CN107580579B

CN107580579B - System for ship control

Info

Publication number: CN107580579B
Application number: CN201680013604.7A
Authority: CN
Inventors: 延斯·伯蒂尔·阿恩·艾尔罗斯
Original assignee: Csl Holdings Ltd
Current assignee: Csl Holdings Ltd
Priority date: 2015-03-04
Filing date: 2016-03-04
Publication date: 2020-04-10
Anticipated expiration: 2036-03-04
Also published as: CN107580579A; KR102554633B1; DK178739B1; WO2016139627A1; KR20170128357A; EP3265374A1; MY194309A; DK201570119A1

Abstract

The invention relates to a system suitable for controlling the buoyancy of a vessel, the vessel being a Catamaran (CAT), the catamaran being suitable for operation in a first CAT mode, the catamaran being suitable for operation in a second SWATH mode, the catamaran comprising a plurality of ballast tanks, the ballast tanks being largely empty in the first CAT mode and largely filled with water in the second SWATH mode. The object of the invention is to improve the stability of the vessel in CAT mode and in swing mode. The object of the invention is achieved if the weight of the empty vessel is distributed towards the centre of the vessel in the first CAT mode and ballast water is distributed towards the ends of the vessel in the second swing mode. Hereby it is achieved that a vessel designed to operate in two different modes of operation, wherein the first CAT mode is preferred for the transport of the vessel, which is very efficient, since the vessel operates at a relatively high level and in the CAT mode the waterline is along both hulls of the vessel.

Description

System for ship control

Technical Field

The invention relates to a system suitable for controlling the buoyancy of a vessel, the vessel being a Catamaran (CAT), the catamaran being adapted to operate in a first Catamaran (CAT) mode, the catamaran being adapted to operate in a second small-waterplane catamaran (SWATH) mode, the catamaran comprising a plurality of ballast tanks, the ballast tanks being largely empty in the first CAT mode and largely filled with water in the second SWATH mode.

Object of the Invention

The object of the invention is to improve the stability of the vessel in both the first CAT mode and the second SWATH mode.

Disclosure of Invention

The object of the invention is achieved by the system disclosed in the opening paragraph and which is further developed in that in the first CAT mode the empty ship mass is distributed towards the centre of the ship and in the second SWATH mode the ballast water is distributed towards the ends of the ship.

Hereby it is achieved that a ship designed to operate in two different modes of operation, wherein the first CAT mode is preferred for the transport of the ship, which is very efficient, since the ship operates at a lower draft and in the first CAT mode the waterline is along both hulls of the ship. In the empty vessel first CAT mode, most of the mass of the vessel is concentrated towards the center of the vessel. In this way, a relatively small moment of inertia can be maintained and the efficiency of the active mode control foil and interceptor is improved, and the system can include one or more foils and/or interceptors that are controlled by the active ride control system.

Hereby is achieved that the longitudinal metacentric height in the first CAT mode is located higher above the vessel. Thus, the stability of the ship is increased and the ship can be run at a relatively high speed with relatively low fuel consumption, since a large part of the ship is above the water surface. Only two hulls must be driven in the water. While in the second SWATH mode the vessel is relatively low in the water and the water plane is now distributed over the legs connecting the upper part of the vessel to the water hull. In this way the vessel is heavier, because the ballast tanks are now filled with seawater, which results in a mass distribution of the vessel that forms a heavy counterweight for both ends of the vessel. In this way, it is achieved that the longitudinal pitch center is located lower than the longitudinal pitch center in the first CAT mode. Hereby is achieved that the vessel now forms a relatively stable working platform, which vessel moves at a lower speed than in the first CAT mode. At the front end of the vessel, mainly in the two longitudinal hulls, the position of the vessel in the water can be changed by changing the angle of inclination of the lamellae, whereby the pitch and roll-over forces acting on the hulls can be increased or decreased by the lamellae. The draft on both sides of the front end of the ship can be changed, so that the quick pitching adjustment and overturning adjustment of the ship body can be realized.

In a preferred embodiment of the invention, in the first CAT mode, the centre of buoyancy of the vessel may be located mid-stern. Whereby a further hydrodynamic stabilisation of the vessel can be achieved. In the first CAT mode, the seawater ballast tank will normally be empty, but the water level in the ballast tank may be adjusted.

In another preferred embodiment of the present invention, the fast-acting seawater ballast system may be driven by at least one air compressor in the first CAT mode of operation. By means of the ballast system, the amount of ballast that can be influenced by the compressor can be changed relatively quickly, in one case the compressor can fill the ballast tank by lowering the pressure above the water level in the tank, and in the opposite case the same compressor can increase the gas pressure above the water level, thereby pressing the water out of the ballast tank. The compressor may be operated in conjunction with multiple compartments, but in a preferred embodiment, there is one compressor per compartment. When working with one compressor per compartment, the compressors may be connected in a tubular manner, so that in case of failure of one of the compressors, the compressor can take over the function of the other compressor.

In another preferred embodiment of the invention, in the second SWATH mode, the waterplane area may be distributed over three or more legs. A very limited water plane is thereby achieved in the second SWATH mode, since the water plane only surrounds the legs connecting the upper part of the vessel and the relatively small area of the two longitudinal hulls. In this way the effect of the waves rolling along the vessel is very limited, since the drift volume down to or above the water level is very limited.

In another preferred embodiment of the invention, in the second swing mode, a major portion of the waterplane area may be concentrated toward the center of the ship. Hereby it is achieved that the longitudinal metacentric is located relatively low.

In another preferred embodiment of the invention, in the second SWATH mode, the fast acting seawater ballast system may be driven by an air compressor for the flatbed of the vessel. By means of the air compressor, the pressure in the seawater ballast tank can be changed, the ballast tank can be filled with seawater by reducing the air pressure above the water level, and the ballast tank can be emptied by increasing the air pressure above the water level.

In another preferred embodiment of the present invention, the vertical acceleration of the vessel can be reduced by increasing the moment of inertia of the vessel by increasing the weight of the vessel and by maximizing the distance between the ballast water and the center of gravity of the vessel.

The large vertical acceleration of the vessel has a number of negative effects on the maneuverability of the vessel and its crew. The vertical acceleration is directly related to the metacentric height, which is a measure of the initial static stability of the float.

In this case the float is a catamaran, which can be taken up by a fast-acting seawater ballast system into the second SWATH mode (small waterplane catamaran). A large metacentric height generally results in a large acceleration. Too small a trim centre height impairs the stability of the ship.

The height of the fixed inclination center is calculated according to the distance between the gravity center (G) of the ship and the fixed inclination center (M) of the ship. The trim center is determined by the ratio between the inertial resistance of the vessel and the volume of the vessel. The inertial resistance quantifies how the water surface area at the waterline is distributed to resist overturning. For ships, it is common to speak of a longitudinal trim center height (M)_L) And transverse metacentric height (M)_T) Which refers to the initial static stability of the vessel in terms of pitch and roll, respectively. In order to realize a large longitudinal trim height, it is preferable to distribute a large water surface area which is concentrated toward the end of the hull.

Furthermore, acceleration may be reduced by increasing the moment of inertia of the vessel. In practice this can be achieved by increasing the mass of the vessel and maximizing the distance between the counterweight and the centre of gravity of the vessel. Light weight vessels generally have greater acceleration than heavier vessels.

However, hull design features that contribute to high speeds result in the waterline area being concentrated toward the aft end of the vessel and thereby increasing the trim center height. Light weight is also preferred to achieve high cruising speeds with low fuel consumption. Furthermore, this results in a large acceleration of the ship.

The reason for changing to the second SWATH mode is to eliminate the poor acceleration performance of the high speed catamaran hull by utilizing the principles described above. The waterplane area is minimized and concentrated toward the center of the ship. Because the ballast tanks are filled with seawater, the mass increases and the position of the tanks further increases the moment of inertia. The result is a vessel that has the characteristics of a high speed catamaran and the advantages of a very stable working platform for a SWATH vessel. All of this is made possible by a fast-acting seawater ballast system driven by an air compressor.

First CAT mode

The floating center is positioned at the position near the stern of the center of the ship

The weight of the unloaded ship is distributed to the center of the ship

Quick-acting seawater ballast system driven by air compressor

Operating an active ride control system via a plurality of lamellae and/or interceptors

Second SWATH mode

The surface area of the water line is distributed on three or more legs

The major part of the water surface area is concentrated toward the center of the ship

Distribution of ballast water to the end of a vessel

Quick-acting seawater ballast system driven by air compressor

Drawings

Figure 1 illustrates a cross-sectional view of a ship.

Figure 2 illustrates another cross-sectional view of the present invention.

Detailed Description

Fig. 1 illustrates a cross-sectional view of a vessel 4, wherein the vessel comprises a deck or upper portion and underwater hulls 6, 8, wherein the underwater hulls 6, 8 comprise

front ballast tanks

10, 12 and

rear ballast tanks

14, 16. Further, there are indicated

nacelles

18, 20 and, on deck, indicated forward compressors 22, 24 and aft compressors 26, 28.

In the first CAT mode, the

ballast tanks

10, 12 and 14, 16 are mostly empty when the vessel 2 is operating. The relatively heavy mass of the vessel is concentrated in the

nacelles

18, 20. So most of the weight of the vessel is concentrated near the center. In the first CAT mode, where the mass is concentrated in the midship, a relatively high longitudinal trim center position is achieved. In the reverse situation, when the

ballast tanks

10, 12 and 14, 16 are mostly filled with water, the vessel operates in the second SWATH mode. The weight of the ballast water is now located at the front and rear of the hull. This will result in a position of mostly lower longitudinal metacentric height. Whereby relatively stable operating conditions are achieved when the vessel has to be operated, for example, close to a open sea wind power plant. This second SWATH mode is very effective for keeping the vessel very stable, but not for long range voyages.

Fig. 2 illustrates another cross-sectional view of the invention, but now a cross-sectional view at a level below the water level. Fig. 2 indicates two underwater hulls 6, 8, which include

ballast tanks

10, 12, 14 and 16. Furthermore, designated

nacelles

18 and 20 are placed in the hulls 6, 8. In the

cavities

30 and 32 of the hulls 6, 8 there are indicated forward thrusters. The front thruster necessarily comprises one or more propellers that can operate in the

channels

30, 32. Furthermore, there are indicated

lamellae

34, 36 which are operated by

actuators

38, 40. Additional foils and/or interceptors may be provided near the stern of the ship. At the rear of the hulls 6, 8 there are indicated screw shafts 42, 44 and screws 46, 48. The screws may also be located under the hull.

In operation, the

ballast tanks

10, 12, 14, 16 may be more or less filled with seawater by compressors as indicated in FIG. 1. The

laminae

34, 36 may be tilt or pitch controlled by

actuators

38, 40. This is a very efficient way of achieving further stabilization of the vessel 4, since the foil can be changed quite quickly. If the vessel has some speed before, the pitch and roll angles can be changed by turning the

foils

34, 36, in this way stabilizing the vessel.

Reference numerals used in the drawings

2 System

4 ship

6 ship body

8 boat hull

10 ballast tank

12 ballast tank

14 ballast tank

16 ballast tank

18 nacelle

20 nacelle

22 compressor

24 compressor

26 compressor

28 compressor

30 propeller chamber

32 propeller cavity

34 sheet

36 sheet

38 slice controller

40 sheet controller

42 shaft

44 shaft

46 screw

48 screw

Claims

1. System (2) adapted for controlling the buoyancy of a vessel (4), the vessel (4) being a catamaran, the catamaran being adapted for operation in a first CAT mode, the catamaran being adapted for operation in a second SWATH mode, the catamaran comprising a plurality of ballast tanks (10, 12, 14, 16), in the first CAT mode the ballast tanks (10, 12, 14, 16) being mostly empty, and in the second SWATH mode the ballast tanks (10, 12, 14, 16) being mostly filled with water, characterized in that in the first CAT mode an empty ship mass is distributed towards the centre of the ship, the system comprising one or more lamellae and/or interceptors (34, 36), the lamellae and/or interceptors (34, 36) being controlled by an active travel control system, and in the second SWATH mode ballast water is distributed towards the ends of the vessel, by adding mass to the vessel, and maximizing the distance between the ballast tank (10, 12, 14, 16) water and the center of gravity of the vessel, increasing the moment of inertia of the vessel, thereby reducing the vertical acceleration of the vessel.

2. The system of claim 1, wherein in the first CAT mode, a center of buoyancy of the vessel is located mid-stern.

3. The system of claim 2, wherein in the first CAT mode of operation, the fast-acting seawater ballast system is driven by at least one air compressor (22, 24, 26, 28).

4. The system of claim 3, wherein in the second SWATH mode, a waterplane area is distributed over three or more legs.

5. The system of claim 4, wherein in the second SWATH mode, a major portion of the waterplane area is concentrated toward the midship.

6. The system of claim 5, wherein in the second SWATH mode, the fast acting seawater ballast system is driven by an air compressor (22, 24, 26, 28) for the watercraft's flatbeds.