US 3838643 A
An explosive device comprising a linear charge in the shape of a hollow square confined between a metallic liner and a frangible non-metallic housing which breaks into small, non-lethal parts when the device is exploded, and means for detonating the charge at diagonal corners of the square. The method involves affixing the device to the interior wall of a ships hull and detonating it.
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Description (OCR text may contain errors)
United States Patent Austin etal. Oct. 1, 1974 [5 EXPLOSIVE DEVICE FOR SCUTTLING 3,185,089 5/1965 Parkhurst 102 24 HC SHIPS  Inventors: Carl F. Austin, lnyokern; Carl C. Primary l Borchelt Halsey, China Lake, both f Ca]jf Assistant ExaminerJ. V. Doramus i Attorney, Agent, or FirmR. S. Sciascia; Roy Miller;  Ass1gnee: The United States of America as L Poh] represented by the Secretary of the Navy, Washington, DC. 22 Filed: Oct. 4, 1971  ABSTRACT  APP] 186,389 An explosive device comprising a linear charge in the shape of a hollow square confined between a metallic liner and a frangible non-metallic housing which  US. Cl 102/24 HC breaks into small, nomlethal parts when the device is Cl. exploded and means for detonating the charge at Fleld of Search HC, 24, agona] orners of the quare The method involves af fixing the device to the interior wall of a ships hull and  References Cited detonating it.
UNITED STATES PATENTS 3,169,479 2 1965 Bryan 102 24 11c 2 3 Drawmg guns Pmmmw Hm I 3.838.643
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EXPLOSIVE DEVICE FOR SCU' ITLING SHIPS BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to explosive devices which will cut holes through metallic plates upon detonation and to a method for utilizing such devices for scuttling ships.
2. Description of the Prior Art The art of cutting holes through metal with explosive devices is well developed. For example, shaped linear explosive charges are used in demolition applications to penetrate the protective casing of bombs. In the drilling of oil wells and the like, shaped conical explosive charges are used to penetrate the well casing and adjacent earth formations.
The art of scuttling ships is not well developed. More specifically the art of deliberately and quickly sinking a ship by blasting a hole or holes in the hull from the interior to the exterior is not well develped. In the recent past, ships have generally been scuttled by placing a plurality of satchels of plastic explosive at various strategic positions within the hull and detonating them. This method has proven to be unreliable. Thus, a need which exists for explosive devices which are capable of quickly, safely, and reliably scuttling a ship or the like, has been realized.
Prior art munitions devices for use under water, i.e., for use in sinking ships, have been used to cut holes through the armor of ships. However, in the prior art such devices have primarily been used to cut from the exterior through armor into the interior of ships. That is, they have been triggered under water and used to blast holes from water through the hull to air. When it is desired to blast a hole from water through metal to air, either a conical jet has been used or a large amount of pressure placed on a small amount of surface area of the metal by the detonation wave of the explosion and confined by the surrounding water has been used to do an excellent job. Therefore, prior art underwater hole cutting devices have generally been designed to either concentrate the detonation wave and liner products into a pencil-like jet which impinges onto a small area of the ships surface or to simply provide a maximum of blast. When it is attemped to use such devices from the interior of a ship to cut holes from air through metal to water, the water pressure operating from the other side of the metal acts to negate the action of the concentrated detonation wave. Consequently the attempted use of such devices often results in either a very small hole or else in merely denting the hull outwardly. Moreover, such devices as conical shaped charges, because of the pencil-like character of the liner products only cut small holes when the charge does succeed in perforating the hull. Furthermore, such devices are generally made almost entirely of metallic parts and throw fragments of metal in all directions upon detonation. All of these shortcomings make prior art explosive hole cutting devices ineffective and dangerous for use in scuttling ships from the interior thereof.
SUMMARY OF THE INVENTION A device for quickly, safely, and reliably cutting holes through the hulls of ships and the like from the interior is made available by this disclosure. An explosive device according to the present invention is made up of a shaped linear explosive charge confined be tween a steel liner and a frangible housing which breaks up into small. non-lethal parts when the charge is detonated. The charge has the shape of a hollow square and is simultaneously detonated at diagonal corners. The shape of the charge and the diagonal detonation thereof causes it to cut a square hole in the hull of a ship. The frangible nature of the container enables the device to be attached to the interior of the hull of a ship and detonate while the ship is ini operation without greatly endangering the crew.
BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a top plan view of an explosive device according to the present invention.
FIG. 2. is a side elevational view of the device of FIG. 1 with portions broken away and in section.
FIG. 3 is a top plan view of the metallic liner of a device according to the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT Going first to the drawing in which like or similar parts are indicated by like numerals, FIG. 1 is a top plan view of an explosive device 11 according to the present invention. As seen from above, the device has a generally square shaped housing 12, a rectangular support 13 supporting a firing device 14, two detonating fuses l5 and 15 leading from the firing device to two collects l6 and 16 located at diagonal corners of the housing. Brackets 17, 18 and 18 are provided to fasten the device removably to the interior wall of the hull of a ship or the like. The rectangular support, the firing device, and the fuses are attached to the housing by means of cords 19, 19, 20, 20 21, 21. Cords 22, and 22 attach the fuses to the rectangular support.
Since the device is likely to be exploded while personnel are somewhere in its vicinity, it is preferable that all of the parts thus far named be frangible except for the mounting brackets which are welded to the hull. There are a wide variety of suitable frangible materials from which the parts can be manufactured. For example, the housing and the rectangular support can be either wood or plastic. The firing mechanism and collets can be a molded material such as Micarta or polyvinyl chloride. The cords are of a soft material such as nylon.
FIG. 2 is a side elvational view of the device of FIG.,
1 with portions broken away to show the interior of the device. FIG. 2 shows detonating fuse 15 with crimped on boosters at both ends leading to and terminating at a booster pellet 23 which is used to detonate an explosive charge 24. The explosive charge 24 is confined above by the undersurface of the housing and, in the portion shown, by the booster pellet and a portion of collet 16. The charge is confined below by a metallic liner 25, on one side by an outer housing wall 26, and on the other side by an inner housing wall 27. The liner is fitted into grooves in walls 26, 27 in a manner whereby a standoff volume 29 is provided. The charge, the housing walls 26, 27, the liner 25, and the standoff volume 29 extend completely around the periphery of the housing and form a hollow square. Where nails or screws would ordinarly be used, wooden dowels 28 and glue are used to fasten parts of the device together.
When an explosive device according to this invention is attached to the interior wall of the hull of a ship and the firing device 14 utilized to activate fuses 15 and the fuses simultaneously detonate booster pellet 23 and another just like it located in collet 16. The two booster pellets then simultaneously detonate the square shaped linear charge at diagonal corners. The detonation waves produced by detonation at diagonal corners proceed from both detonation points to the adjacent corners of the square at which boosters are not provided. These meeting detonation waves offset the lack of boosters in the opposite corners. Thus, when the device is activated, a hollow square of concentrated force (the jet) cuts outwardly through the metal of the hull of the ship and, at the same time, the meeting detonation wave provides a massive thrust against the center portion of the plate out free. During this action water pressure from outside the ship provides exterior confinement and prevents failure by bending. This combination of actions by the jet, detonation wave and external water pressure causes a smooth square hole with the dimensions of the square formed by the linear shaped charge to be cut in the hull of the ship.
In fabricating explosive devices according to the present invention standard firing mechanisms, fuses or delay trains, booster pellets and explosive charges may be used. This fact, coupled with the fact that the housing, collets, etc. are fabricated from inexpensive readily available materials makes it possible to fabricate such devices at very low cost. Examples of suitable explosive includes plastic bonded explosives and C-4. An example of a suitable material from which to fabricate booster pellets is plastic bonded explosive.
An explosive device according to the present invention is utilized in scuttling a ship by affixing it to an interior wall of the hull of the ship and detonating it. To insure scuttling within a set time limit and upon command a plurality of the devices may be affixed at various points with the ship whereby they can be easily reached and either centrally or individually activated. Then, if it becomes necessary to quickly scuttle the ship the devices may be activated upon orders from the ships commander.
While such devices are fabricated so as to produce only small, non-lethal debris upon detonation, because of blast personnel should not be within two compartments or-one deck and one compartment of a device when it explodes. Delay devices make it possible to activate the devices manually and then leave the immediate area before the explosive charge is detonated. It will be apparent that such devices could also be activated remotely from a central command post.
By varying the amount of explosive charge and liner dimensions steel plates of the types used in ships hulls have thicknesses of anywhere from about three-eighths inch to about 1 inch can easily be cut even when there is high pressure water located on the side of the plate opposite from the device.
In order to be effective in scuttling ships, the charge must cut all the way around the square. That is, cutting action must take place at the corners of the square as well as along its sides. The most effective means of insuring cutting action at the corners of the square was found to be that of fitting the metallic liner together at the corners as depicted in FIG. 3. FIG. 3 is a top plan view of the liner showing four sides 30, 30, 31 and 31 The side are each in the form of a V as better shown in 25 of FIG. 2. Two sides 30 and 30 each have two female V shaped notches 32, 32, 33 and 33' cut in the slope or leg of the V shape of the side which is nearest the center of the square so that the sides of the notches which are most remote from each other terminate at the extreme ends of the sides in which they are cut. The points of the female V shaped notches terminate at the centerline of liner cross section. Two other sides of the square 31 and 31 terminate in male V shaped ends cut in a manner whereby the sides of the male V's coincide exactly with the side of the female V shaped notches of sides 30 and 30. The four sides of the square are welded together.
ln addition to fitting the liner together as shown in FIG. 3, tests have shown that it is preferable to have the liner plated. Mild steel, the metal from which liners are most readily fabricated, has flaws or weak points in it due to the grain structure of the metal. When the linear charge is detonated, these weak points cause early localized jetting which interferes with and affects the total results of the jet formation process deleteriously. By coating a mild steel liner with thin coats of copper, nickel, and chromium in that order the results can be greatly improved. One specific example of a suitably coated liner is a mild steel liner about a 0.030 inch thick flash coated with a 0.0005 inch thick coat of copper, a 0.002 inch thick coat of nickel, and, finally, a 0.0005 inch thick coat of chromium. In addition to enhancing the effects of the explosion, the exterior chromium coat provides excellent corrosion resistance on the outside of the charge and precludes the need for cavity paint or similar protective coating on theinterior. Such interior coatings have proven significantly deleterious to the cutting action desired.
While the foregoing disclosure has been couched in language which describes the device as useful in the scuttling of ships, it will be obvious that such a device is useful in almost any situation where it is desirable to cut an opening from air through a structure to liquid. For example, the air to liquid cutting ability of the described device makes it useful in cutting openings through structure such as petroleum storage tanks, fuel oil tanks, fuel tanks, large pipe lines, etc., under demolition, emergency or sabotage conditions.
What is claimed is:
1. An explosive device for scuttling a ship comprisa. a shaped linear charge in the form of a hollow square and having a top, two sides, and a bottom, said charge being confined on the top and two sides by a frangible housing and on the bottom by a metallic liner fitted into the frangible housing, said liner being fonned from four rectangular pieces of mild steel bent along their longest lengths into Vs, wherein two of said pieces have two V shaped notches cut out of one slope of them in a manner wherein the most remote legs of said V shaped notches terminate at the extreme ends of said pieces and the points of said V shaped notches terminate at the center line running along the longest length of said pieces and wherein the other two of said pieces terminates in projections which match exactly the legs of said V shaped notches and are welded thereto:
b. means for affixing said charge in a position adjacent to the interior wall of the hull of a ship; and
c. means for detonating said charge simultaneously at diagonal corners of the square.
2. An explosive device according to claim 1 wherein said liner is coated with coats of copper, nickel and chromium in that order.