US3845893A

US3845893A - Methods for cutting and raising submerged masses

Info

Publication number: US3845893A
Application number: US00349748A
Authority: US
Inventors: M Banjavich
Original assignee: Taylor Diving and Salvage Co Inc
Current assignee: Taylor Diving and Salvage Co Inc
Priority date: 1973-04-10
Filing date: 1973-04-10
Publication date: 1974-11-05
Anticipated expiration: 1991-11-05

Abstract

A submerged mass is cut by repeatedly dropping a chopping tool thereon. The chopping tool is coupled to a hoisting mechanism carried by a floating platform and comprises a pair of flanges which have downwardly converging edges forming a pair of spaced cutting tips. A web extends transversely between, and is connected to, the flanges adjacent the cutting tips. The lower edge of the web is recessed to define with the cutting tips a pair of spaced impact points. The bottom edges of the tool are of bulbous configuration. A retrieval hook is dropped onto a section severed by the tool. The retrieval hook includes a pointed body portion and a grapple arm pivotally mounted to the body portion. The grapple arm is operable to swing outwardly of the body portion in response to penetration of the submerged mass by the pointed body portion. Subsequent lifting of the retrieval element causes the grapple arm to contact and lift the severed section.

Description

llnited States Patent 1 Banjavich METHODS FOR CUTTING AND RAISING SUBMERGED MASSES Inventor: Mark P. Banjavich, New Orleans,

Taylor Diving & Salvage Co., Inc., Bell Chasse, Plaquemines Parish, La.

Filed: Apr. 10, 1973 Appl. No.: 349,748

Assignee:

US. Cl. 225/1, 241/273 Int. Cl B26f 3/00 Field of Search 225/103, 1; 241/273;

5/1894 Kennedy.... 2/1929 Vialetal.

Primary ExaminerAndrew R. Juhasz Assistant ExaminerLeon Gilden Attorney, Agent, or Firm-Burns, Doane, Swecker & Mathis [57] ABSTRACT A submerged mass is cut by repeatedly dropping a chopping tool thereon. The chopping tool is coupled to a hoisting mechanism carried by a floating platform and comprises a pair of flanges which have downwardly converging edges forming a pair of spaced cutting tips. A web extends transversely between, and is connected to, the flanges adjacent the cutting tips. The lower edge of the web is recessed to define with the cutting tips a pair of spaced impact points. The bottom edges of the tool are of bulbous configuration. A retrieval hook is dropped onto a section severed by the tool. The retrieval hook includes a pointed body portion and a grapple arm pivotally mounted to the body portion. The grapple arm is operable to swing outwardly of the body portion in response to penetration of the submerged mass by the pointed body portion. Subsequent lifting of the retrieval element causes the grapple arm to contact and lift the severed section.

8 Claims, 10 Drawing Figures METHODS FOR CUTTING AND RAISING SUBMERGED MASSES BACKGROUND AND OBJECTS OF THE INVENTION This invention relates to the cutting of submerged masses and, more particularly, concerns methods and apparatus for cutting and removing submerged metallic structures, such as sunken vessels.

Considering the extent to which most countries are dependant in some way upon marine commerce and/or various other off-shore activities, such as pipeline laying and off-shore oil drilling, the importance of maintaining freely navigable waterways is readily apparent. The presence of sunken vessels or other debris, which may restrict or prevent the free passage of marine vessels, can produce considerable inconvenience and economic harm.

Even when not obstructing marine travel, such debris can be detrimental to the natural state of the environment.

As marine activity intensifies, the occurrance of collisions and other off-shore mishaps are likely to increase, resulting in the presence of yet greater quantities of vessel-restricting wreckage. Thus, the need for effective, economic and rapid techniques for the removal of sunken wreckage will become progressively more critical.

Unfortunately, sunken structures are often too large to be conveniently raised or lifted from the waterin one piece. lt is possible for a group of divers, armed with underwater torches and other implements, to cut the submerged structure into a number of individually raisable sections. In terms of the considerable time and expense involved, however, such an operation is of limited utility at best.

It is, therefore, a general object of the present invention to minimize or obviate problems of the types previously discussed.

lt is a further object of the invention to provide novel methods and apparatus for cutting a mass which is at least partially submerged.

It is a further object of the invention to provide novel methods and apparatus for cutting submerged masses, which methods and apparatus can be utilized substantially independently of divers.

It is another object of the invention to provide such novel methods and apparatus which utilize the effects of gravity in producing cutting forces.

It is another object of the invention to provide novel methods and apparatus for facilitating the cutting and- /l' removal of submerged objects, such as metallic structures for example.

Still another object of the invention is to provide methods and apparatus for retrieving remote objects, such as submerged structures, by a self-actuating element.

BRIEF SUMMARY OF A PREFERRED EMBODIMENT At least some of the foregoing objects are intended to be accomplished by the provision of a chopping tool cutting tips. A web extends transversely between and adjoins the flanges adjacent the cutting tips thereof. The lower edge of the web is upwardly concave to define with the cutting tips a pair of spaced impact points. The conversion edges on the concave edge include overlay material defining a bulbous configuration at the bottom of the chopping tool.

In operation, the chopping tool is floated above the mass on a floating platform. The chopping tool is suspended over the mass by means of a hoisting mechanism carried by the floating platform. The tool is then released for movement toward the mass such that the tool impacts and cuts the mass. The hole which is cut in the mass by the lower bulbous edges of the tool provides a clearance for the main body portion of the tool.

These steps are repeated, while shifting the chopping tool horizontally between successive cuts, until the mass is in a desired cut condition.

A visual guide can be provided for the operator of the tool by stringing a guide cable above the water surface in a direction generally parallel to a desired line of cut.

in deep water operations, the chopping tool may be confined within a guide frame which extends downwardly into the water. In this fashion, deflection of the chopping tool from its desired course of travel due to the effects of underwater currents and the like will be resisted.

In order to isolate the hoisting mechanism from undesirable vibrational effects caused by repeated impacts of the tool with an underwater mass, a shock absorbing assembly is disposed between the chopping tool and the hoisting mechanism. Preferably, this shock absorbing assembly comprises a plurality of vehicular or aircraft tires connected in series.

During operations involving the removal of a sunken In operation, the retrieval element is dropped onto a severed hull section such that the pointed body portion penetrates the outer plating of the hull. The body portion will penetrate the outer plating and will be abruptly halted when the abutment plate engages the outer plating. As a result, the grapple arm will swing outwardly to its extended position under its own weight. By subsequently lifting the retrieval element, the grapple arm will be brought into contact with the underside of the outer plating. Further lifting of the retrieval element will result in the severed hull section being lifted from the water bed. v

Once removed from the water, the severed hull sectionis placed on a suitable deposit station/The retrieval element is conveniently removed from the deposited hull section by removing the pivot pin of the grapple arm and detaching the grapple arm from the body portion.

THE DRAWING Other objects and advantages of the present invention will become apparent from the subsequent detailed description thereof in connection with the accompanying drawings in which like numerals designate like elements, and in which:

FIG. 1 is a schematic illustration of a chopping tool suspended over a submerged structure, according to the present invention.

FIG. 2 is a side elevational view of the bottom portion of the chopping tool impacting against a submerged structure.

FIG. 3 is a cross-sectional view taken along line 3-3 of FIG. 2.

FIG. 4 is a longitudinal sectional view taken along line 4-4 of FIG. 2.

FIG. 5 is a schematic illustration depicting two embodiments of the chopping tool being suspended over submerged structures.

FIG. 6 is a schematic illustration, in perspective, of a chopping tool disposed above a submerged hull and adjacent a guide cable according to the invention.

FIG. 7 is a side elevational illustration of a chopping tool confined within a guide frame, in accordance with the invention.

FIG. 8 is a plan view of a platform floatingly disposed over a submerged hull.

FIG. 9 is a side elevational illustration of a retrieval hook element according to the invention.

FIG. 10 is an illustration, in perspective, ofa severed section of a submerged hull being raised by the retrieval element.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS With reference to FIGS. 1 through 10 of the accompanying drawing, preferred method and apparatus aspects of the invention will be described in conjunction with the cutting and removal of vessels or hulls which are submerged in a body of water.

In accordance with the invention, the hull 10, shown in FIG. 1 as being submerged, is to be cut into individually raisable sections. This is accomplished by the utilization of a chopping tool 20, a preferred form of which is illustrated in FIGS. 1 through 4.

The chopping tool is carried by a suitable hoisting mechanism, such as a crane 21 having a boom 21b. The hoisting mechanism is disposed above the hull being cut. For example, the hoisting mechanism may be mounted on a floating platform 23.

The chopping tool 20 is generally vertically elongated and I-shaped in cross-section (FIG. 3). This tool 20 comprises a pair of flange plates 22 and an interconnecting web plate 24. The flange plates extend generally parallel and each flange includes side surfaces 25 and end edges 26. The lower portions of the end edges 26 converge downwardly such that the flanges define a pair of spaced cutting tips 30 (FIG. 4).

An overlay 32, preferably comprising a highly ductile material, such as nickel for example, as opposed to a brittle material, is provided along the bottom edge of each flange 22. The sides of this overlay material converge downwardly from the side surfaces 25 of the associated flange (see FIG. 2) to define a generally pointed cutting edge 34. Thus, in the preferred embodiment of the invention, the bottom edge of each flange 22, as defined by the overlay 32, is configured as a pointed, generally V-shaped cutting edge 34 (FIG. 4).

It will be apparent that the cutting tips 30 and the recessed web 24 define a pair of spaced impact points 42 separated by the recessed cutting edge 40. Thus, upon being dropped or propelled onto a submerged mass, the impact forces of the chopping tool will be concentrated at these two points. In this fashion, penetration of the mass at one or both of the impact points will be facilitated. Continued downward movement ofthe chopping tool through the submerged mass will enable the recessed edge 34 to progressively cut through that portion of the mass between the impact points. It will be understood that the curved recessed edge aids in cutting curved or angular surfaces, such as shafts.

The I-shaped structure of the chopping tool, wherein a pair of flanges 22 are interconnected by a perpendicular web 24, provides an arrangement wherein the flange and web elements reenforce one another to prevent twisting or bending of the tool.

Significantly, the

overlay portions

32 and 36 form bulbous, or enlarged edges at the bottom of the chopping tool 20 (See FIG. 3). That is, the bottom end edges of the chopping tool are enlarged relative to the main tool body thereabove. Such a bulbous configuration facilitates the penetration and removal of the chopping tool from a mass being cut. For example, and as viewed in FIG. 4, when the chopping tool 20 is dropped upon and penetrates a submerged steel structure 44, a hole 46 is cut in the structure. Since the bottom edges of the tool are bulbous, the hole 46 will be significantly larger than the main body portion of the chopping tool. The resultant clearance which is provided between the tool and the severed edges of the structure allows the flanges 22 and the web 24 to pass through the hole without being significantly resisted by frictional contact with the severed edges.

Bladed chopping tools which may be constructed in accordance with the teachings of this invention can vary in configuration depending upon the types of submerged masses to be cut. For example, and as shown in FIG. 5, a relatively wide chopping blade 50 is employed to cut a submerged structure 52 having a relatively thin frame and few decks. On the other hand, a relatively long and heavier chopping blade 56 would be employed to cut a structure 58 having a thick frame and many decks.

In the latter case, it will be apparent that hulls having several decks require a longer cutting blade and greater downward momentum to insure complete penetration. In order to produce sufficient momentum, the chopping tool 56 is heavier than the tool 50 and is suspended above the wreck 58 by a greater distance than that required of the smaller tool 50.

When a sunken vessel is to be cut into sections, it is desirable that the vessel be cut along its transverse and longitudinal bulkheads. FIG. 6 depicts a sunken hull 60 having a transverse bulkhead 64. An imaginary reference line 62 is shown in phantom along the outer plating of the submerged vessel. This line 62 corresponds to the location of the bulkhead 64. Since it may be necessary to drop the chopping tool in a number of repeated chopping steps, it might be difficult for the operator of the hoisting mechanism to observe the submerged vessel to properly re-position the tool 20 for successive drops.

In accordance with the invention, a visual reference, corresponding to the reference line 62, is provided. Such a visual reference may be defined by a guide line, such as a cable 66, which is strung between a pair of sunken pilings 68. The guide cable 66 is disposed above the water surface and is oriented parallel to the reference line 62.

Thus, during repeated droppings of the chopping tool, an operator will be afforded a visual reference guide afforded by the cable 66 for properly re-locating the tool 62.

The chopping tool may be moved horizontally after successive cutting steps in any suitable manner, as by shifting the crane 21, or by reeling and unreeling conventional mooring cables 74 by means of mechanical winches 72 to alter the position of the platform 23 (FIG. 8). It may also be possible to align the crane 21 relative to the cutting line 62 such that the chopping tool may be shifted by merely pivoting the boom 21b.

During such horizontal shifting of the cutting tool 20, the tool is preferably shifted so as to overlap approximately one-half its width with each successive cut.

it may be desirable, especially in deep water operations, to position the chopping tool within a vertically disposed guide frame 76 as illustrated in FlG. 7. If a crane 21 is employed, the guide frame 76 may be connected at the end of the boom 21b and supported by suitable bracing structure 77. The guide frame 70 confines the chopping tool during its downward motion and resists the effects of underwater currents and the like which might otherwise tend to deflect the tool.

In order to isolate the hoisting mechanism from the vibrational effects of the chopping tool, the present invention features the provision of a shock absorbing assembly 78. As may be seen in FIG. 1, the shock absorbing assembly 78 is in the form of a plurality of resilient elements 79, preferably conventional vehicular or aircraft tires, connected in series. Tires such as these are relatively inexpensive and easily obtainable. The tires may be interconnected in series by means of cables 81,

with the lowermost cable being suitably coupled to the chopping tool.

Once a section 69 of the hull 60 has been disjoined, or severed, it may be suitably retrieved. In accordance with this invention, a novel retrieval hook element 80 is utilized (FIG. 9). This retrieval hook 80 includes a pointed body portion 82 having an abutment plate 84 attached to its upper end. A grapple arm 83 is pivotally mounted within a pocket 86 of the pointed portion 82 by means of a removable pivot pin 88. This arm 83 is pivotal between a folded position wherein it is nested within the pocket 86, and an extended position wherein a stop shoulder 90 on the arm 83 abuts a limit surface 92 of the pocket 86, as shown in FIG. 9.

The retrieval hook 80 is arranged such that, upon being dropped downwardly onto a submerged hull for example, with the arm 83 in a folded position, the pointed portion 82 penetrates the outer hull plating 93. When travel of the hook 80 is abruptly halted, such as by contact of the abutment plate 80 with the outer plating 93, the arm 83 will swing outwardly, under its own weight, to an extended position below the outer plating. Subsequent lifting of the retrieval hook by a hoisting cable 90, attached to an eyelet portion 92 of the hook element, causes the grapple arm 83 to be raised into contact with the underside of the outer plating. In this manner, a firm coupling between the retrieval hook 80 and the severed section of the wreck will be effected.

When the severed hull section 69 has been lifted from the water and transferred to a suitable deposit station, the pivot pin 88 is removed from the hook. ln this fashion, the grapple arm 83 can be detached to enable the hook 80 to be freed from the hull.

OPERATION When it is desired to cut and remove a submerged structure, such as the sunken hull 60, a chopping tool 20 is suspended above the wreck. This may be accomplished by mounting the chopping tool on the crane 21, floating the crane upon the platform 23, and suspending the tool 20 over the side of the platform.

Depending upon the size and configuration of the sunken hull to be cut, an appropriate type of chopping tool 20 is selected. Thus, for a relatively large hull 58 having numerous decks, as shown in FIG. 5, the long, heavy, narrow chopping blade 56 will be employed. On the other hand, a shorter, wider and lighter chopping blade will be utilized for smaller hulls 52.

As noted previously, it is desirable to disjoin the hall along the bulkheads thereof.'To enable an operator to maneuver the tool along a path corresponding to the location of the bulkhead, a guide cable arrangement may be deployed. Thus, a pair of pilings 68 are driven, or otherwise placed, into the water bed. A cable 66 is then strung thereacross so as to be disposed above the water surface and in generally parallel alignment with the imaginary reference line 62 corresponding to the location of the transverse bulkhead 61.

- The chopping tool 20 is thereupon suspended over the side of the platform 23'adjacent to, but spaced from, the guide cable 66. At this point, the tool is released for movement toward the hull 60. This is preferably accomplished by merely letting-loose the hoisting cable carrying the tool such that the tool falls by gravity toward the hull.

Up to this point, the platform 23 has been anchored in place by the mooring cables 74. To reposition the chopping tool 20 for a subsequent chopping step, the

' platform 23 may be horizontally shifted by appropriate actuation of the winches 72. Alternatively, the tool may be shifted by relocating the crane 21 relative to the platform 23. Still further, if the crane 21 is aligned parallel to the reference line 62, the chopping tool may be properly shifted by pivoting the boom 21b.

During horizontal shifting movement of the chopping tool 20, the operator is able to maintain the chopping tool in proper alignment relative to the reference line 62 by observing the visual guide cable 66 and positioning the tool accordingly.

It is noted that in deep water operations it may be advantageous to locate the tool 20 within the guide frame 76 (FIG. 7) to assure that the tool is not unduly deflected from its desired downward path of travel by underwater currents.

After the chopping tool has been shifted by an appropriate amount, preferably by one-half of its width, it is subjected to a subsequent chopping drop.

This operation is repeated until an independently raisable section of the hull has been severed.

When it is desired to remove the severed section 69 of the hull from the water, a retrieval operation may be initiated, preferably by the retrieval hook element 80. Accordingly, the retrieval hook, connected at the end of a hoisting cable 90, is dropped downwardly upon the severed section 69, with the grapple arm 83 in a folded posture. When the knife portion 82 of the retrieval hook penetrates the outer plating 93 of the severed section and is abruptly halted, as by engagement of the abutment plate 84 with this outer plating, the grapple arm 83 will swing outwardly about its pivot pin 88 under the influence of its own weight.

Subseqnent lifting of the retrieval hook 80 will bring the grapple arm 83 into contact with the underside of the outer plating. Further lifting of the retrieval hook will raise the severed section from the water bed. As is depicted in FIG. 10, mud and the like which may have accumulated within the hull, will be free to flow outwardly from the severed section 69 as it is being raised.

While the chopping tool has been described herein in conjunction with the cutting of a submerged hull, it will be apparent that the tool may be employed to cut almost any type of structure or debris. Moreover, the tool may be utilized to cut into other masses, such as a water-bed in mining or dredging operations and the like.

It should also be apparent that the retrieval hook 80 is suitable for grasping and lifting any penetrable structure which will accomodate outward swinging of the grapple arm 83.

MAJOR ADVANTAGES AND SCOPE OF THE INVENTION The concept of cutting a submerged mass by repeated blows from a downwardly directed chopping tool affords a simplified, yet effective, cutting operation which utilizes gravity for producing the necessary cutting forces.

These forces will be effectively concentrated at one or two points on the mass being cut, due to the novel configuration of the cutting tool which is characterized by a pair of spaced impact points separated by a recessed cutting edge.

The lower edges of the cutting tool, being bulbous in shape, are able to cut a hole in the mass which is larger than the main tool body. As a result, there will be minimum frictional resistance exerted upon the tool in passing through the mass.

The generally l-shaped configuration ofthe chopping tool exhibits significant strength to effectively resist bending or twisting of the tool.

The employment of a guide line arrangement above the mass being cut affords a simple, yet effective means of providing a visual guide for an operator.

An effective manner of resisting deflection of the cutting tool is provided by the guide frame structure which 6 confines the chopping tool to substantially vertical travel through the water.

Vibrational shock which results from the tool striking the mass being cut is substantially isolated from the hoisting mechanism by the simplified, yet effective,

shock absorbing assembly 78.

5 The retrieval hook 80 of the invention is ofsimplified construction and is essentially self-actuating. Moreover, the hook is capable of convenient disassemblage to facilitate removal of the hook from a structure being retrieved.

Although the invention has been described in connection with a preferred embodiment thereof, it will be appreciated by those skilled in the art that additions. modifications, substitutions and deletions not specifically described may be made without departing from the spirit and scope of the invention as defined in the appended claims.

What is claimed is:

1. A method for cutting a mass which is submerged within a body of water, said method comprising the steps of:

positioning a chopping tool over said submerged mass;

releasing the chopping tool for downward movement toward said mass;

impacting said chopping tool against said mass to penetrate and cut said mass;

raising said tool by means of a hoisting mechanism connected to said tool; and

repeating said steps of positioning, releasing, impacting, and raising until the mass is in a desired cut condition.

2. A method for cutting a mass which is submerged within a body of water, said method comprising the steps of:

positioning a chopping tool over said submerged mass; releasing the chopping tool for downward movement toward said mass such that said chopping tool impacts and cuts through said mass, including cutting an opening in said mass by bulbous lower edges of said chopping tool to produce a clearance for the main body portion of said chopping tool, raising said tool by means of a hoisting mechanism connected to said tool; and repeating said steps of positioning, releasing, and raising until the mass is in a desired cut condition.

3. The method according to claim 1 wherein said step of impacting the chopping tool against the mass further comprises the steps of:

impacting spaced cutting tips formed by the downwardly converging edges of the flanges of a structural member against the mass to penetrate the mass; and concurrently impacting an arcuate. concave upward cutting edge formed by a web connecting the flanges against the mass to cut through the mass. 4. The method according to claim 1 and further comprising the step of:

insulating said hoisting mechanism from forces developed incident to the movement of said chopping 5 tool by interposing resilient shock-absorbing means between said chopping tool and a hoisting mechanism carrying said chopping tool.

5. The method according to claim 1 wherein said step of repeating comprises the step of shifting-said chopping tool generally horizontally relative to said mass such that said tool cuts said mass along a desired cutting path.

6. The method according to claim 5 and further including the step of locating a guide line above the water surface and aligning the guide line generally parallel to the desired cutting path to provide a visual guide for orienting the chopping tool.

7. The method according to claim 1 wherein said step of releasing comprises the step of confining said tool within a movable guide frame means disposed in said water and directed toward said mass.

cutting an opening in said structure by the bulbous bottom cutting edge of the chopping tool to produce a clearance for the main body portion of said chopping tool.

Claims

1. A method for cutting a mass which is submerged within a body of water, said method comprising the steps of: positioning a chopping tool over said submerged mass; releasing the chopping tool for downward movement toward said mass; impacting said chopping tool against said mass to penetrate and cut said mass; raising said tool by means of a hoisting mechanism connected to said tool; and repeating said steps of positioning, releasing, impacting, and raising until the mass is in a desired cut condition.

2. A method for cutting a mass which is submerged within a body of water, said method comprising the steps of: positioning a chopping tool over said submerged mass; releasing the chopping tool for downward movement toward said mass such that said chopping tool impacts and cuts through said mass, including cutting an opening in said mass by bulbous lower edges of said chopping tool to produce a clearance for the main body portion of said chopping tool, raising said tool by means of a hoisting mechanism connected to said tool; and repeating said steps of positioning, releasing, and raising until the mass is in a desired cut condition.

3. The method according to claim 1 wherein said step of impacting the chopping tool against the mass further comprises the steps of: impacting spaced cutting tips formed by the downwardly converging edges of the flanges of a structural member against the mass to penetrate the mass; and concurrently impacting an arcuate, concave upward cutting edge formed by a web connecting the flanges against the mass to cut through the mass.

4. The method according to claim 1 and further comprising the step of: insulating said hoisting mechanism from forces developed incident to the movement of said chopping tool by interposing resilient shock-absorbing means between said chopping tool and a hoisting mechanism carrying said chopping tool.

5. The method according to claim 1 wherein said step of repeating comprises the step of shifting said chopping tool generally horizontally relative to said mass such that said tool cuts said mass along a desired cutting path.

8. A method of cutting a mass which is at least partially submerged in a body of water, the method comprising the steps of: positioning over the structure a chopping tool having a main body portion and a bottom cutting edge, the cutting edge being of bulbous configuration relative to said main body portion; releasing the tool for downward movement toward the structure, and cutting an opening in said structure by the bulbous bottom cutting edGe of the chopping tool to produce a clearance for the main body portion of said chopping tool.