is loaded with a load, which may be a giant ring section, a large ship, or the like. In this embodiment, NAPA software may be used to model and load the floating dock 30 and the load, and various parameter information of the floating dock 30 and the load exist in the software.

Because there is the surplus space after the main deck 32 bears the ship and launch, the water plane is insufficient because of the rapid reduction of the water plane after entering water, the stable height KM value of the buoyancy body is rapidly reduced, and the buoyancy dock 30 is loaded with the load, and the gravity center height of the load is higher, so that the final initial stability height GM is negative and instability is easily caused, and the ship cannot launch. The subsequent steps are to calculate the initial stability height GM to determine whether or not the floating dock 30 is unstable under the loading conditions of the floating dock 30 and the load, and how to ensure the safe launching of the floating dock 30 under the condition that the floating dock 30 is unstable.

S2: calculating a stability height KM value and a primary stability height GM ₀ value of a buoyancy body after the deck surface of a carrying object of the floating dock carrying the carrying object is immersed in water;

Based on the setting in the step S1, in this embodiment, the parameter data of the floating dock existing in the NAPA software are used to calculate the center height KM value and the initial stability height GM ₀ value of the floating body after the floating dock carrier deck (main deck) loaded with the loaded object is immersed in water, so as to obtain the center height KM value and the initial stability height GM ₀ value of the floating body after the floating dock carrier deck is immersed in water. The NAPA software is ship stability calculation software, which can rapidly calculate the hydrostatic force of the ship, the loading buoyancy and stability, check the launching safety, KM value= (the area of the water plane is corresponding to the horizontal moment of inertia I _T)/displacement, KG is related to the gravity center height of the loaded object.

S3: judging whether the value of the initial stability height GM ₀ meets the requirement or not based on the minimum value GM _{Minimum of} of the allowable initial stability height of the floating dock;

And (2) judging the primary stability height GM ₀ based on the buoyancy body stability height KM value and the primary stability height GM ₀ value obtained in the step (S2) after the deck surface of the buoyancy dock carrier is immersed in water. In this embodiment, it is determined whether the primary stability height GM ₀ value meets the requirements based on the minimum value GM _{Minimum of} of the allowable primary stability height values of the floating dock. At present, the recommended GM value in the normal operation of the floating dock needs to be not less than 1m, and the embodiment uses the recommended GM value in the normal operation of the floating dock as the basis for judgment. If the value of the initial stability height GM ₀ is larger than 1m, the value of GM ₀ meets the requirement of the floating dock, and the value of the buoyancy body stability height KM is not required to be increased. If the value of the initial stability height GM ₀ is less than 1m, the difference Δgm=gm ₀ -1<0 is calculated and the buoyancy body stability height KM is increased to 1-GM ₀.

S4: when GM ₀＜GM_{Minimum of}, the difference Δgm=gm ₀-GM_{Minimum of} <0 is calculated and the buoyancy body steady-center height KM value is increased to GM _{Minimum of}-GM₀.

When the value of the initial stability height GM ₀ is calculated to be smaller than 1m based on the calculation of step S3, the difference Δgm=gm ₀ -1<0 is calculated, and the buoyancy body steady center height KM value is increased to 1-GM ₀. In particular, the area of the water plane can be increased by adding buoyancy bodies on the cargo deck of the floating dock.

In this embodiment, referring to fig. 6, the buoyancy added to the cargo deck of the floating dock 30 is the unit buoyancy tank 10. The method of adopting the unit buoyancy tanks 10 is integrated into zero, and the unit buoyancy tanks 10 with different numbers are installed in a matching way, so that the stability height KM value of the buoyancy body is improved, namely the stability of the floating dock 30 is improved. Specifically, buoyancy tank 10 is added to floating dock 30 to provide a buoyancy body center height KM value of 1-GM ₀. The number of buoyancy tanks 10 may be calculated according to the following method: firstly, calculating the relation between a single buoyancy tank 10 and the KM value for increasing the stability height of the buoyancy body according to the size of the buoyancy tank 10, and calculating the number of the buoyancy tanks 10 to be increased based on the relation between the single buoyancy tank 10 and the KM value for increasing the stability height of the buoyancy body.

After counting the number of the increased buoyancy tanks 10, the buoyancy tanks 10 may be disposed at the position of the floating dock 30 near the side of the ship so as not to affect the ship passing passage. In this embodiment, referring to fig. 2 to 5, the buoyancy tank 10 is formed by enclosing a bottom plate 11, side longitudinal wall plates extending in a direction perpendicular to the bottom plate 11 along the periphery of the bottom plate 11, and a top plate 12 provided at the extending end of the side longitudinal wall plates, and forms a closed space. Referring to fig. 2, the bottom plate 11 of the buoyancy tank 10 is welded to the deck surface of the floating dock 30 by the pad 20. Referring to fig. 3, a hanging bracket 13 is provided on a top plate 12 of the buoyancy tank 10. In this embodiment, 4 hanging yards 13 are provided on the top plate 12 of the buoyancy tank 10 to facilitate hanging the buoyancy tank 10. A manhole cover 14 is provided on the top plate 12 of the buoyancy tank 10, and the manhole cover 14 is provided to facilitate water injection into the buoyancy tank 10. The bottom of the side vertical wall of the buoyancy tank 10, i.e. the side of the side vertical wall close to the bottom plate 11, is also provided with a manhole cover 14, which manhole cover 14 facilitates draining, inspection and maintenance. Referring to fig. 4 and 5, the longitudinal side walls of the buoyancy tank 10 include an outer longitudinal wall 15 and an inner longitudinal wall 16, and the manhole cover 14 is disposed at the bottom of the inner longitudinal wall 16. Alternatively, the pressure bearing of the buoyancy tank 10 structure is required to meet the hydraulic demand of the maximum submergence depth of the floating dock 30.

In other embodiments, the center height KM of the buoyancy body may be increased by other methods or structures of the buoyancy body, and the embodiment is described by taking the structure of the unit buoyancy tank 10 as an example, which is not a limitation of the present invention.

Referring to fig. 2-6, a floating dock 30a1020 is taken as an example:

1) Firstly, modeling and loading are carried out by using NAPA software, and KM value of water entering the deck surface of the object carried by the floating dock 30 and GM ₀ value of loading working condition are output.

2) The allowable GM value of the conventional floating dock 30 is at least 1, and if the GM ₀ meets the requirement or not according to the judgment value, the difference value is calculated if the GM ₀ does not meet the requirement, and if the difference value Δgm=gm ₀ -1<0, the KM value is increased by 1-GM ₀.

3) Calculating the effect of a single buoyancy tank 10 on KM based on buoyancy tank 10 size using NAPA software, for example, increasing the KM value of a single buoyancy tank 10 to a floating dock 30 by about 0.5m, requires adding (1-GM ₀)/0.5 buoyancy tanks 10.

4) After the number of the floating boxes 10 is determined, the floating boxes 10 are reasonably arranged according to the use condition, and the position of the floating boxes 10 should be close to the side without influencing the ship passing channel;

5) Building a required number of buoyancy tanks 10 according to the drawings of the buoyancy tanks 10;

6) After the buoyancy tank 10 is built, the buoyancy tank 10 is hoisted to a designated position of the floating dock 30, the buoyancy tank 10 is welded with the deck surface of the floating dock 30 through the four-side backing plates 20, and the buoyancy tank 10 is fixed to prevent the buoyancy tank 10 from being separated after entering water;

7) Closing the manhole covers 14 on the upper and lower sides of the buoyancy tank 10, ensuring the water tightness of the buoyancy tank 10, and preventing the buoyancy tank 10 from water inflow in the subsequent deep sinking process;

8) For step 7), if the floating loading scheme needs to fill the buoyancy tank 10 with water, closing the lower manhole cover 14, opening the upper manhole cover 14, closing the upper manhole cover 14 after water injection, and checking that water leakage cannot occur;

9) After checking safety, draining according to a loading scheme;

10 After the water draining work is completed, if the buoyancy tank 10 has water, the bottom manhole cover 14 is opened to drain, and the bottom water is manually pumped out through a belt;

11 The buoyancy tank 10 may be lifted off the floating dock 30 or reserved according to a plan to wait for the next sinking and floating operation.

Referring to fig. 2 to 5, the unit buoyancy tank 10 in the present embodiment is designed as follows:

1) The buoyancy tank 10 is set to be long by wide by high in size according to the requirements.

2) The top plate 12 of the buoyancy tank 10 is provided with 4 lifting horses, so that the buoyancy tank is convenient to lift. There is 1 manhole cover 14 to facilitate water injection.

3) The bottom of the buoyancy tank 10 and the periphery of the floating dock 30 are welded and fixed through the backing plate 20.

4) The bottom of the inner vertical wall 16 of the buoyancy tank 10 is provided with 1 manhole cover 14, which is convenient for discharging water.

5) The buoyancy tank 10 is configured to bear pressure to meet the hydraulic demand of the maximum submergence depth of the floating dock 30.

In summary, the method for improving the stability of a floating dock according to the present invention includes providing a floating dock with a load thereon. Calculating the stability height KM and the initial stability height GM ₀ of a buoyancy body after the deck surface of a carrying object of the floating dock carrying the carrying object is immersed in water; judging whether the initial stability height GM ₀ value meets the requirement or not based on the minimum value of the allowable initial stability height GM value of the floating dock; when the judgment result is that the requirement is not met, calculating a difference value delta GM=GM ₀ -1<0, and increasing the steady-center height KM value of the buoyancy body to 1-GM ₀. Through increasing the stable center height KM value of the buoyancy body, the primary stability height GM ₀ value is not more than 1m, and the safe water drainage is further ensured.

The above embodiments are merely illustrative of the principles of the present invention and its effectiveness, and are not intended to limit the invention. Modifications and variations may be made to the above-described embodiments by those skilled in the art without departing from the spirit and scope of the invention. Accordingly, it is intended that all equivalent modifications and variations of the invention be covered by the claims, which are within the ordinary skill of the art, be within the spirit and scope of the present disclosure.

Claims

1. A method of improving stability in a floating dock, comprising:

Providing a floating dock, wherein the floating dock is loaded with a load;

Based on the minimum allowable primary height GM _{Minimum of} of the floating dock, comparing the primary height GM ₀ with the minimum allowable primary height GM _{Minimum of};

2. The method for improving the stability of a floating dock according to claim 1, wherein the step of calculating the center height KM value and the initial stability height GM ₀ value of the buoyancy body after the deck surface of the floating dock loaded with the load is immersed in water based on the parameters of the floating dock comprises:

3. The method of improving the stability of a floating dock according to claim 1, wherein in the step of increasing the center of stability KM value of the buoyancy body to GM _{Minimum of}-GM₀, comprising:

4. A method of improving the launch stability of a floating dock according to claim 3, wherein the buoyancy body is a buoyancy tank, and wherein the step of adding the buoyancy body to the added cargo deck of the floating dock to a center height KM value to GM _{Minimum of}-GM₀ comprises:

5. The method for improving the stability of the floating dock according to claim 4, further comprising, after counting the number of the floating tanks, the steps of:

The buoyancy tank is disposed at a position near the side.

6. The method for improving the stability of a floating dock according to claim 4, wherein the floating tank is formed by enclosing a bottom plate, side longitudinal wall plates extending in a direction perpendicular to the bottom plate along edges of the bottom plate, and top plates provided at extending ends of the side longitudinal wall plates.

7. The method of improving the launch stability of a floating dock of claim 6, wherein the bottom plate of the buoyancy tank is welded to the deck surface of the floating dock by a spacer plate.

8. The method of improving the stability of a floating dock according to claim 6, wherein a manhole cover is provided on a top plate of the floating tank, and a manhole cover is provided on a bottom of the side wall plate.

9. The method of improving the stability of a floating dock according to claim 6, wherein a hanging bracket is provided on a top plate of the floating box.

10. The method of improving the stability of a floating dock according to claim 2, wherein only a turret structure is provided on a main deck of the floating dock.