MXPA06003934A - Apparatus and method for reducing motion of a floating vessel - Google Patents

Abstract

A vessel (2) comprises a first stabilizer assembly (14) and a second stabilizer assembly, each stabilizer assembly comprising at least one submergible at least partially hollow body;and suspending means (16) for suspending the or each body from the vessel, the first and second stabilizer assemblies being suspended from substantially opposite sides of the vessel. Fins (22) are provided on the stabilizer assembly.

Description

APPARATUS AND METHOD TO REDUCE THE MOVEMENT OF FLOTATION OF A BOAT FIELD OF THE I NVENTION The present invention relates to an apparatus and method for reducing the flotation movement of a ship. In particular, but not exclusively, the invention relates to an apparatus and method for reducing movement in the flotation of large ships. BACKGROUND OF THE INVENTION It is well known that ships, barges and other platforms float oscillatingly, the passage and waves in the sea and the undesirable that this movement is in many fields. For example, such movement can be particularly undesirable when loading and unloading to and from ships. This is particularly the case for ships involved with offshore oil and gas industries. In this application, loading and unloading, from and to stationary structures, is common, for example, a platform supported on supports anchored directly to the seabed or from or to another ship. Additionally, in the field of offshore oil or gas, the ships can be extremely large so that, while the movement of the ships is not very large when expressed in degrees of inclination, the movement of heavy platforms is considerable, causing difficulties even in conditions of relative calm. There are many known systems for which the objective is to reduce the rocking and / or pitching movements of floating vessels. There are some systems that have been designed for relatively small vessels. For example, GB 2219973 describes a vessel where there is a passageway in its hull which allows the free flow of water through it. As the passageway is filled and drained, the natural period of pitch / roll movement is increased and the movement response on the ship is reduced. In the improvement of this arrangement, in such a way that a tank is connected to a pump in such a way that the filling and draining of the tank can be controlled at least partially. However, such systems are integral with the same vessel and are expensive, difficult to install and it is not possible to transfer easily from one vessel to another. Another system whose objective is to reduce the instability of a large vessel is described in patent document US 5787832. In that system, the stabilizer assemblies are fixed to the hull of the vessel. Each assembly includes an extension arm and a flotation arm which is fixed at the end. The floats are in contact with the surface of the water at all times and the system works by increasing the effective width of the vessel as well as the netural increase of the period of movement of pitch and roll. Each stabilizing assembly must be fixed to the boat through a very resistant bra capable of supporting very heavy loads. Patent document US 3407766 describes another system whose objective is to reduce the instability of a large vessel by providing a stabilization body below the vessel and stiffened by rigid struts such as steel beams type I that are capable of transmitting a moment of force towards the boat. A great tension towards an arrangement of this kind is the considerable force required by the struts in order to transmit the moment of force from the stabilizing body towards the vessel. SUMMARY OF THE INVENTION It is an object of the invention to provide an apparatus and a method which avoids or mitigates the problem of stabilization systems known and described above. According to a first aspect of the invention, there is provided a vessel comprising a first stabilizing assembly and a second stabilizing assembly, each stabilizing assembly comprising: at least one at least partly hollow submersible body; Y . suspension means for suspending the or each body of the vessel, the first and second stabilizing assemblies are suspended from substantially opposite sides of the vessel. These stabilizer assemblies can be installed in the port or at sea and can be adapted for use with any suitable boat. Because they are at least partially hollow, they can be large for a given mass and the suspension of the boat assemblies can be achieved relatively easily. Each stabilizing assembly is positioned to apply by means of the suspension means, a force directed downwards to one side of the vessel from which it is suspended when that side of the vessel moves upwards. Typically a skimmer assembly is suspended from the port side of the vessel and a stabilizer assembly is suspended from the starboard side of the vessel. This reduces the rocking of the boat, the invention however can be applied to any type of boat some of which are not clearly defined port and starboard (or sides of bow and stern). It should be understood, however, that what we refer to here as the sides of the vessel are those of the boat that go up and down when the boat is subjected to the back and forth movement. The term does not necessarily refer to the port and starboard of the vessel. Frequently the first stabilizing assembly will have a first submersible body but may have: a first partially hollow submersible body and a second partially hollow submersible body; first suspension means for suspending the first body of the vessel; and second suspension means for suspending the second body from the first body. Similarly, the second spraying assembly would often have a single submersible body, but may comprise: a first partially hollow submersible body and a partially submerged partially hollow body; first suspension means for suspending the first body of the vessel; and second suspension means for suspending the second body from the first body. The boat can have a third assembly that is capable of stabilizing, the braking assembly exhibiting: at least one submersible body, at least partially hollow; and means of suspension to suspend the or each body of the vessel. In one embodiment, the first stabilizer assembly is suspended near the bow of a vessel, the third stabilizer assembly is suspended near the stern of the vessel on each side and the second stabilizer assembly is suspended from the other side of the vessel. . The earlier modes that use stabilizing assemblies are known as assymetric arrangements. As well as the first and second sizing assemblies, the third sizing assembly may comprise: a first partially hollow submersible body and a second partially hollow submersible body; first suspension means for suspending the first body of the vessel; and second suspension means for suspending the second body from the first body.

The boat may have a quarry assembly, the curio assembler stabilizer presented: at least one submersible body at least partially hollow; and means of suspension to suspend the or each body of the vessel. The stabilizer assembly can be suspended from the port or the ship's spheribor. In one embodiment the first stabilizer assembly is suspended near the bow of the vessel on one side, the second stabilizer assembly is suspended near the bow of the vessel on the other side, the stabilizer assembly is suspended near the stern of the vessel. The first side of the vessel and the quarry assembly is suspended near the stern of the vessel on the other side. In another mode, the first stabilizer assembly is suspended near the vessel's propagation on one side, the second stabilizer assembly is suspended near the stern of the vessel on the same side, and the third and fourth stabilizer assembly is suspended. suspended to the miíad on the other side of the boat. It will be understood that the assemblies can be placed in any variety of configurations. If the submersible bodies of the assemblies are of the same size, then it may be useful to provide the same number of bodies on each side of the vessel. The reduction of the movement of a boat is based on the fact that the suspension means are capable of applying downwardly directed loads that resist upward movement and the suspension means are fanatically capable of withstanding high voltage loads. Although the suspension means are also capable of withstanding high compression forces, this is not necessary and it is more economical and simple not to procure it. Thus the suspension means are able to withstand loads of tension of more than one hundred times the loads that is capable of being absorbed in compression. The suspension means may consist of elongate flexible members, for example chains, ropes or cables. The or each preferred body is attached to the suspension means in a plurality of places; for example, an elongated body may be attached to an elongate flexible member in the region of each of the opposing ends of the body. Each body preferably is long and also preferentially elongated. Thus in the case where each body is elongated, it may have a cross-sectional area greater than 4 m2 and is preferably greater than 10 m2. Each leather can have one or more closed or closed spaces that have a combined volume greater than 50 m3 and preferably more than 300 m3. The closed space (s) is preferably sealed or can be sealed but alternatively may allow some fluid transfer in and / or out of the space (s). In a case in which the body is elongated, it is preferably suspended with the longitudinal axis of the body substantially subsurface. Each body can have at least one ballast tank. Preferably each body has a plurality of ballast tanks, each one can receive the ballast separately. If the bodies can receive ballast, the bodies can receive the adequate ballast in such a way that the balance can be controlled so that it depends on the strength and period of the waves. Thus the canifiness of amorfiguación of the movement of balancing can be adjusted according to the conditions. In addition, if loading or unloading from or to the vessel is required from another vessel, the risk of tampering can be adjusted to align the vessel with another vessel in a manner that facilitates loading and unloading. Preferably, each stabilizing assembly also has at least one fin projecting from the body or from each body. The fin increases the draft of the bodies as they move through the water. The size and shape of the fins is variable. For example the saleías can be recías or curves. In a modality at least one alefa is pivoiable in relation to the body or to each body to resist the movement of the body in an upward direction through the water) more than in the other direction (downward). This is useful because often it is required that there be more draft in the bodies when they move vertically upwards than when they move vertically downwards and the fins can be pivotable accordingly.

Alierously, the alloys may be shaped in such a way that there is more draft in one direction than in the other direction. Preferably each body is subspecially cylindrical and / or prismatic. In one embodiment, the body has a tubular shape. The body may have a circular section preferably circular. Alimentarily, the body may have a rectangular transverse section, for example a square cross section. Alimentarily, the body can have a triangular cross section. In one embodiment, one or both ends of the body are substantially conical. This is advantageous because it facilitates transport. The bodies can, for example, be attached to the container to be dragged below the water line to the desired position, where they can be fixed to the vessel at appropriate points. The conical exíremos facilitate the drag. The bodies may alternatively have hemispherical or rounded ends or any other form that facilitates dragging. Consideration should be given to the transfer of load from the suspension means to the rigidity of the vessel. In accordance with this, a load transfer structure is provided preferentially between the ship's address and the means of suspending to transfer the loads from the suspended means to the ship's address. In a preferred embodiment of the invention, the load transfer method is provided by one or more mounts to be attached to the vessel, to support the suspension means. The mounts can be attached at the edge of the boat's deck on the port or starboard side. The mounts can be fixed when the vessel is in port or at sea. The mounts are removed from the nacelle of the boat in such a way that the bodies are suspended from points that are slightly wider than the width of the boat itself. In the preferred embodiment of the invention only the vertical loads of the suspension means must be transferred and it is therefore preferred that only the vertical loads are arranged to be transferred from the suspension means. This can result from the nature of the suspension means (for example if the suspension means is an elongate flexible member), or from the nature of a coupling. The suspension means of the first stabilizer assembly can be connected to the suspension means of the second destabilizing assembly. The connection is preferably a structural connection made directly or indirectly. If done indirectly it is preferably done by means of an additional structure separated from the structure of the vessel. According to a second aspect of the invention there is provided an apparatus for reducing the movement of a vessel having: a first sizing assembly and a second sizing assembly: at least one submersible body at least partially hollow; and suspending means for suspending the or each body of the vessel, the first and second stabilizing assemblies are suitable to be placed in portions subconsciously opposite the vessel. Each body can have at least one weight ballast, preferably each body has a plurality of ballast tanks, each of which can receive the ballast separately. Preferably each stabilizing assembly further comprises at least one aleia projecting from each body. Even more preferentially, the at least one aleia can pivot in relation to each body to restrict the movement of the body in one direction rather than in the other direction. Advantageously, each body has a substantially cylindrical and / or prismatic shape. In one embodiment, the body has a circular cross section and preferably circular. In other modalities, the body has a cross-section of the recirculation, for example a square cross section. In another mode, the body has a triangular cross section. One or both ends of the body can be substantially conical, hemispherical or round. Esio facilitates the transporie by means of drag. The apparatus may also present one or more monitors attached to the vessel to support the suspension means. The mounts can be attached to the boat's edge of the boat on the port or starboard side. The mounts can be fixed when the boat is in the port or when it is in the sea. The mounts extend the entire width of the boat in such a way that the bodies are suspended from points that are slightly further apart than the width of the boat itself. This additionally stabilizes the boat. Preferably the suspension means of the first stabilizer assembly is connected to the suspension means of the second destabilizing assembly. That connection is preferably a structural connection made directly or indirectly. If done indirectly preferentially, it is done through an additional structure separate from the structure of the vessel. According to a third aspect of the invention, there is provided a submersible body in the form of at least one partially hollow tube, to reduce the movement of an aquatic vessel, which has: at least one lasing tank; and at least one projecting fin to increase the body draft through the water. Preferably the body has a plurality of lasers each ballasted separately. In one embodiment, the tube has a circular transverse section.

In another modality, the tube has a cross-sectional section, for example, a cross-sectional section. In other modality, the tube has a transversal cross-sectional section. One or both of the exubera of the tube can be subsinarily conical. Esio facilitated the transference of the fubos by means of arrasíre.

At least one or both ends of the tubes may be rounded or hemispherical or may have any other shape that facilitates transpiration by means of entrainment. The fin or each aleia can pivot in relation to the tube to restrict the movement of the body through the water in one direction rather than in another direction. According to a similar aspect of the invention, a method is provided to reduce the movement of an aquatic vessel consisting of: suspending at least two partially hollow bodies below the water level from the sides subjacently of the vessel. Preferentially the method in addition consists in adding lasíre to each body. It should be understood that in the earlier description in which a feature is described with respect to the invention, it may also be appropriate to employ it with respect to another aspect of the invention. Thus, for example, the method of the fourth aspect of the invention can be used with a vessel in any of the forms defined according to the first aspect of the invention.

DESCRIPTION OF THE FIGURES An embodiment of the invention will now be described with reference to the accompanying drawings in which: Figure 1 is a view of a boat that includes a stabilizer according to the invention; Figure 2 is a side elevational view of the vessel of Figure 1; Figure 3 is a front elevational view of the boat of Figures 1 and 2; Figure 4 is a plan view of a vessel having a first alternative stabilizing arrangement; Figure 5 is a side elevational view of the vessel of Figure 4; Fig. 6 is a plan view of a boat having a second alternate spraying arrangement; Figure 7 is a view in elevation of the boat of Figure 6; Figure 8 is a pillory view of a stabilizing tube; Figure 9 is a elevation view of the tube of Figure 8; Figure 10 is a cross-sectional view of a stabilizing tube having an alternative construction; Figure 11 is a cross-sectional view of a stabilizing tube having a second alternative construction; Figure 12 is a cross-sectional view of a stabilizing tube that has an alternative construction; Figure 13 is a graph showing the effect of the stabilizing arrangement on the degree and period of the rolling motion. DESCRIPTION OF THE INVENTION Figures 1, 2 and 3 show a boat 2 having a stern 4, a bow 6, a side to port 8, and a starboard side 1 0 and a deck 12. Suspended from the boat are four tubes 14, two tubes near port 8 and two tubes near starboard 10. One tube 14a on the port side is located near the bow of the vessel. A port side 14a tube is located near the stern of the vessel. A tube 14c on the starboard side is located near the bow of the boat. A 14d tube on the starboard side is located near the stern of the boat. Each tube 14 is suspended from the boat by means of two chains 16. The chains 16 of the opposite tubes 14a, 14c and 14b, 14 d are joined near the center of the cover 1 2. As shown in the drawings the tubes are They place with their longitudinal axes horizontally. Mounts 18 placed on the edge between the deck and port 8 and deck 12 and starboard 10, hold the chains 16. This ensures that the chains 16 remain outside the sides of the vessel even when it performs a certain rocking motion. Each tube is substantially cylindrical. Each tube includes a number of ballast tanks (not shown), which can be loaded and unloaded with ballast, allowing the mass of the tubes 14 to remain in the water. Each tube 14 also includes two horizontal fins 22. The horizontal fins 22 prevent the speed movement of the tubes 14 in the vertical direction. As the boat swings, port 8 and starboard 1 0 alternately lower and rise. When port 8 rises, the tubes on the port side 14a and 14b require moving upwards and the mass of the tubes and the projected aliases prevent upward movement. More particularly, the necessary upward acceleration of the tubes is limited by the inertia of the tubes, while the tubes and fins are also resistant to high-speed water travel. In a similar manner when starboard 10 rises, the tubes 14c and 14d of the starboard side require moving upwards and the mass of the tubes and the projected alloys prevent movement upwards. This reduces the swinging movement of the boat 2; the swing radius is reduced and the period of movement increased, that is, the frequency is reduced. The tubes, chains and mounts can be fixed to the boat in the port or at sea. The diameter and length of each tube is variable to suit the application. The material used to build the tube is variable and will depend on the desired mass of each tube. The mass of each tube affects the acceleration of the tubes through the water. The number of ballast tanks in each tube is variable and the tubes are designed to receive ballast on the deck so that the tubes can be swept into the water to facilitate transport. The cross section of the tubes is also variable (see figures 1 0 to 1 2). The tubes can be conical ends in order to facilitate transport. The length of the chains is also variable. The size and shape of the fins is variable and the fins can pivot in relation to the tube in such a way that the tube moves vertically upwards the projections are projected horizontally to prevent upward movement, but as the tube moves Downwardly, the flaps pivot inwards so as not to impede the downward movement. The size and shape of the alloys affected the velocity of the tubes from the water. In one embodiment, the tubes have a length of 40 m, with conical ends and 5 m in diameter. Each tube weighs 200 tons and presents ten separate lasir tanks. Each tube has two projected 75 cm fins, which extend along the entire tube and cones. The tubes can be suspended 25 m below the water level. Figures 4 and 5 show an alternative arrangement for the tubes in the boat. Esío is known as an asymmetric arrangement. In this case two tubes 14 are suspended near port 8 and one tube is suspended near starboard 10. A port side tube 14a is located near the bow of the vessel and the port rod 14b is located near the stern of the vessel. the ship. The tube on the sterilizer side 14c is located at the top of the ship. Of course there could alternatively be two tubes on the side of the ship and only one on the port side.

Figures 6 and 7 show an alternative arrangement for the tubes in the boat. This is known as ladder arrangement. In this case the two tubes 14 are suspended close to port 8 or two tubes are suspended close to starboard 1 0. A port side tube 14a is located near the bow of the boat and a tube on the port side 14b is located on the stern side of the vessel. Both tubes on the starboard side are located in the center of the boat, the second starboard side tube 14d is suspended below the first starboard side tube 14c. Obviously, there could be two tubes in the middle of the ship on the port side, one tube on the starboard side of the stern and one tube on the starboard side of the bow. Alternative arrangements are also contemplated that are not explicitly illustrated, for example, a double ladder arrangement that has two tubes to the side of the port side and that has two tubes in the middle of the starboard side. Figures 8 and 9 show the tubes 14 in greater detail. Each tube 14 has two horizontal fins 22 projecting from the tube 14. Each tube 14 has the lifting points 24 shown schematically in Figures 8 and 9. In the tube 14 shown in Figure 9 there are two lifting points 8 24, two on the upper side of the tube and two on the lower side of the tube . The two lifting points 24 on the upper side allow the chains 16 to join to suspend the tubes of the boat. The two lifting points 24 on the underside are only useful when the tube is used in the ladder arrangement shown in Figures 6 and 7. However, in many cases, it is advantageous that all tubes have four lifting points 24 of so that the construction of each tube is the same and each tube can be used in any application. Figures 1 0 and 1 1 show a tube 14 having a square cross section. Such a cross section gives the tube a greater wing through the water. In figure 10 the horizontal fins project from the side of the square tubes. In Figure 11, the horizontal alleles project from the base of the square tubes. Figure 12 shows an object 14 that has a triangular section. Such a cross section gives the tube a greater draft when it moves verícalmente up but reduced draft when it moves veríicalmenie downwards. As the boat swings, port and starboard alternately rise and fall. When low port, the tubes on the port side need to move down through the water. Therefore, it is advantageous if there is as little downward as possible possible. Unlike when port side ups, the tubes on the port side need to resist upward movement through the water. Therefore it is advantageous that there is the greatest possible draft upwards. Other transverse shapes can be considered and those shapes will have different effects on the speed and acceleration of the tubes in the water as the boat swings. It is particularly advantageous if the size and shape of the tubes take into account the use of the tubes in other applications. Additionally, the storage of the tubes should be considered. For example in the field of oil and gas maritime. The tubes can be stored horizontally on the cover of a stationary structure, or a boat or on the coast. Alternatively the tubes can be stored in the sea when they are not in use. They can for example be stored horizontally on the seabed, preferably with a caution buoy floating in the sea, or a group of tubes can be rotated in the vertical position, linked together and moored in the sea in a floating arrangement with parts of the tubes projecting up above the surface and submerged parts below the surface. When considering the effect of the stabilizing device on the rocking motion of the boat, there are two factors that must be considered: the frequency of the rolling movement and the amplitude of the rolling movement. The natural frequency of the rolling depends on the mass of the system, since the mass of the tubes increases, the natural period of the rolling movement of the boat increases. The amplitude of the roll depends on the damping forces applied to the system and as the damping force increases, the amplitude will decrease, that is the amplitude depends on the geometry of the tubes. Thus, as the diameter of the tubes and the size of the fins increase, the amplitude of the rocking movement of the vessel is reduced. Referring to Figure 13, the effect of the stabilizing device can be clearly observed. Figure 1 3 shows the amplitude of the roll as a function of the period of wave motion applied. The x axis shows the period in seconds and the axis and the RAO balance in degrees / m. The upper graph is the base case, this is the vessel without any stabilization device. It can be seen that the natural period of the vessel is close to 1 0 s. The average graph is the average case in which the vessel is provided with stabilization devices in which the tubes have a diameter of 3 m and the fins project 500 mm. It can be observed that the natural period of the vessel is close to 1 1 s. The lower graph is another case in which the vessel is provided with a stabilizer in which the tubes have a diameter of 5m and the alloys were projected 500mm. It can be seen that the naval period of the vessel is close to 12 s. Thus it can be seen clearly in Figure 13 that the effect of the stabilizing apparatus is to reduce the amplitude of the rocking motion of the vessel (that is, the peak of the curves = and to increase the period of the rocking motion of the vessel is reduced.

(This is the peak of the curves moves to the right in the x direction). The above description is simplified, and as mentioned before, there are many other variables that will affect the amplitude and period of the rolling movement, for example the transverse shape of the tubes and the size and shape of the fins. Although certain specific embodiments of the invention have been described, it should be understood that many variations are possible. In particular if the tubes 14 are not being used to stabilize a vessel, they can be subjected to a variety of additional uses. For example, a tube can float with its longitudinal axis in a horizontal position and be used as a buoy indicating a submerged mooring. Alternatively, it can be used as a floating tank to convey a structure and can be used after adding the appropriate ballast, for erecting a structure from the seabed or introducing a structure to the seabed.

Claims (57)

1. CLAIMS 1. A vessel comprising a first stabilizer assembly and a second stabilizer assembly, each stabilizer assembly comprising: at least one submersible body at least partially hollow; and suspension means for suspending the or each body of the vessel, the first and second stabilizing assemblies are suspended from substantially opposite sides of the vessel. 2. A vessel according to claim 1, in which the first stabilizing assembly has: a first submersible body but may have: a first partially hollow submersible body and a second partially hollow submersible body; first suspension means for suspending the first body of the vessel; and second suspension means for suspending the second body from the first body. 3. A vessel according to claim 1 or 2, wherein the second stabilizer assembly has: a first partially hollow submersible body and a second partially hollow submersible body; first suspension means for suspending the first body of the vessel; and second suspension means for suspending the second body from the first body. 4. A vessel according to any of the preceding claims having a third stabilizing assembly, the third stabilizing assembly having: at least one submersible body at least partially hollow; and means of suspension to suspend the or each body of the vessel. A vessel according to claim 4, in which the first stabilizer assembly is suspended near the bow of a vessel, the third stabilizer assembly is suspended near the stern of the vessel on each side and the second stabilizer assembly is suspended. suspended in the middle of the other side of the boat. 6. A vessel according to claim 4 or 5, wherein the third stabilizer assembly has: a first partly hollow submersible body and a second partly hollow submersible body; first suspension means for suspending the first body of the vessel; and second suspension means for suspending the second body from the first body. 7. A vessel according to one of claims 4 to 6, which has a fourth stabilizing assembly, the curial assembling stabilizer had: at least one submersible body at least partially hollow; and means of suspension to suspend the or each body of the vessel. 8. A vessel according to claim 7 in which the first stabilizer assembly is suspended near the bow of the vessel on one side, the second stabilizer assembly is suspended near the bow of the vessel on the other side, the vessel The stabilizer assembly is suspended near the stern of the boat on the first side and the fourth stabilizer assembly is suspended near the stern of the boat on the other side. 9. A vessel according to any one of the preceding claims in which the suspension means are capable of absorbing loads of alias voltage. A vessel according to claim 9 in which the suspension means is capable of supporting tensile loads of more than one hundred times the compression loads it is capable of withstanding. eleven . A vessel according to claim 9 or 10 in which the suspending means consist of elongate flexible members.
2. 2. A vessel according to claim 1 wherein the elongate flexible members are chains. 13. A vessel "according to any of the preceding claims in which each body has an elongated shape and has a cross section greater than 4 m2. 14. A vessel according to any of the preceding claims in which each body has one or more spaces closed or that can be closed that has a combined volume greater than 50 m3. 1 5. A vessel according to any of the preceding claims in which each body had at least one fanf of lasfre. 16. A vessel according to claim 7 in which each body has a plurality of lasers that can be lased separately. 17. A vessel according to any of the preceding claims in which each stabilized assembly has at least one fin projecting from the body or from each body. 18. A vessel according to claim 17 in which at least one fin can pivot with respect to the body or to each body, to restrict the movement of the body upwards through water rather than downwards 1 9. A vessel according to any of the preceding claims in which each body has a substantially prismatic shape. 20. A vessel according to any of the preceding claims in which each body has a circular cross section preferably circular. twenty-one . A vessel according to one of claims 1 to 19, wherein each body has a rectangular cross section. 22. A vessel according to one of claims 1 to 1 9, wherein each body has a square cross section. 23. A vessel according to one of claims 1 to 1 9, wherein each body has a triangular cross section. 24. A vessel according to one of claims 19 to 23, in which one or both ends of each body is substantially conical. 25. A vessel according to any of the preceding claims, which also had one or more mounts fixed to the vessel to sustain the means of suspension. 26. A vessel according to any of the preceding claims in which the suspension means of the first stabilizer assembly is connected to the suspension means of the second scaler assembly. 27. A vessel according to any one of the preceding claims in which only the verical charges are placed to be transferred from the suspension means to the vessel. 28. An apparatus to reduce the movement of a vessel that had a first assembly and a second destabilizing assembly: at least one submersible body at least partially hollow; and means of suspension for suspending the or each body of the vessel, the first and second delimiting assemblies are suitable to be placed in portions substantially subjacent to the vessel. 29. An apparatus according to claim 28 in which each body has an elongated shape and has a cross section greater than 4 m2. 30. An apparatus according to claim 28 or 29 in which each body has one or more closed or closed spaces having a combined volume greater than 50 m3. 31 A set according to claim 30 in which each body had at least one ballast band. 32. An apparatus according to claim 31 in which each body has a plurality of ballast tanks which can be ballasted separately. 33. An apparatus according to claims 30 to 32 in which each stabilized assembly has at least one fin projecting from the body or from each body. 34. An apparatus according to claim 33 in which at least one fin is pivotable in relation to the body or to each body to restrict movement of the body through the water in one direction rather than in another direction. 35. An apparatus according to claims 30 to 34 in which each body has a substantially prismatic shape. 36. An apparatus according to claims 28 to 35 in which each body has a preferably circular round cross section. 37. An apparatus according to claims 28 to 35 in which each body has a rectangular cross section. 38. An apparatus according to claims 28 to 35 in which each body has a square cross section. 39. An apparatus according to claims 28 to 35 in which each body has a triangular cross section. 40. An apparatus according to claims 35 to 39 in which one or both ends of each body is substantially conical. 41 An apparatus according to claims 30 to 40 further comprising one or more mounts fixed to the vessel for holding the suspension means. 42. An apparatus according to claims 30 to 41 wherein the suspension means of the first stabilizer assembly is connected to the suspension means of the second stabilizer assembly. 43. A vessel including a stabilizing apparatus according to one of claims 30 to 42. 44. A submersible body in the form of at least one partially hollow tube, to reduce the movement of a watercraft, having: at least one tank of water. ballast; and at least one projecting fin to increase the body draft through the water. 45. A body according to claim 44 in which each body has an elongated shape and has a cross section greater than 4 m2. 46. A body according to claim 44 or 45, in which each body has one or more closed or closed spaces having a combined volume greater than 50 m3. 47. A body according to claims 44 to 46, wherein the body has a plurality of ballast tanks, each individually ballasted. 48. A body according to claims 44 to 47, wherein the tube has a preferential round circular cross section. 49. A body according to claims 44 to 47, in which the tube has a rectangular cross section. 50. A body according to claim 49, wherein the tube has a square cross section. 51 A body according to claims 44 to 47, in which the tube has a triangular cross-section. 52. A body according to claims 44 to 51, in which one or both of the exiros of each body is subsanially tapered. 53. A body according to claims 44 to 52, in which the or each aleia is pivotable in relation to the body or to each body to resist the movement of the body through the water in one direction more than in another direction. 54. A stripping apparatus having a body according to any one of claims 44 to 53. 55. A method for reducing the movement of a watercraft consisting of: suspending at least two bodies partially in holes below the water level from sides subsidentally, opposites of the boat. 56. A method according to claim 55 which further consists in lasering each body. 57. A method according to claim 55 or 56, in which the vessel conforms to any of claims 1 to 27 or 43. RESU MEN A vessel (2) had a first stabilizer assembly (14) and a second stabilizer assembly, each stabilizer assembly had at least one submersible body at least partially hollow; and suspension means (16) for suspending the body or each body from the vessel, and the first and second separating assemblies are suspended from mutually subjacent sides of the vessel. The alloys (22) are provided on the weakening assembly.