US3730122A - Salvage pontoon - Google Patents

Abstract

A salvage pontoon characterized by flat suction coupling plates, object attaching arms having explosive driven studs, and a cryogenic gas supply is disclosed. A ballast arrangement is disclosed to permit raising of the object and attached pontoon in controlled increments.

Description

United States Patent 1191 Odum et a1.

[ 1 SALVAGE PONTOON [75] Inventors: William T. ()dum, Panama City; James H. Elkins, Lynn Haven;

Thomas M. Coggins, Panama City, all of Fla.

[73] Assignee: The United States of America as represented by the Secretary of the Navy [22] Filed: May 5, 1971 [211 App]. No.1 140,438

52 u.s.c1 ..ll4/53,l14/16.4 51 1m.c1 ..B6 3 c7/08 5s FieldofSearch ..114/50,51,53,52, 114/164, 16 E, 16 R; 61/69, 71; 9/8; 294/64 [56] References Cited UNITED STATES PATENTS Sellner et a1. ..1 14/16 E Primary Examiner-Milton Buchler Assistant Examiner-Gregory W. OConnor Azt0rneyRichard S. Sciascia, Don D. Doty and William T. Skeer ABSTRACT A salvage pontoon characterized by flat suction coupling'plates, object attaching arms having explosive driven studs, and a cryogenic gas supply is disclosed. A ballast arrangement is disclosed to permit raising of the object and attached pontoon in controlled increments.

9 Claims, 7 Drawing Figures Patented May 1, 1973 3,730,122

3 Sheets-Sheet 1 WILLIAM T. ODUM JAMES H. ELKINS THOMAS M. COGGINS INVENTORS BY Q ZQZM f 1% Ja /4A ATTORNEY INVENTORS f {11 A WILLIAM T. ODUM JAMES H ELKINS THOMAS M. COGGINS 3 Sheets-Shut 2 I! ////I F F A w:

Ev 6? .ON

Patented May 1, 1973 ATTORNEY Patented May 1, 1973 3 ShutbS'nuc 3 TO PONTOON l2 FIG.6

W'LLIAM T. ooum JAMES H. ELKINS THOMAS M. COGGINS INVENTORS BY ff M SALVAGEPONTOON STATEMENT OF GOVERNMENT INTEREST The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

CROSS REFERENCE TO RELATED APPLICATIONS This application discloses a variable buoyancy pontoon which is a component part of a deep sea salvage system. Other components of the system include a manned deep sea vehicle disclosed in US. Pat. application Ser. No. 132,032, filed Apr. 7, 1971, for Salvage Work Vehicle, by the applicants in this application, and an electrical connector disclosed in US Pat. No. 3,665,509, filed Mar. 22, 1971, for Underwater Electrical Connector by James H. Elkins.

FIELD OF THE INVENTION This invention pertains to the field of oceanographic engineering. More particularly, but not by way of limitation, the invention pertains to deep sea salvage. In still greater particularity, the invention pertains to a pontoon which may be used for deep sea salvage or in other oceanographic tasks where great weight must be lifted from the ocean depths, such as is sometimes required in certain oil well drilling operations on the ocean floor.

As nuclear power plants become more common and payloads of chemical products increase, the risk of ocean pollution by marine accidents grows greater. Of course, recent design changes in ships having these contents have reduced the danger to a great extent. Despite these changes in ship design, it becomes more urgent that a method and means be available to recover marine wrecks from the ocean floor to avoid massive ocean pollution therefrom. Quite naturally, the economic value of the salvage is also of considerable importance. It is also desirable to recover wreckage of vessels in which the cause of their sinking is unknown. The study of such wrecks is valuable in the design of new ships in order to prevent similar disasters from recurring.

DESCRIPTION OF THE PRIOR ART The most successful prior art system of recovery of massive loads from the ocean depths has employed surface lifting techniques. In such operations, a surface pontoon is positioned above the object to be lifted and a lifting cable is attached to the object to be recovered. The object is then raised to the surface by hauling the cable upwardly.

This operation requires great expenditures of time and money to position and operate the powerful winches. The system is also weather dependent since the success of the operation depends upon a calm sea. The load to be lifted, when attached to the cable, becomes a massive pendulum and great care must be taken to avoid attendant mechanical resonances. Such mechanical resonances could exceed the structural strength of the equipment causing the load to sink again. Such repeated sinkings not only damage the salvage equipment and cause expensive delays, but

often cause further damage to the salvage object risking pollution and economic loss. Loads of 110 tons have been raised in this fashion but are considered to be the limiting size for this type of salvage operation.

SUMMARY OF THE INVENTION This invention provides a submersible salvage pontoon which is maneuvered into direct contact with the object to be lifted by manned deep submergence vehicles. The pontoon is attached to the object to be lifted by the crew of the manned vehicle or by remote control from the surface. The attachment to the salvage objects is made by one of several different types of support arms described herein. When the pontoon is attached, it is made positively buoyant by release of suitable ballast carried therein and by displacing water therefrom by gas supplied by two large cryogenic dewars carried therein. The rate of ascension of the pontoon is controlled from the surface by a mechanism which releases, upon command, lengths of steel cable connecting the pontoon with the ballast.

When the pontoon, with its load attached, has reached a modest depth, lines are made fast to the load and connected to surface barges or pontoons and the salvage operation may continue from the modest depths in a conventional fashion.

Each pontoon of the invention is capable of lifting 300 tons from l50 fathoms, a heretofore unprecedented salvage capability.

With the foregoing description in mind, it is an object of this invention to provide an improved salvage pontoon.

It is a further object of this invention to provide an improved method and means to lift submerged objects from the depths of the ocean to the surface thereof.

It is another object of this invention to provide a salvage buoy with a self-contained variable buoyancy system.

It is another object of the invention to provide a salvage pontoon which may be attached to a variety of submerged loads by remote control.

Another object of this invention is to provide a salvage pontoon with a liquified gas supply therein.

A further object of the present invention is to provide a salvage pontoon with improved lift capabilities.

A still further object of this invention is to provide a salvage pontoon with interchangeable load attaching supports.

Another object of this invention is to provide a salvage pontoon having improved submergence and surfacing apparatus.

Yet another object of this invention is to provide a salvage pontoon which is designed to be positioned by deep submergence vehicles.

A further object of this invention is to provide a salvage pontoon with a ballast control system to permit the rate of emergence thereof to be controlled from the BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an elevation view of the pontoon of the invention in a hypothetical operational environment;

FIG. 2 is an end elevation view of the pontoon of the invention showing a tubular attachment arm and a flexible attachment means;

FIG. 3 is a side elevation view of the pontoon of the invention with the body portion thereof shown in partial section;

FIG. 4 is a diagrammatic showing of the restraining cable and ballast arrangement according to the invention;

FIG. 5 is a perspective view of the restraining cable attachment arrangement;

FIG. 6 is a sectional view of a plate type attachment arm taken along lines 66 of FIG. 3; and

FIG. 7 is a plan view of the mounting plate arrangement used on tubular type attachment arms.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. 1, a load, such as a sunken ship 11, to be raised is shown as resting on the sea bottom. A salvage pontoon 12 is attached thereto by suitable arms 13. A deep submergence salvage work vehicle 14 is attached to each end of pontoon 12 for positioning thereof relative to ship 12 prior to the attachment of arms 13 thereto. Deep submergence vehicle 14 has an external manipulator arm 15 which is used for attaching arms 13 to ship 11, for moving conductor 16, and other purposes. When pontoon 12 is positioned in cooperative relation to ship 11, deep submergence vehicle 14 may separate therefrom and maneuver independently.

An electrical conductor 16 is lowered from the sea surface and has a connector plug 17 secured to the distal end thereof. As will be understood by those familiar with salvage operations, plug 17 is grasped by arm 15 and inserted into a receptacle 18, which is mounted on pontoon 12. In instances where a plurality of pontoons 12 are required, a single conductor 16 may be lowered from the surface with a junction box, not shown, on the distal end thereof, in place of connector 17. Further conductors emanating from the junction box with connectors 17 thereon are placed in receptacles 18 on the individual ones of the plurality of pontoons 12.

Attachment of the deep submergence salvage work vehicle 14, hereafter termed salvage vehicle, to salvage pontoon 12 is accomplished by means of a suitable vacuum or hydrostatic coupler 19. Couplers l9 cooperate with flat portions, to be more completely described herein, on each end of salvage pontoon 12 in such a manner as to attach salvage vehicles 14 thereto. If desired, salvage vehicles 14 may be interconnected so that control thereof may be exercised from a single vehicle. This control interconnection may be accomplished by a fixed wire communication link within salvage pontoon 12, or, if desired, by an acoustic wave, i.e., sonar-like, communication link through the water. Both of these arrangements may be incorporated in each salvage vehicle, one serving as a back-up system for the other, if desired. The exact nature and functioning of the control system has no direct bearing to the present invention and, since prior art systems capable of providing the communication link are well known, the selection of a suitable system is left to the choice of the skilled worker making and using the invention.

Referring now to FIG. 2, an end elevation of pontoon 12, it may be seen that pontoon 12 comprises a box-like base portion 21 and a cylindrical tank-like buoyant portion 22. Suitable supports 23, spaced at predetermined intervals, join base portion 21 and buoyant portion 22. The number and location of supports 23 are, of course, depend upon the material from which they are made and the expected loads to be borne thereby. It should be noted that the illustrated configuration is but an exemplary construction and other arrangements are possible. For example, base portion 21 may extend upwards to join and partially enclose buoyancy portion 22 so as to incorporate supports 23 as integral portions thereof. These constructional details are well understood parameters of design to persons familiar with the fields of naval architecture and, quite naturally, may be varied to suit the individual circumstances of the particular requirements. For purposes of explanation, it need only be noted that the construction serves to rigidly unite the component parts of pontoon 12 into a rigid assembly capable of withstanding the loads placed thereon.

On suitable bulk heads, to be more completely described, located at each end of cylindrical buoyant portion 22, coupling plates 20 are located. Coupling plates 20 serve as attachment points for vacuum couplers 19 and may simply be flat steel plates, if desired. However, since the vacuum seal is the means by which pontoons 12 are moved by salvage vehicles 14, coupling plates 20 may be modified to promote cooperation with their mating parts. One type of modification includes a coating of the surface of coupling plate 20 with a plastic or synthetic rubber compound to promote a watertight seal therewith by gasket means on vacuum coupler 19. In place of coatings, or in addition thereto, the face of plate 20 may be figured to promote a watertight seal. Such figuring is well understood in the vacuum attaching and vacuum chuck arts. The selection as between coatings, figurings and combinations of the two is regarded as a matter of design choice.

Along the center of the upper surface of buoyant portion 22, where receptacle 18 is located, a plurality of suitable hatches 24 are installed. Hatches 24 permit crew members to enter the interior of the buoyant portion 21 for service thereof. Of course, in operation pontoon 14 is unmanned and the hatches are secured. Since entry into the buoyant portion 21 is infrequent, hatches 24 may be secured with threaded fasteners or other semi-permanent fastening means.

Receptacle 18 may be any multiconductor electrical connection means constructed for electrical connection in underwater environments. For example, the connector described in the aforementioned US. Pat.

No. 3,665,509 for Underwater Electrical Connector,

filed Mar. 22, 1971, by James H. Elkins, one of the inventors of the incident invention, was especially designed for this application. However, the successful operation of pontoon 12 does not depend on any particular electrical connector construction and, accordingly, no specific construction thereof is shown herein.

Buoyant portion 22 contains, in suitable interior compartment means, suitable, large-volume, cryogenic Dewar flask means 25. Suitable support means 26 provide secure mounting for Dewar flash means 25. A more complete explanation of this portion of the invention will be provided in connection with the description of FIG. 3, where the details of the cryogenic Dewars are more clearly shown.

Base portion 21 houses, along with other components, the ballast components of pontoon 12. A weighted hatch 26 has an eye bolt 27 extending therethrough. A suitable ballast chain 28 is secured to eye bolt 27 and disposed within a ballast compartment 30 within base portion 21. As will be more completely described presently, the ejection of hatch 26 along the direction shown by arrow 29 drags ballast chain 28 thereafter to cause the lightening of pontoon 14. Although a plurality of hatches 26 are provided, only one is shown as being deployed for purposes of illustration. In operation all are deployed simultaneously.

Ballast chain 28 is of any suitable construction to provide the necessary weight, so as to obtain the desired change of buoyancy when ejected. In a developmental embodiment of the invention standard anchor chain has proven satisfactory. The type of chain employed was twelve centimeter chain weighing 7,600 Kg per 25 meter shot. If heavier chain is required, it may be especially fashioned for this purpose and may comprise lead clad steel links, for example. Of course, if lesser weights are specified, other stock chains may be employed. The terminology ballast chain as used herein may refer to any suitable configuration of ballast weights and should not be construed as limited to the linked chain form disclosed herein. However, the restraining control means, to be described presently, limits the ballast to some unitary construction that may be made fast to a line or cable.

The attachment arms, shown generally at 13 in FIG. 1, are also carried by base portion 21. Attachment arms 13 are of two general types, rigid and flexible. Each type of arm is mounted on a pair of outwardly extending mounting bosses 31. A plurality of pairs of bosses 31 extend along each side of base portion 21 to permit the number of arms to be selected in accordance with the particular circumstances. For purposes of simplicity of illustration, arms are shown as being attached to only one side of base portion 21. In actuality, of course, both sides of base portion 21 have arms attached thereto.

Likewise, for purposes of explanation, two types of arms are shown in FIG. 2. It should be understood, in actual practice, only a single type of arm need be used. Some situations, however, may require the use of arms of different types, as illustrated.

One type of arm is formed of a belted chain 32. Belted chain 32 offers the advantage of conforming to a variety of different load shapes. Also, belted chain 32 permits fastening pontoon 14 to loads, such as ship 11, in such a fashion as to lift the load in a different orientation than it is found in. Thus, belted chains 32 may be attached to the port and starboard sides of the deck of a wreck lying on its side so as to lift it in an upright fashion.

FIG. 2 also illustrates a tubular arm 33 mounted on base portion 21. Although shown as straight, tubular arm 33 may be formed so as to fit and captively embrace irregular shapes such as specific hull shapes. At the outboard end of arm 33, a mounting plate 34 is hingedly attached so as to be movable to rest in surface contact with the object to be lifted at a suitable mounting point thereon. Mounting plate 34 will be more completely described herein.

Rather than depending vertically downwardly, as in the case of belted chain 32, tubular arm 33 may be held outwardly from pontoon 12 by suitable support means, such as a chain 35, extending between eyes 36 on the outer end of tubular arm 33 and on buoyancy portion 22. Provisions may also be provided, if desired, for adjusting the length of the support means and, thereby, the position of tubular arms 33. Such a length adjustment may be provided for chain 35 by a turnbuckle 37. Means, not shown, may also be provided to sever or otherwise part chain 35 to cause arms 33 to drop from their outwardly supported position to a downwardly extending position. This arm repositioning operation may be accomplished when salvage pontoon 14 is in the desired position with respect to the object to be lifted.

Referring now to FIG. 3, a side elevation of salvage pontoon 12 with a portion thereof broken away for illustration purposes. However, in place of tubular arms 33, plate arms 38 are shown mounted on either end of base portion 21 in bosses 31. As previously indicated, bosses 31 are of a standard spacing to accept a variety of attaching means to connect pontoon 14 to the load to be raised, such as ship 1 1. In this regard, the varieties of arms shown and described herein should be regarded as only exemplary embodiments. As the number of salvage pontoons 12 increase and they become more commonly available, it is envisioned ships plying the world waterways will carry arms or other fittings to be received and held by standard arms or attached directly to bosses 31.

It should also be apparent that bosses 31 themselves, are subject to modification. Of course, other attachment means may be installed on base portion 21 to receive the standard attachment arms. Accordingly, as experience is gained in the use of the pontoon of the invention, skilled workers may make desired modifications to the invention without departing from the scope thereof.

Buoyant portion 22 has a cylindrical hull portion 39 closed at each end with end bulkheads 41. As previously noted, coupling plates 20 are located on bulkheads 41. As shown, salvage pontoon 12 is symmetrical and both end bulkheads 41 are of the same shape. However, if desired, they could be configured to provide a more hydrodynamically shaped bow at one end to enhance surface towing of pontoon 12 so as to promote surface transport thereof to the site of the salvage as well as hasten the deployment thereof.

In either construction, symmetrical or unsymmetrical, bulkheads 41 cooperate with hull portion 39 to form a stressed enclosure for the cryogenic gas supplies and other components to be kept dry and at regulated pressures. Hull portion 39 is made of sheet steel with reinforcement provided by suitable ribs 42 spaced at predetermined intervals therealong. Ribs 42 are of 1 section steel although other structural shapes may be used, if desired.

Two interior bulkheads 44, one shown, divide the interior of buoyant portion into three compartments.

Aside from their portioning function, bulkheads 44 add compressional strength and torsional rigidity to the structure of buoyant portion 21. Bulkheads 44 are substantially the same as the exterior and bulkheads 41 with the obvious exception that they have no coupling plate installed thereon. Bulkheads 44 are spaced in such a predetermined fashion that the end compartments defined thereby are of smaller volume than the center compartment located therebetween.

A cryogenic Dewar is located in each of the end compartments. Although there are other components of the salvage pontoon system located therein, the size of Dewar 25 primarily determines the placement of bulkheads 44 and, therefore, the relative sizes of the compartments. Cryogenic Dewar 25 is held in place against the forces resulting from the movement of pontoon 12 by a suitable support means 45. Dewar 25 and its support means 45 are conventional state-of-the-art components which are well known in the cryogenic engineering arts. Since several types thereof are available, the choice between them is left to the proficient artisan.

Each Dewar 25 is of sufficient size to exhaust the central compartment of water. The two Dewars 25 have, therefore, the combined capacity to make two salvage lifts before requiring replenishment. Dewars of such large capacity require pressure regulation to perform at deep ocean depths. Pressure regulation is provided by suitable pressure regulators 46 which, like Dewar 25, is of conventional state-of-the-art construction. The boil-off gas is vented to the outside by regulator 46 by means of a conduit 47.

The center compartment of buoyant portion 22, located between bulkheads 44, comprises the variable buoyancy portion of pontoon 12. Water, which fills the compartment during periods of negative buoyancy and partially fills the compartment during periods of neutral or controlled buoyancy, is pressure equalized by means of a standpipe 48. As may be seen in FIG. 3, standpipe 48 communicates between the interior of the central compartment and the outside ambient water.

Standpipe 48 is of an inverted U shape having open ends. The interior opening thereof is near the deck, or lower surface, of the central compartment. The interior opening is in one end of standpipe 48. The other end thereof is somewhat longer and penetrates the cylindrical hull portion 39 to open on the exterior of buoyant portion 39. Standpipe 48 is mounted by means of triangular braces 49 which, in addition to their supporting function, brace standpipe against flexure caused by movement of water at high pressures therethrough.

The transfer of gas from Dewar 25 to the central compartment is initiated by response to an electrical command signal from the surface transmitted via electrical conductor 16, electrical connector 17 (FIG. 1) and receptacle 18. The internal wiring of pontoon 12 is not shown since it is not necessary for the understanding of the invention and since, even though complex and extensive, such wiring systems are well understood and within the skill of one versed in the marine engineering arts. The draining of the liquified gas from Dewar 25 is controlled by cryogenic control valve apparatus 51.

Rather than supply gas directly to the buoyancy compartment, valve 51 routes the gas, via conduit 52, to a heat exchanger 53. As will be well understood by those familiar with liquified gases, the change of state from a liquid to a gas is accompanied by a thermal exchange. If an attempt is made to effect the exchange directly there would be danger that the water surrounding the discharge end of the conduit would freeze to create a blockage thereat. Such blockage, coupled with the rapid rise of pressure, might result in explosive forces being generated within the system. The presence of heat exchanger 53 in the system lessens this possibility. Heat exchanger 53 is located within base portion 21 and is in thermal contact therewith and with the surrounding water. The gaseous output from heat exchanger 53 is transferred to the interior of buoyant portion 22 by means of conduit 54 connected therebetween. Of course, some thermal transfer occurs as the gas passes through conduits 52 and 54. The temperature of the gas is raised until it enters the central compartment, where its temperature is above the freezing point of sea water.

The gas entering buoyant portion 22 displaces the water therein through standpipe 48 in the well understood fashion common within the submarine engineering discipline. The ejection of the water therefrom and its replacement with gas from Dewar 25, of course, results in a change of buoyancy for pontoon 12.

Before pontoon 12 is attached to the object to be raised, its buoyancy is controlled to closely approximate neutral buoyancy by control valve 51. After pontoon 12 is attached, the ballast is jettisoned and valve 51 controls the buoyancy to provide positive buoyancy so as to raise the object to the surface. Control valve 51 is actuated from the surface, via the previously described control link, to accomplish the desired changes in degree of buoyancy regulation.

As previously described, ballast chain 28 is jettisoned by releasing hatch 26 to which it is attached by eye bolt 27. Hatch 26 is held in place in base portion 21 by means of latch bolts 55 which engage cooperating holes 56 in the margin thereof. Latch bolts 57 are explosively severed upon receipt of electrical .command signals from the surface, as obviously described. As the ballast chain 58 pays out, the buoyancy of pontoon 12 and its attached load alters to become positive so as to start to ascend.

As is well understood, an uncontrolled ascent is not desired. To provide a control for the rate at which pontoon 12 surfaces ballast chain 28 is connected to suitable restraining cable means 57, see FIG. 4, by suitable attaching tackle 58. Of course, restraining cable 57 is attached to base portion 21 of salvage pontoon l2 and is of sufficient length to reach the surface, or to the height from the bottom to which it is desired to lift the salvaged object. However, rather than being payed out continuously or at one time, restraining cable 57 is payed out in predetermined lengths so as to permit pontoon 12 and its attached load to be raised in controlled increments. To accomplish this end, said predetermined lengths of restraining cable 57 are wound into a plurality of loops 59. Each loop 59 is bridged by a short length of cable 61 with an explosive cutter 62 positioned in cooperative relation thereto.

Cable 61 provides strain isolation for its associated loop 59. Firing each cutter 62 severs short cable 61 and thereby permits the particular loop 59 associated therewith to be payed out.

Referring to FIG. 5, restraining cable 57 has the loops 59 placed inside a frangible tube 63. This constructional convenience permits the storage of a considerable number of loops 59 without entanglement. Loops 59 are adhesively secured to the inner surface and explosive cutters 62 are positioned along the outer surface and extend the walls of tube 63. The buoyancy force of pontoon l2 extracts cable 57 pulling it free of tube 63. Tube 63 may break away as cable 57 is withdrawn therefrom. Instead of a single tube with circular coils 59, a double tube arrangement with figureeight shaped coils, not shown, may be used, if desired. Such an alternate arrangement requires a smaller tube length for a given length of restraining cable 57. Tubes 63 are located within base portion 21 and cutters 62 are electrically fired in sequence on command from the surface.

Referring to FIG. 6, a sectional view of plate arm 38 taken along line 6-6 of FIG. 3, one will see that the structure is built on a T section beam 64. A plurality of threaded holes in the flange, or base plate portion, of beam 64 accept explosive driven stud assemblies 65 therein. Explosive driven stud assemblies 65 are conventional state-of-the-art units. Stud assemblies 65 are fired electrically from the surface via the aforedescribed command link. Conductors 66 on arm 38 complete the circuit to the individual stud assemblies. Gaskets 67 are located along the object engaging surface of arm 38 form watertight contact with the object to be lifted when arm 38 is resting thereon. Gaskets 67 together with arm 38 form a vacuum gripping surface with the object to be lifted in the same manner as vehicle 14 attaches pontoon 12 thereto. A source of vacuum connected thereto by conduit means, not shown, causes arm 38 to be drawn into contact with the object to be lifted. This contact enhances the penetration and effectiveness of explosive driven studs 65.

Referring to FIG. 7, the distal end of tubular arm 33, as illustrated in FIG. 2, is shown. As may be seen, mounting plate 34 is attached to arm 33 by means of a hinge 68. Like plate arm 38, previously described, mounting plate 34 has a plurality of explosive driven studs 65 mounted thereon. To increase the area of attachment ears 69 may extend outwardly from plate 34 with studs 65 mounted thereon.

Chain belt arms 32 may also carry mounting plates 31 at the distal ends thereof.

MODE OF OPERATION Having described the construction ofa preferred embodiment of the invention, the manner of employment of the device to accomplish the objects of invention will now be set forth.

Salvage pontoon 12 is first transported to the salvage cite. This may be accomplished either with surface towing techniques or as deck cargo on a suitable salvage vessel or barge. When at the salvage cite and in the water, salvage work vehicles 14 take salvage pontoon 12 in tow and transport it to the wreck, or other object, to be raised thereby. Attachment of work vehicle 14 to pontoon 12 is made by a vacuum coupler attached to coupling plate 26. During this transportation time, valve mechanism 51 regulates the buoyancy of pontoon 12 to assure that it is neutrally buoyant.

When pontoon 12 is in place with respect to the wreck, work vehicle 14 detaches itself therefrom and positions the lifting arms in place with respect to the wreck. The precise operations performed depend in large measure on the particular type of arm that is fitted on salvage pontoon 12.

If the belted chain arms 32 are fitted, the crew in salvage work vehicle 14 move the end thereof into cooperative arrangement with ship 11, or other object to be raised. In some instances, salvage pontoon 12 may be placed alongside ship 11 and connections of belted chain arms made thereto in such a manner that ship 11 is raised in a different attitude than it occupies on the bottom. The particular manipulative steps depend upon the precise nature of the fastenings on chain belt arms 33. If mechanical fittings are employed, the connections are made by the use of manipulator 15. If explosive driven studs are employed, the crew of work vehicle 14 place the terminating pad on which studs 65 are mounted in the desired position to which attachment is to be made. This mounting pad, not illustrated in the drawings, may be the same as mounting plate 34 used on tubular arm 33.

If the inflexible tubular arms 33 are used on salvage pontoon 12, the degree of manipulation by the crew of work vehicle is correspondingly less. In such instances, the work vehicle crew releases arms 33 from the supporting chains 35 to cause them to come to rest on ship 11. Plates 34 are hinged into operating position by use of manipulator 15 when tubular arms 33 are in place.

A similar positioning procedure is employed if plate arms 38 are mounted on salvage pontoon 12. When arms 38 are equipped with the vacuum attachment means, the crew of work vehicle 14 make the necessary vacuum connections thereto to draw arms 38 tightly into contact with ship 11 prior to the detonation of explosive driven studs 65.

As previously noted, the rigid type arms may be shaped to conform to the desired object shape which is to be raised to the surface. For example, if a small diameter submarine vehicle is to be raised the arms may be formed to encircle the load. If, however, the object to be raised is of a large diameter the arms may be curved to conform to the surface so as to thereby promote contact therewith without encircling the load. The linear arms used as exemplary constructions herein may be regarded as being shaped to conform to barges or the flat plate sections of large ocean going ships.

When pontoon 12 is in place and attached to ship 1 1, electrical conductor 16 is lowered from the surface and connector 17, attached thereto, is placed in receptacle 18. In instances where plural pontoons 12 are placed on ship 11, conductor 16 may terminate in a junction box and a plurality of short cables each with a connector 17 on the end of each thereof. When plug 17 is in receptacle 18, command of salvage pontoon 12 is exercised from the surface.

When the particular arms in use are in position and the command link to the surface is established, explosive studs 65 are fired to firmly attach pontoon 12 to ship 11. Ballast is then jettisoned by detonating latch bolts 55 which cause hatches 26 to be expelled dragging ballast chain 28 therebehind. Work vehicles 14 may assist in this operation to assure that hatches 26 and the ballast chain attached thereto are free of ship 11 as well as pontoon 12. In some embodiments it may be desirable to route ballast chains 28 through tubular arms 33 with hatches 26 at the outboard ends thereof.

When pontoon 12 is unburdened of ballast, valve 51 regulates the buoyancy of pontoon l2 and attached ship 11 to be positive. Having positive buoyancy, pontoon l2 rises to the level permitted by restraining cable 57. Ship 11, being attached thereto, rises with pontoon 12. When at the height permitted by restraining cable 57 valve 51 readjusts the buoyancy of pontoon 12. If

plural pontoons are used, the trim or attitude of the ship 11 and pontoon 12 combination is adjusted at this time by regulating the relative buoyancy of the several pontoons 11. I

When pontoon l2 and ship 11 have been stabilized in the desired attitude, an explosive cutter 61 is detonated to release a loop 59 of restraining cable 57 to allow pontoon 12 together with ship 11 to rise another predetermined increment. This process is repeated until pontoon 12 has raised ship 11 to the surface or other desired working level.

Obviously, other embodiments and modifications of the subject invention will readily come to the mind of one skilled in the art having the benefit of the teachings presented in i the foregoing description and the drawings. It is, therefore, to be understood that this invention is not to be limited thereto and that said modifications and embodiments are intended to be included within the scope of the appended claims.

What is claimed is:

l. A salvage pontoon for use in recovering a large object from a great ocean depth comprising in combination:

buoyant chamber means for providing regulatable buoyancy for said pontoon;

base portion means attached to said buoyant chamber means for providing mutual support therebetween;

object engaging arm means attached to said base portion means and depending therefrom for attaching an object to be recovered thereto; plate means disposed at predetermined positions on said buoyant chamber means for facilitating the attachment of vacuum coupler means thereto, so as to effect the towing of said pontoon thereby;

ballast chamber means, having an opening therein, located within the interior of said base portion means for containing ballast means therewithin;

weighted hatch means fitting the opening of said ballast chamber means and releasably secured to said base portion means for providing closure means for said ballast chamber means;

ballast chain means stored within said ballast chamber means and secured to said weighted hatch means in such manner as to be jettisoned from said ballast chamber means when said weighted hatch means is released from said base portion means; and

restraining means connected between said ballast chain means and said base portion means for limiting the movement of said pontoon in response to the jettisoning of said ballast chain means.

2. A salvage pontoon according to claim 1 in which said buoyant chamber means further comprises:

bulkhead means located within said buoyant chamber means and attached thereto for the separation thereof into a plurality of watertight compartments;

gas supply means located in at least one of said watertight compartments for providing buoyant gas for said pontoon means;

standpipe means located in another of said watertight compartments for transfer of water therethrough in such a manner as to flood or exhaust said buoyant chamber means; and

means connected between said gas supply means and said standpipe equipped water tight compartment for the selective transfer of gas therethrough in such a manner as to effect the expulsion or admission of water, so as to alter the buoyancy of said pontoon.

3. A salvage pontoon according to claim 2 in which said gas supply means comprises a cryogenic Dewar for containing therein gas in a liquid state.

4. A salvage pontoon according to claim 2 in which said standpipe means comprises an open fluid conduit having an inverted U shape, with one end thereof in fluid communication with the exterior of said buoyant chamber means, and with the other end thereof in close proximity with the lower interior surface of watertight compartment.

5. A salvage pontoon according to claim 2 in which means connected between said gas supply means and said standpipe equipped watertight compartment comprises a heat exchanger in thermal contact with the ambient environment for transfer of the heat of vaporization of the liquified gas passing therethrough thereto.

6. A salvage pontoon according to claim 1 in which said restraining means further comprises:

cable means attached to said ballast chain means at one end thereof and to the aforesaid base portion means at the other end thereof and wound into a plurality of loops of predetermined lengths for providing a flexible tether between said anchor chain and said salvage pontoon;

cable sections extending across each of said loops to provide strain isolation therefor; and

remotely actuated cutter means disposed in cutting relation to said cable sections for the selective severing thereof, so as to cause the coil isolated thereby to unwind.

7. A salvage pontoon according to claim 1 in which said object engaging arm means further comprise in combination:

an elongated member attached to said base portion means in such manner as to extend a predetermined distance therefrom;

mounting plate means effectively attached to said elongated member for surface contact with the object to be recovered; and

explosive stud means mounted on said mounting plate means and positioned so as to drive studs in said object for fastening said plate thereto in such a manner as to effect a unitary structural connection therebetween.

8. A salvage pontoon according to claim 7 in which said elongated member comprises a flexible belted chain means.

Claims (9)

1. A salvage pontoon for use in recovering a large object from a great ocean depth comprising in combination: buoyant chamber means for providing regulatable buoyancy for said pontoon; base portion means attached to said buoyant chamber means for providing mutual support therebetween; object engaging arm means attached to said base portion means and depending therefrom for attaching an object to be recovered thereto; plate means disposed at predetermined positions on said buoyant chamber means for facilitating the attachment of vacuum coupler means theretO, so as to effect the towing of said pontoon thereby; ballast chamber means, having an opening therein, located within the interior of said base portion means for containing ballast means therewithin; weighted hatch means fitting the opening of said ballast chamber means and releasably secured to said base portion means for providing closure means for said ballast chamber means; ballast chain means stored within said ballast chamber means and secured to said weighted hatch means in such manner as to be jettisoned from said ballast chamber means when said weighted hatch means is released from said base portion means; and restraining means connected between said ballast chain means and said base portion means for limiting the movement of said pontoon in response to the jettisoning of said ballast chain means.

2. A salvage pontoon according to claim 1 in which said buoyant chamber means further comprises: bulkhead means located within said buoyant chamber means and attached thereto for the separation thereof into a plurality of watertight compartments; gas supply means located in at least one of said watertight compartments for providing buoyant gas for said pontoon means; standpipe means located in another of said watertight compartments for transfer of water therethrough in such a manner as to flood or exhaust said buoyant chamber means; and means connected between said gas supply means and said standpipe equipped water tight compartment for the selective transfer of gas therethrough in such a manner as to effect the expulsion or admission of water, so as to alter the buoyancy of said pontoon.

3. A salvage pontoon according to claim 2 in which said gas supply means comprises a cryogenic Dewar for containing therein gas in a liquid state.

4. A salvage pontoon according to claim 2 in which said standpipe means comprises an open fluid conduit having an inverted ''''U'''' shape, with one end thereof in fluid communication with the exterior of said buoyant chamber means, and with the other end thereof in close proximity with the lower interior surface of watertight compartment.

5. A salvage pontoon according to claim 2 in which means connected between said gas supply means and said standpipe equipped watertight compartment comprises a heat exchanger in thermal contact with the ambient environment for transfer of the heat of vaporization of the liquified gas passing therethrough thereto.

6. A salvage pontoon according to claim 1 in which said restraining means further comprises: cable means attached to said ballast chain means at one end thereof and to the aforesaid base portion means at the other end thereof and wound into a plurality of loops of predetermined lengths for providing a flexible tether between said anchor chain and said salvage pontoon; cable sections extending across each of said loops to provide strain isolation therefor; and remotely actuated cutter means disposed in cutting relation to said cable sections for the selective severing thereof, so as to cause the coil isolated thereby to unwind.

7. A salvage pontoon according to claim 1 in which said object engaging arm means further comprise in combination: an elongated member attached to said base portion means in such manner as to extend a predetermined distance therefrom; mounting plate means effectively attached to said elongated member for surface contact with the object to be recovered; and explosive stud means mounted on said mounting plate means and positioned so as to drive studs in said object for fastening said plate thereto in such a manner as to effect a unitary structural connection therebetween.

8. A salvage pontoon according to claim 7 in which said elongated member comprises a flexible belted chain means.

9. A salvage pontoon according to claim 7 in which said elongated member is a rigid structural member having a predetermined configuration which conforms in a complementary manner with the shape of The object to be raised.

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