US3785511A

US3785511A - Anti-pounding device mounted on a boat for maintaining a cable at a given level above an underwater bed

Info

Publication number: US3785511A
Application number: US00231237A
Authority: US
Inventors: P Bonnamy; J Mugneret
Original assignee: Compagnie Francaise des Petroles SA
Current assignee: Total Compagnie Francaise des Petroles SA
Priority date: 1971-03-02
Filing date: 1972-03-02
Publication date: 1974-01-15
Anticipated expiration: 1991-01-15
Also published as: NO147509C; GB1378713A; NO147509B; JPS5649792B1; CA961477A; NO782753L; NL7202757A; NL153969B

Abstract

An anti-pounding device is provided to prevent the relative movement generated by waves to be transmitted to a tool. A system of pulleys is arranged on a carriage that is fixed to a guide path. A power winch is connected through a pulley to the carriage and accordingly, to a suspended tool to eliminate the relative movement of the boat. The arrangement of pulleys with a movable support can be connected to a tower or crane in a similar fashion with a compensation bar.

Description

[ Jan. 15, 1974 ANTI-POUNDING DEVICE MOUNTED ON A BOAT FOR MAINTAINING A'CABLE AT A [56] References Cited UNITED STATES PATENTS GIVEN LEVEL ABOVE AN UNDERWATER BED 75 inventors; Philippe Bonnamy, 2,854,154 9/1958 Hepinstall.............................

Boulogne-Billancourt; Jean A. 2 5 5 et Mugneret, carrieres s seine, both of a mi et a Primary Examiner-Frank E. Werner Compagnie Francaise Des Petroles, Attorney-Richard C. Sughrue et al.

e m a r. MW F m m r a F Di Me e n .w 5 S A 1 5 .l

[57] ABSTRACT An anti-pounding device is provided to prevent the [22] Filed: Mar. 2, 1972 App! 231,237 relative movement generated by waves to be transmitted to a tool. A system of pulleys is arranged on a car- Foreign Application Priority Mar. 2, I97! [30] D m riage that is fixed to a guide path. A power winch is France connected through a pulley to the carriage and accordingly, to a suspended tool to eliminate the relative movement of the boat. The arrangement of pulleys with a movable support can be connected to a tower France Feb. I7. 1972 or crane in a similar fashion with a compensation bar.

22 Claims, 12 Drawing Figures 1 ANTI-POUNDING DEVICE MOUNTED ON A BOAT FOR MAINTAINING A CABLE AT A GIVEN LEVEL ABOVE AN UNDERWATER BED BACKGROUND OF THE INVENTION 1. Field of the Invention The invention relates to an anti-pounding device capable of being installed on a low tonnage boat for maintaining a cable, generally a tool holding cable suspended from said boat in any predetermined position with respect to the level of the underwater bed above which the boat is located.

2. Description of the Prior Art All known anti-pounding devices are based on the principle of securing the movement of the suspended tool holding cable by varying the length of a portion of the taut anchoring cable, said portion being located between a fixed point with respect to the underwater bed to which the cable is connected and the pulley supporting this cable fixed to the boat. This principle disclosed in the U.S. Pat. No. 2,809,435 granted to Nicolson has given rise to numerous embodiments, one of the most compact and efficient of which consists in supporting the cable holding the tool which is to be maintained at a given level, by a first pulley situated perpendicular to this point and in supporting the anchoring cable by another pulley situated perpendicular to the anchoring point, the two pulleys being supported by a single assembly. By exerting a certain vertical pressure on this assembly, for example, by means ofajack, the anchoring cable may be kept constantly taut and the tool holding cable secured by varying the length of the portion of the anchoring cable between one of the ends of the anchoring cable and the pulley supporting it mounted on said assembly.

In this way, the cable and the assembly of pulleys supporting them were kept in constant vertical alignment so that it was necessary to use a fairly large vertical frame to allow the assembly to move on this frameat a height at least equal to that of the swell. Such a structure made it impossible to mount an anti-pounding device at the front or rear end of theship, theonly boats on which the device could be installed being platforms specially conceived for this purpose where the vertical frame was located in the center, or boats with a well in the middle of the hold.

,Thus, all the known devices have the disadvantage of being subject to considerable stresses, in particular as a result of the weight of the holding cable, the slightest roller making itself felt with the assembly of pulleys in the elevated position.

In addition, by virtue of their structure, none of the existing devices allow easy disconnection of the cable holding the anti-pounding device, which is a considerable disadvantage when the tool has frequently to be brought on board the boat, and this represents a weighty and awkward load.

SUMMARY OF THE INVENTION The main object of the invention is an anti-pounding device for any type of boat comprising a tool holding cable controlled by a winch and an anchoring cable secured at one of its ends at a fixed point with respect to the underwater bed and an assembly bearing a pulley,

supporting the anchoring cable and a pulley supporting the tool holding cable, said device being characterized in that it comprises a. at least one means for guiding and deflecting the anchoring cable secured with respect to the boat and causing said cable to move away from the vertical,

b. means for guiding and deflecting the tool holding cable secured with respect to the boat and causing said cable to move away from the vertical,

0. a nonvertical track for the displacement of said assembly bearing the pulley supporting the anchoring cable and tool holding cable,

d. a drive means secured to the rear of the boar exerting a force on the assembly and comprising at least one horizontal part.

Apart from its simplicity this system allows numerous problems to be solved.

In fact it removes the need to provide vertical gantries on which fairly heavy loads, for example, of one to two tons, are displaced, thus rendering them subject to loss of balance, particularly in the event of rollers which affect the stability of the boat.

It is thus possible to considerably reduce the structure of the anti-pounding device and to use boats oflow tonnage by assembling the device according to the invention, preferably at the rear of the boat, the anchoring cable no longer being fixed plumb with the center of the boat, but slightly without the contour of the boat.

By fixing the two means for deflecting and guiding the tool holder cable and the anchoring cable on brackets at the rear of the boat and by using a horizontal guide track for the assembly bearing the pulleys each supporting a cable, the loss of energy resulting from the need with the older devices to reassemble or constantly support the weight of the pulley support assembly towards the top of vertical frame is eliminated.

Another object of the invention is a device of this type comprising in addition a detachable member which is normally disposed on said support pulley assembly, said member being integral with the pulley supporting the tool holding cable. As a result of the horizontal disposition of the guide track for the pulley assembly supporting the cables, such a device permits the easy disconnection of the tool holder cable from the anti-pounding device. To immobilize the detachable member an element fixed in respect of the deck of the ship may be interposed on the path of the detachable member, thus rendering the support cable and its tool integral with the ship and not with the anti-pounding device.

The very structure of the anti-pounding device allows the means for deflecting and guiding the support cable to be mounted on a displaceable bracket, for example, along a vertical girder, thus facilitating access to the tool secured at the end of the support cable. The tool may be brought without danger onto the deck of the ship as soon as the cable has been disconnected from the anti-pounding device. It will be noted that when the tool has been immobilized on the deck of the ship the means for deflecting and guiding the support cable is only subject to a slight strain and consequently only exerts a slight stress at the base of the girder even when the upper part of the latter is hoisted up and in spite of the movements of the ship.

Another object of the invention is an anti-pounding device of the type described above with respect to the main object, the structure of which facilitates its use even on gantries disposed on board ship or on a marine drilling platform, this device being characterized in that it comprises a vertical plane of symmetry with respect to the forces being exerted on it, rollers with horizontal shafts and perpendicular to the plane of symmetry being situated at its lower part and at least a plurality of lateral guide rollers on either side of the symmetry plane, at its lower part, the lower rollers resting on a lower rolling path and the guide rollers cooperating with an upper guide path parallel to the first.

This device has the advantage of being more compact and more capable of resisting the forces of vertical stresses which may be exerted on the base of its chassis when this is raised, particularly when it is raised by the boom of the crane. As only one guide path rests on the chassis the device is no longer acted on by the stresses of differing intensities causing increased inertia of the system by virtue of the forces brought into play.

Another object of the invention is a structure of this type characterized in that the said upper and lower paths of the carriage are part of a chassis integral with the vertical tower of a crane and independent of the boom, the return pulley of the handling cable being disposed in said plane of symmetry.

Such a structure allows both the elimination of any stress on the part of the boom on the device and considerable reduction of the inertia of the carriage.

The importance of this assembly is to be able to use the anti-pounding device not only on boats but also on drilling platforms and ships having to move materials and personnel from other boats. It is particularly difficult to load these boats as soon as the effect of the swell can be felt and it becomes impossible if there is to be some sort of safety restriction as soon as the troughs of the waves reach 3 meters. The problem of loading and unloading these is easily resolved by using the device described above. In fact, it is sufficient to lower the anchoring cables of the anti-pounding device provided on the crane to the level of the supply ship to connect the ends of the cables to a compensation bar which is secured to the deck and to stretch the cables by means of the anti-pounding device to obtain cables serving as guide means for the loads which are placed in a scoop hooked to the handling cable of the anti-pounding device. The materials and personnel may then be unloaded without danger of collison regardless of the swell, the handling cable being secured with respect to the deck of the boat as soon as the winch controlling the cable is stopped.

Other advantages and features of the anti-pounding device will be disclosed in the following description given with reference to the attached drawing which shows, by way of nonlimitative example, an embodiment of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagrammatic view in perspective of the anti-pounding device,

FIG. 2 is a diagrammatic view of the guide chassis of the mobile carriage of the device shown in FIG. 1,

FIG. 3 is a diagrammatic view in perspective of a girder supporting the mobile deflecting means of the tool holding cable,

FIG. 4 is an elevated view ofa device for immobilizing the detachable member of the pulley assembly supporting the tool holding cable and the anchoring cable,

FIG. 5 is a plan view of the device of FIG. 4,

FIG. 6 is a diagram of the principle of a variant of the device according to FIG. 1,

FIG. 7 is a diagram of the anti-roll assembly of anchoring cables of the device according to FIG. 1,

FIG. 8 is a diagrammatic plan view of a device for tightening the anchoring cables of an anti-pounding device,

FIG. 9 is a diagrammatic view in perspective of the new structure adapted for the addition of a crane,

FIG. 10 is a view of the structure according to the direction of X of FIG. 9,

FIG. 11 is a diagrammatic view of the anchoring cables while they are being stressed by the anti-pounding device, and

FIG. 12 is a diagrammatic view corresponding to that of FIG. 11 after stopping the anti-pounding device.

DESCRIPTION OF THE PREFERRED EMBODIMENT The anchoring of the anti-pounding device is effected preferably with the aid ofa pair of cables 1 whose ends are integral with a piece 30 secured with respect to the underwater base. This may be, for example, any part extending at the head of an oil well 14 which it may be necessary to enter to carry out work with the cable. The same anchoring cables 1 may be used for handling all relatively heavy loads.

These cables pass into the mouths of the pulleys 3 whose role is to guide and deflect these cables in such a way that they are constantly stretched in a direction vertical of their lower end at the height of the pulleys 3 and stretched horizontally by the pulley 3 having the small wheels 6 provided with stops which are not shown in the drawings for reasons of clarity.

The tension of the cables 1 is obtained by means of the assembly 5 bearing the pulleys 4, said assembly being mounted on wheels 31, guided by the rails 32. A cable 12 secured at the point of attachment 52 and wound on the constant tension winch ll, exerts a tractive force on the cables 1 by means of the pulleys 4.

When the boat may be small, for example 15 m in length, is subjected to the action of the swell, and the boat remains practically on the vertical of the place where the anchor is, the carriage 5 displaces itself horizontally independent on the vertical movement of the swell. FIG. 2 shows means of guiding the carriage 5 on the rails 32. A chassis 5a, integral with the carriage 5, also comprises bearer wheels 31, lower wheels 31a, preventing inopportune rocking of the chassis about the horizontal axis. The lateral guide wheels 31b also prevent the carriage from slipping out laterally under the effect of a horizontal force perpendicular to the rails.

It will be noted that as a result of the assembly of pulleys 4, the displacement of the carriage 5 is only equal to half the vertical displacement of the boat. This displacement could obviously be reduced even more by further pulleys.

Mounted on the same assembly 5 is a pulley 10 which, by virtue of the displacement of this assembly, makes it possible to increase or reduce the available length of cable 7 unwrapped originally from the winch l5 assumed momentarily blocked. The cable 7 first passes about the pulley 8 and then the pulley 10 to be deflected finally by the pulley 9 from a horizontal direction to a vertical direction. The assembly 2 ensures guiding of the tool secured at the end of cable 7, inside this assembly, the arms 2a being guided on the cables 1. Although the assembly 2 which is shown has been chosen to show how such a system can cooperate with the wellhead 14, it is obvious that this assembly may be replaced by any other as well as by any type of load or too]. As the assembly 2 is already known and is not a part of the invention it will not be described.

It will be noted that as the pulleys 4 and 10 are mounted on the same assembly the distance between the underwater base and any point on the vertical sections of the

cables

1 or 7 remains constant. The winch may be controlled at will and the end of the cable 7 may be lowered to any desired level and held there irrespective of the vertical displacement of the boat due to the swell.

The .small wheels with stops may be used to regulate the mean position of the carriage 5 independence on the tides.

The device that has just been described is particularly suitable for disconnection of the support cable 7 from the anti-pounding device. In fact, according to a first embodiment of the device, the carriage 5 may consist of two independent parts, the separation of which is shown diagrammatically by means of the perforated lines 34. The rear part onto which the attachment 33 is secured moves forward the part bearing the pulley 10 under the influence of the traction exerted by the cable 12 while the weight of the cable 7 and the load 2 constantly forces the front part of the carriage against the rear part.

When it is wished to bring the tool or the load on board, it suffices to block the front part of the carriage when this has been brought forward by any suitable means, for example, catches, wedges, removable abutmcnts, or an anti-return device. This being so, the tool 2 may be brought back onto the deck of the ship without it being subjected to any kind of displacement since the pulley I is pulled neither to the front nor the rear of the boat.

Likewise, to facilitate the unloading of the tool 2 on the deck of the boat, the

pulleys

8 and 9 may be disposed on a support 25, FIG. 3, displaceable on a vertical girder 26. A cable 77 secured to the support 25 and passing about the pulley 38 allows the support 25 to be mounted along the girder by means of a manual winch 27. In this way, each time it is wished to bring on deck a package or a tool, it suffices to raise the

pulleys

8 and 9 to a certain height so as to create a sufficient space between the rear part of the boat and the pulleys to allow the tools or packages to be placed on deck.

According to another embodiment of the invention, the tool holding cable 7 may also be disconnected from its anti-pounding device by using a support assembly of pulleys 4 and 10 such as the one shown at in FIG. 1, but consisting of a carriage with a single adjacent part. To this end, the pulley is mounted on a shaft 29, FIGS. 4 and 5, resting on a neck 24 of each side plate 35 integral with the carriage 5.

A work bridge 17 with a central passage for the free circulation of the side plates 35 is provided with a series of perforations 19 in which the lugs 18 of a trestle 16 mayengage. This trestle supports a shaft 21 serving as pivot to a lever driving the arm 3, the ends of which terminate in forks 22. An abutment 23 limits the downward course of these arms at a point where the forks are on the same level as the shaft 29 of the pulley 10. In this way, when the carriage 5 moves toward the rear of the boat, the shaft 29 of the pulley 10 is stopped by the fork 22 and disengages itself fromthe notches 24 of the side plates 35. The dimensions of the trestle 16 are such that the carriage 5 and the side plates 35 pass freely below the shaft 21 and between the side plates 36 and the trestle 16. As a result, the forks 22 disconnect the pulley 10 from the carriage 5. Then the operator merely has to lower the lever 20 as shown in perforated lines in FIG. 4 to prevent the pulley being taken up again by the notches 24 of the side plates 35 supported by the carriage 5. The equilibration of the lever 20 allows the pulley 10 to be kept hooked up in the upper position shown in FIG. 4.

Thus, the horizontal movement of the carriage 5 provides a convenient and efficient means for connecting or disconnecting at will the cable 7 bearing the load of the anti-pounding device.

It is obvious that numerous modifications may be applied to the various elements which have been described. In particular, the anti-pounding device may be assembled on the single platform 13 serving as a frame. This may possibly be provided with slide blocks to facilitate the transport of the unit and make it particularly simple to install. Although according to a preferred embodiment of the invention the platform 13 is horizontal, certain boat structures on which it is mounted may involve assembly on slopes of varying degrees. In consequence of this, the sides of the cable may be inclined accordingly.

Likewise, when for lack of space, for example, the means described above for the disconnection of the cable supporting anti-pounding device cannot be used, a simple stretching device 41, FIG. 6, may be added to cable I, and in addition, a locking device 43 may be used.

When desiring to rest the anti-pounding device, the carriage 5 may be blocked in any position and the stretching device 41 unlocked. As stretching devices are well known, it is not necessary to describe them. However, according to a preferred embodiment, the pulleys of the stretching device are disposed adjacent to the small wheels 6.

As far as the constant tension winch 11, FIG. I, is concerned, this may be replaced by a jack 42. FIG. 6, pushing back the pulley supporting carriage 40. The secondary pulley means may be used to reduce the force of the carriage.

The small wheels 6 may then be replaced by constant tension winches, the action of which is normally stopped by simply blocking the cable adjacent to them. When it is desired to rest the anti-pounding device, it suffices to block the carriage 5 in any position and to free the cable 1, adjacent to these winches. As a result, in spite of the immobilization of the carriage 5, the cables l are always stretched by the constant tension winches, even in the case of considerable rolling of the boat. If only the small simple wheels 6 are used, the effects of rolling may be further reduced by mounting the pulleys 4 on a compensation bar 37 articulated on a vertical shaft 38 integral with a carriage 39, as shown in FIG. 7. In this version, the pulleys 4 have been mounted on vertical shafts and secondary pulley systems may be provided if desired.

The anti-pounding carriage 101 shown in FIG. 8 is acted on by a jack 102 supplied by the accumulator 103. For this purpose, the end of the shaft 104 of the jack bears a pulley 105 for stressing the cable 106 passing about the return pulley 107, the ends of the cable being secured to the carriage 101 by the attachment 108 and to a fixed point 109 on the boat 110 on which the anti-pounding device rests by means of attachment 111. The anchoring

cables

112 and 1 13, the lower ends of which are anchored at the bottom of the sea, pass respectively about the pulleys 114 and 115 integral with the carriage 101 and then about the return pulleys 116 and 117, then 118 and 119, before being wound on the

winches

120 and 121. Between the return pulleys 116 and 118 and between the

pulleys

117 and 119, tension pulleys 122 and 123 have been mounted, the supports of which 124 and 125 are acted on by the rubber shock absorbers shown in diagrammatic form at 126 and 127 and secured to the chassis at 128 and 129. The

ramps

130 and 131 serve as guide means for the

supports

124, 125.

So as not to overload the drawing, a pulley integral with the carriage 101 has been omitted about which passes the intervening cable connected to the handling control winch by means of a return pulley similar to 116 or 118, the other part of the handling cable being suspended by a pulley similar to

pulleys

132 and 133. The carriage can obviously support several pulleys varying the length of the vertical parts of the handling cables which they are supporting.

In the structure which is an object of the invention and which is shown in FIGS. 9 and 10, the antipounding device is mounted on a chassis comprising two

longitudinal tracks

134 and 135 serving as guide means for the carriage 136. In the example shown, this latter comprises essentially two

vertical plates

137 and 138 provided with bearing supports 139 for the horizontal roller shafts 140 disposed on either side of the guide tracks 134 and 135. The horizontal shafts disposed between the vertical plates at the lower and upper part of the carriage bear vertical rollers 141. Thus, the vertical shaft of the carriage 136 rolls in a vertical plane containing the return pulley 142 of the handling cable 143. The latter passes about the return pulley 159 before being wound on the control winch 150.

Two return pulleys 144 and 145 with vertical shafts borne by the

support

146 and 147 receive the sides of the anchoring

cable

150 and 151 situated on the side of the suspended part and lead the cables to the inclined return pulleys 148 and 149. The anchoring cables are wound on the

winches

152 and 153, respectively. These winches serve to regulate the mean position of the carriage in its course along the

tracks

134, 135. The jack acting on the carriage 136 is similar to that shown in FIGS. 8 and 9 and is not represented. Only its control cable 154 is partially shown.

Such a structure is advantageous when mounted on a crane, more particularly a crane of the type represented by 115 in FlGS. 11 and 12.

The unit is then assembled on a block 158, the central tower 156 supporting in an independent manner the anti-pounding system on the one hand and the boom 157 of the crane on the other hand so as to prevent the flection stresses of the crane from being transmitted to the

guide rails

134 and 135 of the carriage. The structure 172 resting on the central tower 156 which is equipped in the known way so as to be capable of pivoting the unit 360 about a vertical axis, is provided with rear suspension cables 173 connected to the block 158 supporting the winch 160 and the antipounding device as well as

suspension cables

174 and 175 intended to support the boom 157. This purely diagrammatic representation is only intended to illustrate the main feature of the crane which is the absence of reaction between the flection stresses to which the boom is subjected and the guide rails of the carriage of the anti-pounding device. The handling cable 143 is controlled in this case directly by the control winch of the crane designated by 160. The jack acting on or locking the carriage 136, the

winches

152, 153, controlling the length of the anchoring

cables

150, 151 as well as the handling control winch 160 are controlled from the control cabin 161.

In the example shown, the crane 155 is situated on a marine drilling platform 162 and is used for lowering and raising materials and work crews on board supply ships, such as 163, regardless of the swell. For this purpose, a compensation bar 164 which is connected to the anchoring point on the deck of the ship is fixed to the ends of the

cables

150 and 151. When the antipounding device has been rendered inoperative to release the

cables

150 and 151, the swivelable pulleys 166 and 167 for the anchoring

cables

150 and 151 and 168 for the handling cable 143 make it possible to deflect the

cables

150 and 151 during the rotation of the boom 157, as shown in FIG. 12. In addition, as the compensation bar unit 164, as shown in FIG. 12. In addition, as the compensation bar unit 164, the anchoring

cables

150, 151 and the swivelable pulleys 166, 167 form an ariculated parallelogram, when the antipounding device is rendered inoperative, as in the case of FIG. 11, the anchoring

cables

150, 151 remain parallel irrespective of the rolling, pitching and swinging movements of the ship.

[t is thus possible to attach to the handling cable 143 a scoop 169 which is guided by the

cables

150 and 151, by providing the scoop with two

vertical tubes

170 and 171 inside which slide the

cables

150 and 151.

As the handling cable can deposit on the platform 162 the material transported, for example, the scoop 169, the anchoring cables no longer have any use so that they do not have to be kept taut which means that a device such as the one represented under references 122 to 131 in FIG. 8 does not have to be incorporated.

This type of equipment renders the operation of lowering and raising staff or materials particularly simple.

After attaching the compensation bar 164 to the

cables

150 and 151 serving as guides for the scoop 169 supported by the cable 143, the circuit of the jack of the anti-pounding device is put under pressure until the carriage 136 reaches the middle of its course. The

cables

150 and 151 are then lowered with the compensation bar 164 which is attached to the deck of the ship. The

cables

150 and 151 are then stressed and their length is adjusted by means of the

winches

152 and 153. The scoop 169 and the

cables

150 and 151 are then in the position shown in FIG. 11. The jack is then freed so that the carriage 136 abuts in front, i.e., next to the upright 176, FIG. 9, so that the

cables

150, 151 become slack. After rotating the crane to the right with respect to the control cabin 161, the

cables

150 and 151 move into the free space between the

mobile bridges

177 and 178, the plane passing through the

tubes

170 and 171 becoming practically parallel to the opposing edges of the

bridges

177 and 178. The bridges may be brought together and the scoop deposited thereon for the purpose of taking on materials and staff. After unloading the scoop, rotating the crane in the opposite direction and reconnecting the hydraulic circuit controlling the jack of the anti-pounding device, the movement of the scoop again becomes dependent on the movement of the boat and the placing of the scoop on the deck of the boat is carried out smoothly.

By equipping the crane in this way and disposing it on board platforms and floating barges, it may also be used to carry out any desired operation on the seabed when it is necessary to avoid any movement of the tool attached to the cable 143 with respect to the seabed.

What is claimed is:

1. An anti-pounding device to prevent relative movement generated by waves on a boat comprising a tool cable, a first pulley for the tool cable, a winch controlled tool supported by the tool cable, an anchoring cable secured at one of its ends at a fixed level with respect to the seabed, a second pulley supporting the anchoring cable, a single, movable assembly means mounting the first and second pulleys for moving them jointly and in unison, at least one means for guiding and deflecting the anchoring cable secured with respect to the boat and causing said anchoring cable to move away from the vertical plane, means of guiding and deflecting the tool holding cable secured with respect to the boat and causing the cable to move away from the vertical plane. a nonvertical track for the guidance and displacement of said single assembly means and thereby the joint displacement of the pulleys supporting the anchoring cable and the tool holding cable, and a drive means fixed to the deck of the boat exerting a force on said single assembly means and composed of at least one horizontal part so as to stretch said cables.

2. A device as claimed in claim 1, further including a detachable member mounted on said pulley support assembly means, said member being integral with the first pulley supporting the tool cable.

'3. A device as claimed in claim 2, comprising in addition a general frame on which rests the displacement track of said assembly means.

4. A device as claimed in claim 3, in which the means for guiding and deflecting the tool holding and anchoring cable are composed of pulleys which are connected to the boat by means of the general frame.

5. A device as claimed in claim 4, in which the means for guiding and deflecting the tool holding cable includes two pulleys, a displaceable support, a vertical girder secured with respect to the boat and means for fixing the support on the girder at any desired level.

6. A device as claimed in claim 2, in which the pulley assembly means comprises two parts mobile with respect to each other, the one supporting the anchoring cable second pulley andthe other supporting the first pulley of the tool holding cable, said drive means exert ing a stress at constant tension on the part of the assembly supporting the pulley of the anchoring cable, the other part of the assembly being disposed between said drive means and the part-of the assembly supporting the second pulley of the anchoring cable.

7. A device as claimed in claim 6, in which said drive means is a constant tension winch.

8. A device as claimed in claim 6, in which said drive means is a jack.

9. A device as claimed in claim 2, in which the pulley assembly means comprises two side plates each supporting one end of the shaft of the support cable pulley,

each of the ends of the shaft of the pulley resting in a suitable notch in the supporting side plate.

10. A device as claimed in claim 9, further including a mobile fork and mobile lever, the shaft of the first pulley supporting the tool holding cable has two sections each cooperating with the mobile fork, said fork being integral with and controlled by the mobile lever capable of taking up two positions, one in which the fork is positioned on the directional course of the shaft of the pulley of the tool holding cable the other of which is positioned outside this directional course.

1 l. A device as claimed in claim 10, further including another fork, a trestle and a control lever, in which the assembly of the support arms of the forks and their control lever is mounted on a trestle displaceable along a path parallel to the path of the pulley assembly means, and a path securing means for maintaining said trestle in position when the shaft of the pulley supporting the tool holding cable is picked up by said forks.

12. A device as claimed in claim 1, in which the anchoring cable is connected to the boat and including small wheels with stops so as to be able to regulate the length of the anchoring cable depending on the level of the surface of the water with respect to the seabed.

13. A device as claimed in claim 1, comprising in addition a device for tightening the anchoring cable and a controlling device for the cable for the purpose of controlling its operation.

14. A device as claimed in claim 1, further including controllable blocking means and a constant tension winch in which the anchoring cable is connected to the boat by controllable blocking means, each of the ends opposed to those acting as their anchorage on the seabed being wound on a constant tension winch.

15. A device as claimed in claim 1, in which the pulley support assembly means comprises a frame supporting a compensation bar with a vertical axis and two pulleys each bearing an anchoring cable, each of the two pulleys being disposed at one of the ends of said compensation bar.

16. A device as claimed in claim 1, further including a crane having a tower, a second anchoring cable and a compensation bar, the anchoring cable being returned by pulleys disposed on the boom of the crane, the end of each anchoring cable being fixed to the ends of the compensation bar.

17. An anti-pounding device as claimed in claim 16 in which the assembly means for carrying the pulleys comprises a carriage means having a plane of vertical symmetry, rollers with horizontal axes perpendicular to. the plane of symmetry situated at its upper part on either side of the plane of symmetry, the lower rollers resting on a lower rolling path and the guide rollers cooperating with an upper guide path parallel to the first, these paths being situated in the plane of symmetry of the carriage means.

18. An anti-pounding device as claimed in claim 17, further including a traction cable and a handling cable, a pulley situated in the plane of symmetry of the carriage means is connected to the handling cable, a jack transmits a force by a cable in a parallel direction to the rolling part of the carriage means and passing by way of the shaft of the return pulley of the handling cable, the return pulley of the anchoring cables being situated in the plane by way of the traction cable of the carriage means controlled by the jack and by the axis of the return pulley of the tool holding cable.

21. An anti-pounding device as claimed in claim 20, in which each of the anchoring cables passes through a tube integral with the handling cable and a scoop.

22. An anti-pounding device as claimed in claim 21, in which the winch controlling the handling cable is the control winch of the crane, the device being disposed on the crane so as to be rotated at the same time as the boom.

"UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3, 785, 511 Dated January 15, 1974 Inventor(s Philippe J. F. BONNAMY et a1 7 It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 2, line 12 after "of the delete "boar" and insert boat Column 4, line 42 after boat insert which Column 6, line 44 after "42 delete and insert Column 8, lines delete In addition, as the compensation bar 26-27 unit 164, as shown in Figure 12.,

delete "ariculated'Vand insert articulated line 30 Signed and sealed this 9th dayof J u1y'1974.

(SEAL) Attest:

McCOY M. GIBSON; JR. C. MARSHALL DANN Attesting Officer 1 Commissioner of Patents =ORM PC4050 (10-69) USCOMM-DC 60376-P69 u.s. GOVERNMENT PRINTING OFFICE I9" 0-866-334,

Claims

1. An anti-pounding device to prevent relative movement generated by waves on a boat comprising a tool cable, a first pulley for the tool cable, a winch controlled tool supported by the tool cable, an anchoring cable secured at one of its ends at a fixed level with respect to the seabed, a second pulley supporting the anchoring cable, a single, movable assembly means mounting the first and second pulleys for moving them jointly and in unison, at least one means for guiding and deflecting the anchoring cable secured with respect to the boat and causing said anchoring cable to move away from the vertical plane, means of guiding and deflecting the tool holding cable secured with respect to the boat and causing the cable to move away from the vertical plane, a nonvertical track for the guidance and displacement of said single assembly means and thereby the joint displacement of the pulleys supporting the anchoring cable and the tool holding cable, and a drive means fixed to the deck of the boat exerting a force on said single assembly means and composed of at least one horizontal part so as to stretch said cables.

3. A device as claimed in claim 2, comprising in addition a general frame on which rests the displacement track of said assembly means.

6. A device as claimed in claim 2, in which the pulley assembly means comprises two parts mobile with respect to each other, the one supporting the anchoring cable second pulley and the other supporting the first pulley of the tool holding cable, said drive means exerting a stress at constant tension on the part of the assembly supporting the pulley of the anchoring cable, the other part of the assembly being disposed between said drive means and the part of the assembly supporting the second pulley of the anchoring cable.

8. A device as claimed in claim 6, in which said drive means is a jack.

9. A device as claimed in claim 2, in which the pulley assembly means comprises two side plates each supporting one end of the shaft of the support cable pulley, each of the ends of the shaft of the pulley resting in a suitable notch in the supporting side plate.

11. A device as claimed in claim 10, further including another fork, a trestle and a control lever, in which the assembly of the support arms of the forks and their control lever is mounted on a trestle displaceable along a path parallel to the path of the pulley assembly means, and a path securing means for maintaining said trestle in position when the shaft of the pulley supporting the tool holding cable is picked up by said forks.

17. An anti-pounding device as claimed in claim 16 in which the assembly means for carrying the pulleys comprises a carriage means having a plane of vertical symmetry, rollers with horizontal axes perpendicular to the plane of symmetry situated at its upper part on either side of the plane of symmetry, the lower rollers resting on a lower rolling path and the guide rollers cooperating with an upper guide path parallel to the first, these paths being situated in the plane of symmetry of the carriage means.

19. An anti-pounding device as claimed in claim 18, in which a boom and the anti-pounding device are supported by the central tower so as to be capable of rotating 360* about the axis of the tower, the boom and the anti-pounding device being supported by the tower independently of each other.

20. An anti-pounding device as claimed in claim 16, in which the pivot of the compensation bar is secured to the deck of the boat and in which the return pulleys disposed on the boom of the crane are swivelable.