Airbag projectile for impeding surface vessel

Abstract

A projectile can be fired at a surface vessel and, upon impact, an air bag may be deployed almost instantaneously from underneath the vessel. Through the rapid inflation of the air bag, the stability and orientation of the target surface vessel may be disturbed. Disturbance, at a minimum, may reduce and change the trajectory of the surface vessel, but, in some circumstances, the surface vessel may be overturned. The air bag may be designed with an anti-slip coating to directly couple to the wet hull of the surface vessel. In some embodiments, the projectile may include a delay to enable the air bag to be positioned under the vessel before inflation thereof.

Description

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

(1) Field of the Invention

The invention relates to apparatus and methods for impeding motion of a water surface vessel and, more particularly, apparatus and methods for impeding the motion of a water surface vessel by inflating an air bag under the surface vessel.

(2) Description of the Prior Art

Conventional methods and devices for arresting small surface vessels include deployable nets designed to foul the propeller mechanism of a vessel, fences, inflatable bladders and fixed barriers. While generally effective at stopping small surface craft, all are limited in terms of flexibility due to their small area of effect. Stationary barriers take time to set up, restrict both desirable and undesirable maritime traffic, and are, by nature, passive defenses. Deployable nets, either shot from some launching apparatus or dropped into the water by a boat or aircraft, have limited range, cover a limited area, and require the target vessel to collide with the nets in order to be effective.

There is a need for an improved surface vessel arrestment system and method for impeding the motion of a surface vessel.

SUMMARY OF THE INVENTION

According to one aspect of the current invention, a projectile comprises an airbag; a trigger mechanism adapted to activate inflation of the airbag; and a sensor adapted to detect impact of the projectile in the water or on a surface and to trigger the trigger mechanism to activate inflation of the airbag.

According to another aspect of the current invention, a system for impeding motion of a surface vessel comprises a projectile having a sensor, a triggering device, and an airbag, wherein the sensor is adapted to determine an appropriate time to inflate the airbag, and the triggering device receives a signal from the sensor to activate inflation to the airbag.

According to a further aspect of the current invention, a method for impeding motion of a surface vessel, comprises directing a projectile toward a hull of the surface vessel; detecting either contact of the projectile with water or contact of the projectile with a surface; and inflating an airbag when the projectile is disposed in a position under one side of the surface vessel.

The above and other features of the invention, including various novel details of construction and combinations of parts, will now be more particularly described with reference to the accompanying drawings and pointed out in the claims. It will be understood that the particular assembly embodying the invention is shown by way of illustration only and not as a limitation of the invention. The principles and features of this invention may be employed in various and numerous embodiments without departing from the scope of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

Reference is made to the accompanying drawings in which is shown an illustrative embodiment of the invention, from which its novel features and advantages will be apparent, wherein corresponding reference characters indicate corresponding parts throughout the several views of the drawings and wherein:

FIG. 1 is a schematic view of an airbag projectile according to an exemplary embodiment of the current invention; and

FIGS. 2A through 2C show pictorial representation of the airbag projectile of FIG. 1 deployed to impede a surface vessel, according to an exemplary embodiment of the current invention.

DETAILED DESCRIPTION OF THE INVENTION

The following detailed description is of the best currently contemplated modes of carrying out exemplary embodiments of the invention. The description is not to be taken in a limiting sense, but is made merely for the purpose of illustrating the general principles of the invention: the scope of the invention is best defined by the appended claims.

Broadly, the current invention provides a projectile that can be fired at a surface vessel, typically at surface vessels under 25 feet. At impact, an air bag may be deployed almost instantaneously from underneath the vessel. Through the rapid inflation of the air bag, the stability and orientation of the target surface vessel may be disturbed. Disturbance, at a minimum, may reduce and change the trajectory of the surface vessel, but, in some circumstances, the surface vessel may be overturned. The air bag may be designed with an anti-slip coating to directly couple to the wet hull of the surface vessel. In some embodiments, the projectile may include a delay to enable the air bag to be positioned under the vessel before inflation thereof.

Referring now to the drawings, and more particularly to FIG. 1, an airbag projectile 10 may include an airbag portion 12 and a triggering mechanism 14. The airbag portion 12 may include an airbag 16. The airbag 16 may be, for example, a nylon conical bag containing three chemicals—sodium azide 18, potassium nitrate 20 and silicon dioxide 22. While FIG. 1 shows the chemicals 18, 20, 22 as discrete elements in the airbag 16, typically, the chemicals 18, 20, 22 may be mixed together inside the airbag 16. The chemicals 18, 20, 22 may be in a mole ratio of 2:2:1, respectively.

A heating element 24 may be disposed to warm the sodium azide 18 to about 300 C, at which point the sodium azide may decompose into sodium and nitrogen gas. The other chemicals 20, 22 in the airbag 16 may reduce the reactive sodium metal into an inert alkaline silicate, producing more nitrogen gas in the process. These reactions may be rapid, inflating the airbag 16 in less than a second.

The heating element 24 may be powered by electrical means, for example, by a battery 26 connected to the heating element 24 by wires 28. The wires 28 may pass through the airbag 16 and may break apart to separate the airbag 16 from the battery 26 when the airbag 16 is inflated.

The triggering mechanism 14 may include a sensor 30. The sensor 30 may detect impact of the projectile 10 into water 54 or may detect impact of the projectile 10 onto a surface, such as a hull 50 of a surface vessel 52 (see FIGS. 2A-2C). The triggering mechanism 14 may further include a time delay mechanism 32. The time delay mechanism 32 may provide a delay between activation of the sensor 30 and energizing the heating element 24. For example, if the sensor 30 detects that the projectile 10 has just entered the water, there may be a short delay (for example 0.5 to about 5 seconds) to permit the projectile 10 to be disposed directly under one side of the surface vessel 52. The time delay mechanism 32 may provide a shorter or no delay if the sensor 30 detects that the projectile 10 has impacted on a surface.

The airbag 16 may be housed in a housing 34. The housing 34 may protect the airbag 16 while the projectile 10 is launched to be positioned under the surface vessel 52. The housing 34 may be designed to break apart when the airbag 16 is inflated. The airbag 16 may contain an anti-slip coating 36. The anti-slip coating 36 may permit the airbag 16 to directly couple to the hull 50 of the surface vessel 52.

Referring now to FIG. 2A, the projectile 10 may be directed toward an underside of one side of the surface vessel 52. Upon impact with the hull 50 of the surface vessel 52 (or after a previously determined time delay after impact with water), the airbag 16 will rapidly (typically in about one second or less) inflate, as shown in FIG. 2B. The anti-slip coating 36 may cause the inflated airbag 16 to stick to the hull 50 of the surface vessel 52. Due to its buoyancy, the inflated airbag 16 will tend to rise to the surface of the water 54, impeding the surface vessel's 52 motion, as shown in FIG. 2C. In some embodiments, the buoyancy of the airbag 16 may cause the surface vessel 52 to overturn and capsize.

The projectile 10 may be launched toward the surface vessel 52 through the air or through the water. The projectile 10 may be launched using either energetic material or compressed gas, for example. The projectile 10 may be instrumented into unmanned autonomous vehicles (AUVs, not shown). In some embodiments, the AUV system may be particularly useful in a port security environment.

It will be understood that many additional changes in the details, materials, steps and arrangement of parts, which have been herein described and illustrated in order to explain the nature of the invention, may be made by those skilled in the art within the principle and scope of the invention as expressed in the appended claims.

The foregoing description of the preferred embodiments of the invention has been presented for purposes of illustration and description only. It is not intended to be exhaustive nor to limit the invention to the precise form disclosed; and obviously many modifications and variations are possible in light of the above teaching. Such modifications and variations that may be apparent to a person skilled in the art are intended to be included within the scope of this invention as defined by the accompanying claims.

Claims

1. A projectile for impeding a surface vessel on water, said projectile comprising:

an airbag in stowed configuration, said airbag being inflatable by reactive chemicals;

a trigger mechanism for initiating reaction of said chemicals thereby causing inflation of said airbag; and

a sensor for detecting impact of the projectile in the water and to trigger said trigger mechanism to inflate said airbag under the water adjacent the vessel.

2. The projectile of claim 1, further comprising a time delay mechanism adapted to delay triggering of said trigger mechanism responsive to said sensor detects the impact of the projectile.

3. The projectile of claim 1, further comprising a heating element for heating at least one of said chemicals in said airbag.

4. The projectile of claim 3, further comprising a battery for providing electrical current to energize said heating element.

5. The projectile of claim 1, wherein said chemicals include sodium azide, potassium nitrate and silicon dioxide disposed within said airbag.

6. The projectile of claim 1, further comprising a housing encasing said airbag.

7. The projectile of claim 1, further comprising an anti-slip coating on an exterior surface of said airbag.

8. A system for impeding motion of a surface vessel on water, comprising:

a projectile having a sensor, a triggering device, and an airbag, wherein

said sensor is adapted to determine an appropriate time to inflate said airbag, and

said triggering device receives a signal from said sensor to inflate said airbag under the water adjacent the vessel.

9. The system of claim 8, further comprising a time delay mechanism adapted to delay triggering of said trigger mechanism responsive to said sensor detecting impact of the projectile on the water.

10. The system of claim 8, further comprising a heating element for heating at least one of said chemicals in said airbag.

11. The system of claim 10, further comprising a battery for providing electrical current to energize said heating element.

12. The system of claim 8, further comprising an anti-slip coating on an exterior surface of said airbag.

13. A method for impeding motion of a surface vessel, the method comprising:

directing a projectile toward a hull of the surface vessel;

detecting either contact of the projectile with water or contact of the projectile with a surface; and

inflating an airbag when the projectile is disposed in a position under one side of the surface vessel.

14. The method of claim 13, further comprising delaying the step of inflating the airbag for a predetermined period of time after the step of detecting either contact of the projectile with water or contact of the projectile with the surface.

15. The method of claim 13, further comprising heating at least one chemical inside the airbag to initiate inflation of the airbag.

16. The method of claim 13, further comprising coupling the airbag, after inflation thereof, to the hull of the surface vessel with an anti-slip coating disposed on an exterior surface of the airbag.

17. The method of claim 13, further comprising capsizing the surface vessel due to buoyancy of the airbag inflated under one side of the surface vessel.