US3715828A - Anti-shark drogue dart - Google Patents

Abstract

A SHARPENED, METALLIC DART DART SECURED TO THE RISER LINES OF A SMALL DROGUE CHUTE IS RELEASABLY MOUNTED ON THE TIP OF A SPEAR GUNSHAFT WITH THE DROGUE CHUTE COLDED AND ELASTICALLY CARRIED ON THE SHAFT. UPON EMBEDDING THE DART IN THE SHARK''S BODY VIA THE LAUNCHED SPEAR SHAFT, AND RETRACTING THE SHAFT, THE DROGUE CHUTE IS PULLED FREE AND FILLS WITH WATER AS THE CREATURE MOVES THROUGH THE WATER. THE ENTRAINED MASS, CAPTURED BY THE CHUTE, PROVIDES AN ASYMMETRICAL DRAG TO UPSET THE HYDRODYNAMIC DQUILIBRIUM OF THE SHARK AND RENDER HIM INCAPABLE OF SWIMMING IN A COORDINATED MANNER AND TO, THUSLY, REMOVE HIM AS A DANGER TO DIVERS.

Description

ANTI-SHARK DROGUE DART Filed March 24, 1971 2 Sheets-Sheet l INVENTORS CLARENCE S. JOHNSON ARTHUR F. LANGGUTH THOMAS GLENN KEOUGH ERVIN F. JOHNSTON ATTORNEYS Feb. 13, 1973 c, JOHNSON ET AL 3,715,828

ANT I S HARK DROGUE DART Filed March 24, 1971 2 Sheets-Sheet 2,

INVENTORS CLARENCE s. JOHNSON BY ARTHUR F. LANGGUTH THOMAS GLENN KEOUGH ERVIN F. JOHNSTON ATTORNEYS "United States Patent ANTI-SHARK DROGUE DART Clarence S. Johnson and Arthur F. Langguth, San Diego, Calif., assignors to the United States of America as represented by the Secretary of the Navy Filed Mar. 24, 1971, Ser. No. 127,694 Int. Cl. A01k 81/00 US. Cl. 43-6 4 Claims ABSTRACT OF THE DISCLOSURE A sharpened, metallic dart secured to the riser lines of a small drogue chute is releasably mounted on the tip of a spear gunshaft with the drogue chute folded and elastically carried on the shaft. Upon embedding the dart in the sharks body via the launched spear shaft, and retracting the shaft, the drogue chute is pulled free and fills with water as the creature moves through the water. The entrained mass, captured by the chute, provides an asymmetrical drag to upset the hydrodynamic equilibrium of the shark and render him incapable of swimming in a coordinated manner and to, thusly, remove him as a danger to divers.

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.

BACKGROUND OF THE INVENTION Currently, there are few devices capable of effectively dealing with hostile, marine animals, in particular, sharks. One device utilizes an explosive charge that is forced against the body of a shark to blow a large hole in the creatures body. An obvious disadvantage of this device is that a large amount of blood from the gaping wound billows through the Water to attract other sharks. In addition, the sound tends to attract other sharks since they are drawn, by nature, toward sounds indicating distress or disturbance, and, the shock wave may deafen a diver. The explosive devices also are dangerous to the diver, himself, since, upon impact, the sea lance or spear shaft is recoiled from the sharks body back toward the point of launch. Another device, which has demonstrated an ability for neutralizing predacious marine creatures, is the electric anti-shark dart. While this device is quite effective for diver protection, it tends to be expensive and complicated; hence, its reliability is questionable. Compressed gas devices, shot into the body of a threatening creature, are similarly quite costly and must be delivered into the abdominal cavity of a shark to decommission him since body shorts have proven to be ineffective. None of the conventional, shark neutralizing techniques have attempted to upset the sharks hydrodynamic equilibrium to render them incapable of controlled motion.

SUMMARY OF THE INVENTION The present invention is directed to providing a device for ensuring the disorientation of the hydrodynamic equilibrium of marine animals and includes a dart shaped to facilitate its insertion and resist its Withdrawal from the animals body, and a drogue chute joined to the dart having the capability for increasing its lateral dimensions as the animal pulls it through the water to entrain a water mass to ensure the animals disorientation. As such, the device is deployable at long range to afford safety to the diver, and, because of its simplicity, is inexpensive.

The prime object of the invention is to provide a device for neutralizing the threat presented by hostile, marine creatures.

Another object of the invention is to provide a dartdrogue chute combination producing an asymmetrical drag on a shark destroying its hydrodynamic equilibrium.

Still another object of the invention is to provide a device which is deployable by conventional spear guns and sea lances.

Yet another object is to provide a shark neutralization device that is effective irrespective of the point of attachment on its body.

Still another object is to provide a device for neutralizing predacious marine animals which by its simplicity is inexpensive.

A further object is to provide a device for neutralizing hostile, marine animals that is small in size enabling its inclusion as standard equipment for divers.

These and other objects of the invention will become more readily apparent from the ensuing description when taken with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an isometric depiction of the invention operationally deployed.

FIG. 2 is an isometric depiction of the invention mounted on the shaft of a spear gun.

FIG. 3 is a top view of the dart.

FIG. 4 is a side view of the dart.

FIG. 5 is a frontal view of the dart.

FIG. 6 is a top view of the drogue chute.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings, the principal components of the invention are a metallic dart 10 and a drogue chute 20 which functionally cooperate, in a manner to be described below, to hydrodynamically unbalance and create a preoccupying distraction for the shark.

The dart, in its preferred form, is a triangularly shaped, sheet-metal stamping. Since the invention is to be used in a marine environment, stamping the dart from a noncorrosive or corrosion-resistant material serves to increase its useful life. The dart is bent to form a pair of rightangle triangle surfaces 11 and 12 by longitudinally folding the metal sheet along a pair of creases 11a and 12a. The creases give the dart greatly increased strength to prevent buckling as the dart penetrates the tough skin of a shark.

Along the trailing edges of each of the triangularlyshaped surfaces, a fin surface 13 or 14 acutely diverges from the longitudinal axis of the dart, and a pair of cuts 13a or 14a allows a complete separation of each fin surface from a longitudinally extending panel member 15. Noting FIG. 4, in particular, the fin surfaces are shown acutely diverging upward in the same direction. Such an orientation tends to direct the dart in a curved path as it enters the sharks body to make withdrawal of the dart more difficult. The diverging fin surfaces also impede withdrawal in much the same manner as do the barbs on a conventional arrowhead.

The forward portion of the panel member is tapered in a tip 16 preferably honed to facilitate penetration. A pair of holes 15a and 15b are punched in the panel member in an area between the darts centroid, or center of gravity, and its tip.

A small cable 17 is strung through holes 15a and 15b and anchored by knotting its free end to prevent its return through the holes. Due to the location of the anchoring point in front of the centroid, when a dragging force is exerted on the cable, this force is translated into a rotational force. The rotational force tends to rotate the dart further impeding its withdrawal and to more securely retain it in the animals body. The location of the holes is critical since having the cables anchor point at or behind the darts centroid otherwise would allow the extraction of the dart as the shark violently maneuvers to shake off the drogue chute.

The rear portion of body member 150 is retained free of protuberances, burrs, or other imperfections which would render the rear portion unsuitable for use as a mounting surface for mating with a slot on a spear shaft. The rear portion is, optionally, slotted, cup-shaped, or similarly configured, to accommodate its being releasably seated on the tip of a shaft to ensure the retention of the dart in the animals body while the shaft is being withdrawn.

A drogue chute 20 is fashioned from a single panel of nylon or rayon fabric in any one of a variety of configuration, a pentagon shape being shown in FIG. 6. A fabric or metal reinforcing eye 21 is provided at the apex of each of the corners to prevent ripping of the chute as it is being dragged through the water and a riser line 22 is tied to the panel through each eye. At their opposite ends 22a, the lines are gathered together and are joined to the cable 17 to link the chute and the metallic dart as a functionally cooperating unit.

If it is suspected that sharks, or other hostile creatures, are to be encountered, a spear shaft 25, provided with a suitably sized slot 25a on its tip, is fitted with a dart by sliding rear portion 150 in slot 25a. Drogue chute 20 is folded on itself with its canopy extending toward the dart and overlapping the riser lines along the longitudinal reaches of the shaft. The riser lines are slightly stretched to retain the dart in slot 25a and the folded chute is held on the shaft by several rubber bands 25b. The aggregate elastic holding force exerted by the rubber bands is sufficient to maintain the chutes folded relationship, yet is sufficient to allow the release of the chute after the dart has been implanted.

Once mounted on the shaft, as outlined above, the invention provides a high degree of safety. Should a shark approach, the invention is deployed at long range and the dart is implanted in the beasts body. After the drogue chute pulls free, and as the animal continues his motion through the water, the chute fills with water. A substantial water mass is entrained in the chute producing as asymmetrical drag. Where the dart-chute combination is attached to the sharks body is not critical since, irrespective of its location, the unbalancing effect is the same. Because sharks are in constant motion to force water through their gills, they become distracted as a result of their hydrodynamic disorientation. The sharks preoccupation with overcoming the drag substantially removes the shark as being a threat to the diver. Other sharks have been observed to become attracted to the animal trailing the drogue chute due to its erratic swimming patterns. Such swimming patterns naturally convey to the other sharks the apparent fact that a sick, helpless, or injured member is amongst them, and they have been frequently observed to attack this shark. Thus, the eator becomes the eatee and the diver is free to depart in the ensuing confusion.

A further advantage to using the invention resides in its quiet, long range deployment. Since the invention is constructed of an appropriately configured small sheetmetal dart and small section of fabric, the invention is inexpensive and not cumbersome.

Obviously, many modifications and variations of the present invention are possible in the light of the above teachings, and, it is therefore understood that within the scope of the disclosed inventive concept, the invention may be practiced otherwise than as specifically described.

What is claimed is:

1. A device for ensuring the disorientation of the hydrodynamic equilibrium of marine animals comprising:

a dart fabricated from a piece of sheet-metal having at least one longitudinal crease to provide inherent strength, a sharpened tip to facilitate insertion in the body of said marine animal, and having at least one fin surface on the trailing edge of said dart diverging from the longitudinal axis to resist withdrawal from the body of said marine animal and a drogue chute joined by its riser lines to said dart and configured for increasing its lateral dimensions as said marine animal pulls it through the water to entrain a water mass for ensuring said disorientation.

2. A device for ensuring the disorientation of the hydrodynamic equilibrium of marine animals comprising:

a dart fabricated from a piece of sheet-metal having at least one longitudinal crease to provide inherent strength, a sharpened tip to facilitate insertion in the body of said marine animal, and at least one fin surface on the trailing edge of said dart diverging from the longitudinal axis to resist withdrawal from the body of said marine animal;

a drogue chute joined by its riser lines to said dart and configured for increasing its lateral dimensions as said marine animal pulls it through the water to entrain a water mass for ensuring said disorientation; and

a cable connected to said riser lines and to said dart between said sharpened tip and the centroid of said dart, upon embedding said dart in said marine animal, the drag imposed by the entrained water mass tends to rotate said dart, further ensuring resistance to said withdrawal.

3. A device according to claim 2 further including:

means ensuring the remote delivery and said embedding of said dart having an anterior portion slotted to releasably hold said trailing edge and means elastically securing said drogue chute in a folded relationship on the ensuring means and upon said embedding releasing the folded drogue chute to allow its filling with water to entrain said water mass.

4. A device according to claim 3 in which said ensuring means is a conventional spear gun shaft modified to accommodate said dart.

References Cited UNITED STATES PATENTS 3,039,419 6/ 1962 Rimar 43-6 3,210,880 10/1965 Grenier 43-6 3,532,375 10/1970 Heartness 43-6 3,532,375 10/ 197-0 Hartness 436 3,586,332 6/1971 Alban 436 WARNER H. CAMP, Primary Examiner

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