US3680161A

US3680161A - Anti-swimmer buoy

Info

Publication number: US3680161A
Application number: US727742A
Authority: US
Inventors: James C Bladh
Original assignee: US Department of Navy
Current assignee: US Department of Navy
Priority date: 1968-05-08
Filing date: 1968-05-08
Publication date: 1972-08-01
Anticipated expiration: 1989-08-01

Abstract

A swimmer deterrent device comprising a float, an anchor, a lightweight line therebetween, and a plurality of swimmer impaling grapnels attached to said line are so constructed as to provide a compact assemblage when stowed prior to use.

Description

United States Patent Bladh 51 Aug. 1, 11972 [54] ANTI-SWIMMER EUUY [72] Inventor: James C. Bladh, Vernon, Portsmouth, England [73] Assignee: The United States of America as represented by the Secretary of the Navy 22 Filed: May 8,1968

21 App1.No.:727,742

[52] 11.5. C1. ..9/8 R, 102/11 [51] Int. Cl.i....B63b 21/52, 863g 13/00, B63b 17/00 [58] Field ofSearcli ..102/11; 114/241;9/8

[56] References Cited UNITED STATES PATENTS 5/1917 McGray ..102/11 8/1918 Steinmetz ..102/11 1,337,920 4/1920 Kohler ..102/11 1,531,550 3/1925 Glennon ..102/11 2,996,006 8/1961 Muzzey, Jr ..102/11 FOREIGN PATENTS OR APPLICATIONS 5,672 3/1912 Great Britain ..102/1 1 20,715 10/1915 Denmark ..102/11 Primary Examiner-Benjamin A. Borchelt Assistant Examiner-Thomas H. Webb Att0rney-L0uis A. Miller, Don D. Doty and William T. Skeer 5 7 ABSTRACT A swimmer deterrent device comprising a float, an anchor, a lightweight line therebetween, and a plurality of swimmer impaling grapnels attached to said line are so constructed as to provide a compact assemblage when stowed prior to use.

9 Claims, 6 Drawing Figures PATENWDAUB 11972 3,680.161

sum 1 or 2 INVENTOR.

PATENTEDAUQ 1 1912 SHEEI 2 0F 2 J/mfj CZ B/a/ INVENTOR.

ANTI-SWIMMER BUOY The invention described herein may be manufactured and used by or fore the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

This invention relates to an article of manufacture particularly adapted to be placed about a selected area in a body of water to deter penetration thereof by swimmers. Such devices have particular utility in modern inshore naval warfare as an individual part of a screen to protect a naval ship or other objects of military significance.

It frequently becomes necessary for a ship to lie offshore of enemy occupied territory. In such circumstances the ship is vulnerable to attack by swimmer demolition teams, who, under the cover of darkness, may attach explosive charges to the hull of the ship and escape undetected. Various attempts to counter this threatening contingency in the past have employed the use of nets, electrically charged screens or wires, and magnetic and sonic detection equipment. While each of the known deterrents have proven efiective to a limited degree, each requires a considerable expenditure of either manpower or bulk storage in installing and operating the deterrent device.

Some of the prior art screen type deterrents restrict the mobility of the vessel being protected, thereby making it more vulnerable to air and naval attack. Others require auxiliary power supplies to electrify them, which create easily detectable sonic and electrical emissions betraying the presence of the protected vessel.

A need has therefore continued to exist for a simple and easily installed device capable of detering or preventing approach by swimmers to a designated area. Accordingly, this invention has as one of its objects the provision of an improved, easily installed and compact deterrent device which will overcome the aforementioned inadequacies of the prior art devices.

A further object of the present invention is the provision of a swimmer deterrent device which will be entirely passive and require no shipboard power source.

Another object of this invention is the provision of an effective swimmer deterrent device which will not interfere with the mobility of a naval vessel protected thereby.

A still further object of this invention is the provision of a swimmer deterrent device which may be conveniently transported and stored aboard ship without interfering with the normal naval functions thereof.

Other objects and many of the attendant advantages will be readily appreciated as the subject invention becomes better understood by reference to the following detailed description, when considered in conjunction with the accompanying drawings wherein:

FIG. 1 shows a plurality of the devices of the invention as they might appear in operation;

FIG. 2 shows how the devices of the invention are installed to protect a naval vessel;

FIG. 3 shows a single personnel grapnel;

FIG. 4 depicts a single personnel grapnel protectively encased;

FIG. 5 illustrates a plurality of encased grapnels joined for purposes of assembly; and

FIG. 6 is an illustration, partially in sections, of the assembled device of the invention.

As shown in FIG. 1, the device of the invention comprises a float 11 joined via line 12, to anchor 13. At intervals along line 12 personnel grapnels are attached. Swimmers unfortunate enough to be snared by grapnels l4 suffer painful lacerations as a result of being so ensnared, or, in the case of swimmers wearing underwater diving gear, have their clothing and breathing apparatus punctured. The swimmers attempts to free himself of the ensnarement betrays his presence to the shipboard watch, thereby, in many instances, permitting capture and interrogation.

As shown in FIG. 2, the devices of the invention are placed in several rows, as shown by floats 11, about ship 15 being offshore of land 16. The lack of interconnection between individual devices permits the deployment thereof in such a fashion as to afford maximum protection from the most likely direction of approach, or to offer maximum protection to critical areas of the ship being guarded. The most frequent deployment of the devices is to completely encircle the ship being protected, as illustrated.

The individual grapnel 14, one preferred form thereof is shown in greater detail at FIG. 3, comprises an eye 17. A shank portion 18, formed integrally with eye 17 at the near end, and bifurcated at the remote end, has each remote end brought back toward eye 17. Each of said end portions lie in a common plane containing the shank portion 18 and terminate in a barb l9. Said barb l9 hinders the withdrawal of the grapnel 14 when imbedded. Barbs 19, as well as the swimmer engaging surfaces of alternate constructions of grapnels 14, are made extremely sharp to effect ease of penetration and, as a result, are difficult to handle in assembly, cause damage to line 12 during storage, if exposed thereto, and make the portion of line 12 carrying them subject to entanglement. These undesirable effects are minimized, and for practical purposes eliminated, by encasing the individual grapnels 14 as shown in FIG. 4.

As illustrated, grapnel 14 is encased, for example, by suitable state-of-the-art molding technique, in a highly water soluble pellet 21. The encasing pellet 21 is shaped to permit eye 17 of grapnel 14 to remain exposed for the purpose of attaching line 12 therethrough. A depression 20 in each face of pellet 21 permits the joining portion of line 12 to be stored therein, as will now be explained.

FIG. 5 shows a plurality of pellets 21 joined by a predetermined length of line 12. The eye 17 of each encased grapnel 14 is threaded with line 12. The desired relative positions of the encased grapnels 14 to one another is obtained by crimping a split weighted sphere 22 about the line 12 in close proximity to the grapnels 14 to prevent relative movement of the grapnels 14 therealong. Sphere 22 may be made of any suitable material such as, for example, lead or metalized plastic the principal criterion being deformability sufficient to permit a crimping installation thereof.

Referring to FIG. 6, it is seen that float 11 has an axially extending cylindrical portion 23 defining a passage therethrough. The stem of anchor 13 extends into the lower portion of cylinder 23 where it is secured by a removable pin 27 cooperating with suitable aperatures in float 11 and anchor 13. As depicted, anchor 13 is of the mushroom type and closely conforms in shape to the configuration of float ll. Anchor 13 is made from any convenient massive material and may be a sand filled plastic material, if desired, to reduce the likelihood of detection of the ship l5s anchorage even after the ship has changed location. The ring 26 of anchor 13 is secured by knoting to line 12.

Above ring 26, in cylindrical portion 23 of float 11, are stacked a plurality of pellets 21. The line 12 joining adjacent pellets 21 lies within the adjacent depressions 20. Line 12 is attached to float l 1 by extending through an apertured plug 29, which may be of the same materials as pellet 21 and being knotted about a transversely extending pin 24. The purpose of plug 29 is to contain the upper end of line 12 within cylindrical portion 23 during storage and is therefore a tighter fit within cylindrical portion 23 than pellets 21.

Float 11, it is observed in FIG. 6, is hollow and the buoyant void is not penetrated by either of the transversely extending pins 24 or 27. To permit deliberate sinking of float 11 it is made of a frangible material easily broken by small arms fire. If desired, float 11 may have suitable water soluble plugs 28 so constructed as to dissolve after a predetermined length of time, thereby sinking float 11. Float 11, as well as anchor 13, may be color coded to indicate the depth of water for which the device is constructed, the number or type of grapnels 14 contained therein, the time required for plugs 28 to dissolve, or other parameter of operation desired.

A minimum crew may install the devices from a small boat and, in operation, the devices are dropped over the side, after removing pin 27, in the desired location. Pin 27 may be removed after placement by means of unillustrated lanyard, if desired. Anchor 13 sinks carrying line 12 and attached encased grapnels 14 thereafter. Pellets 21 dissolve in the water exposing grapnels l4. Grapnels l4 and line 12 may be colored to render visual detection by swimmers difficult. If it is necessary for ship to weight anchor and get under way on short notice, as is often the case in inhospitable anchorages, the floats may be shattered by small arms fire or may be abandoned without deliberate destruction. The frangible construction of float 11 and the light weight of line 12, unlike prior art net deterrent devices, offer negligible resistance to the passage of ship 15. If not deliberately sunk, floats ll equipped with plugs 28 will sink after a predetermined passage of time.

The foregoing description taken together with the appended claims constitute a disclosure such as to enable a person skilled in the marine engineering arts and having the benefit of teachings contained therein to make and use the invention. Further, that the structure herein described meets the objects of invention, and generally constitutes a meritorious advance in the interdiction device arts unobvious to such a skilled marine engineer not having the benefit of the teachings contained herein.

What is claimed is:

l. A swimmer deterrent device comprising:

a float having wall portions enclosing a buoyant void therein and providing an axially-extending, cylindrical passage therethrough;

an anchor means having a shape closely conforming to the lower external surface of said float, a stem portion extending within said cylindrical passage, and a line attachment means connected to the upper end of said stem portion;

removable fastening means extending through the wall portions of said float and through the stem portion of said anchor means for removably securing said float to said anchor means;

a line of predetermined length disposed within said cylindrical passage and connected between said line attachment means and said float; and

a plurality of grapnel means attached to said line and disposed at predetermined intervals therealong and disposed within said cylindrical passage when said anchor means is secured to said float by said removable fastening means, and disposed beneath said float with said line when said removable fastening means is removed to free said anchor means.

2. A swimmer deterrent device according to claim 1 in which said removable fastening means is a transversely extending pin means slidably disposed in cooperating apertures in said wall portions of said float and said stem portion of said anchor means.

3. A swimmer deterrent device according to claim 1 in which said float means includes water soluble plugs located in said wall portions thereof and communicating with said buoyant void enclosed thereby and made of a material which will dissolve after a predetermined exposure to water to flood said buoyant void and thereby sink said float.

4. A swimmer deterrent device according to claim 1 in which said anchor is made of a nonmetallic material with a void therein filled with nonmetallic, heavierthan-water material.

5. A swimmer deterrent device according to claim 1 in which said grapnel means are encased within water soluble material.

6. A swimmer deterrent device according to claim 5 in which said encased grapnel means have the general shape of the cross section of the said cylindrical passage and are loosely stacked therein.

7. A swimmer deterrent device comprising:

a float having an axiallyextending, cylindrical passage therethrough;

an anchor means removably secured to said float having a line attachment means in cooperating proximity thereto;

a line of predetermined length disposed within said cylindrical passage and joined to said line attachment means at one end and attached to said float at the other end; and

a plurality of grapnel means encased in a water soluble pellet having the general shape of the cross section of said cylindrical passage, said encased grapnel means being attached to said line and disposed therealong in a predetermined relationship to one another and having depressions in the faces thereof for the containment therein of the line between adjacent ones of said grapnel means when stacked loosely within said cylindrical passage.

8. A swimmer deterrent according to claim 7 in which said encased grapnel means are joined to said line by a metallic member crimped about said line so as to form a closed loop therein.

9. A swimmer deterrent device according to claim 8 in which said grapnel means comprise bifurcated, pointed, barbed preforms, with the ends thereof being in a common plane.

Claims

1. A swimmer deterrent device comprising: a float having wall portions enclosing a buoyant void therein and providing an axially-extending, cylindrical passage therethrough; an anchor means having a shape closely conforming to the lower external surface of said float, a stem portion extending within said cylindrical passage, and a line attachment means connected to the upper end of said stem portion; removable fastening means extending through the wall portions of said float and through the stem portion of said anchor means for removably securing said float to said anchor means; a line of predetermined length disposed within said cylindrical passage and connected between said line attachment means and said float; and a plurality of grapnel means attached to said line and disposed at predetermined intervals therealong and disposed within said cylindrical passage when said anchor means is secured to said float by said removable fastening means, and disposed beneath said float with said line when said removable fastening means is removed to free said anchor means.

4. A swimmer deterrent device according to claim 1 in which said anchor is made of a nonmetallic material with a void therein filled with nonmetallic, heavier-than-water material.

7. A swimmer deterrent device comprising: a float having an axially-extending, cylindrical passage therethrough; an anchor means removably secured to said float having a line attachment means in cooperating proximity thereto; a line of predetermined length disposed within said cylindrical passage and joined to said line attachment means at one end and attached to said float at the other end; and a plurality of grapnel means encased in a water soluble pellet having the general shape of the cross section of said cylindrical passage, said encased grapnel means being attached to said line and disposed therealong in a predetermined relationship to one another and having depressions in the faces thereof for the containment therein of the line between adjacent ones of said grapnel means when stacked loosely within said cylindrical passage.