1. Field of the Invention
The present invention relates generally to a port security barrier system which provides protection for military and commercial ports and ships docked at these ports. More particularly, the present invention relates to a floating barrier which utilizes nylon netting to prevent a small watercraft carrying explosives or the like from damaging a military or commercial port or ships docked at these ports.
2. Description of the Prior Art
There is currently a need to protect military ships from attack by explosive laden watercraft traveling at high rates of speed. Such explosive laden watercraft may include commercial power boats, small military craft and pleasure craft. These boats are generally less than forty feet in length, have a weight of around 10,000 pounds and travel at speeds of up to 52 knots. The small watercraft threat may be defined as watercraft which have a kinetic energy threshold of approximately 106 lb-ft and are capable of achieving a kinetic energy of 2×106 lb-ft.
Port security barriers in the past have generally consisted of low freeboard float lines or log booms that mark a restricted area. However, these port security barriers are not capable of halting a deliberate attempt to penetrate the barrier
There are also higher freeboard barriers fabricated molded plastic or inflated rubber tubes that will prevent penetration of watercraft of very limited size and speed into a port which harbors military ships including aircraft carriers, destroyers, supply and troop transport ships and the like. However this type of barrier is not effective as a deterrent to larger bomb laden watercraft operating at speeds of 50 kts or more.
Further, there is a need for a port security barrier which will survive wind, waves, currents, storms and other natural adverse conditions which occur at sea. Also, the port security barrier should be environmentally friendly, that is not dangerous to marine life and the marine environment including, for example, corral reefs.
The present invention overcomes some of the difficulties of the past, including those mentioned above in that it comprises a relatively simple in design and highly effective port security barrier which prevents bomb laden waterborne craft operating at speeds around 50 knots from entering a port for the purpose of disabling and seriously damaging military ships.
The port security system comprises a continuous modular, floating barrier that is installed in lengths ranging from a few hundred feet to over a mile. Each port security barrier module of the port security system includes a capture net fabricated from nylon or other synthetic line and net support structure which operates to stop the waterborne craft and prevent entry into the port.
Each port security barrier module of the port security system has three floating segmented pontoons to support the capture net and the net support structure. The pontoons are orientated perpendicular to the capture net and the barrier's longitudinal strength member which is the main support beam for the barrier.
Port security barrier modules for the port security system may be used as gates to allow small craft to pass through the system. By positioning the pontoons perpendicular to the main support beam drag is reduced when the gate is opened and closed.
Connector assemblies are provided which are used to connect adjacent port security modules to one another. Connector elements for the connector assemblies are positioned at each end of the longitudinal strength member for the module.
The port security system also has mooring buoys located along the length of the system to hold the system in place. Mooring buoys which are positioned approximately 100 to 500 feet apart have mooring lines and anchors attached thereto to secure the port security system in a fixed position with respect to the port.
Referring to
The port security barrier 10 is assembled using the port security barrier modules 14 illustrated in
A mooring system 15 is also provided for the port security barrier 10. The mooring system 15 includes mooring buoys 16 which are positioned approximately 100 to 500 feet apart and their associated mooring lines 18 and anchors 20. As seen in
When the port security barrier 10 is fully assembled, the barrier 10 constitutes a continuous wall for the port facility which it protects extending from a low point one foot above water to a point no less than eight feet above water.
Each port security module 14 of port security barrier 10 has a support structure 22 and a capture net 24 with capture net 24 being attached to the support structure 22. The horizontal boat stopping members 25 of capture net 24 consist of a 1.125 inch diameter 12-Strand Braided nylon rope. The vertical stopping members 27 of capture net 24 consist of 0.75 inch diameter 12-Plait nylon.
Nylon was selected as the netting because of its ability to absorb energy from an attacking watercraft 12 after it is trapped by the capture net 24. Other materials which may used as netting for the port security barrier 10 may include, for example, polyester, Kevlar and Spectra. The capture net 24 has a mesh size of one foot square and extends eight feet above the still water line. The netting comprising capture net 24 is provided in lengths of 52 feet which will span over one port security barrier module 14. The overall height of capture net 24 is eight feet above water level which is higher than the bow of most small high speed watercraft. Net slack of approximately 1.5 feet is provided between adjacent port security barrier modules 14 to allow for relative motion of the port security barrier 10 caused by tide, waves and currents of the ocean. Shock cord is used to keep netting tight between adjacent modules 14.
Capture net 24 is coated to resist ultra-violet damage and increase net life.
Modules 14 adjacent to gates for port security barrier 10 have 81 foot long boat-stopping nets to provide additional stretch to improve their boat stopping ability. Small boat gates for the port security barrier 10 generally comprise a single port security barrier module 14, an underwater sinker pipe (not shown), a chain (not shown) and a pair of mooring buoys 16. Module 14 operates as a small boat gate attached to the mooring buoys with connector assemblies 52, which are directed in FIG. 1A. The pipe sinker and chain which are attached to the mooring buoys 16 provide a “back stay” mooring leg that keeps the barrier in place when the small boat gate is open.
Referring to
Pontoons 26, 28 and 30 are designed so that the water level is at approximately mid-pontoon level. Orientating the pontoons perpendicular to longitudinal strength member 32 reduces drag on port security barrier 10 when gates for port security barrier system 10 are either opened or closed. Pontoon 26 is longer than pontoons 28 and 30 to provide the buoyancy required for floatation of module 14 and to provide resistance to capsizing of module 14 in the roll direction. Pontoons 28 and 30 are shorter than pontoon 26 to: (1) reduce interference when gates are opened; (2) reduce the righting moment in the pitch direction thereby improving the operational performance of module 14 in heavy waves; and (3) reduce the resistance of module 14 to end-on-currents. Pontoons 26, 28 and 30 are fabricated from steel which is painted to help protect the pontoons from the corrosives effects of seawater.
For cathodic protection of the pontoons, anodes may be attached to the pontoons to protect the steel. Composite materials may also be used to fabricate the pontoons and protect the pontoons from corrosion caused by seawater.
Referring to
Support structure 22 includes a pair of angled support braces 40 and 42. Angled support brace 40 has its lower end attached to net support member 34 near the bottom end of net support member 34 and its upper end attached to net support member 36 near the top end of net support member 36. In a like manner, angled support brace 42 has its lower end attached to net support member 38 near the bottom end of net support member 38 and its upper end attached to net support member 36 near the top end of net support member 36.
Net support structure 22 also has a pair of support members 44 and 46 which are positioned perpendicular to longitudinal strength member 32 extending vertically upward therefrom. Support member 44 is located midway between net support member 34 and net support member 36, while support member 46 is located midway between net support member 38 and net support member 36.
As shown in
It should be noted that the components of net support structure are fabricated from extra thick wall pipe and painted on the inside and outside to resist corrosion and reduce maintenance.
At this time, it should also be noted that net support members 44 and 46 may be lengthened such that their height will be approximately the same as the height of members 34, 36 and 38. This, in turn, will result in a substantially rigid support structure for net 14. In the preferred embodiment of the present invention, the approximate height of net support members 34, 36 and 38 is 5 feet 9 inches. Net 24 is secured to the net support structure 22 including net support members 34, 36 and 38 by shackles. Shackles are also used between adjacent port security barrier modules 14 to connect their nets.
Net support structure 22 may be modified to allow for a secondary net which extends from 8 feet above the water level to 14 feet above the water level. Extending the length of support members 34, 36 and 38 as well as support members 44 and 46 and providing additional bracing will provide a means of support for the secondary netting.
Referring now to
As shown in
As shown in
Located at the ends of longitudinal strength member 32 are connector element 48 and 50. Connector elements 48 and 50 are elements of a port security barrier connector assembly 52 which allows multiple port security barrier modules 14 to be connected in the manner illustrated in
Positioned below and attached to longitudinal strength member 32 is an anti-kayak guard 54 which prevents small craft such as a canoe or kayak from slipping under port security barrier 10. Located near the top of net support member 36 is a warning light 60 which is mounted on a light support bracket 62 attached to net support member 36. Pontoons 26, 28 and 30 may have fenders/protective plates 64 affixed to their front end as shown in
Each port security barrier module 14 also has a pair of towing braces 68 and 70 which provide stability for the module 14 when the module 14 is being towed at sea. One end of towing brace 68 and towing brace 70 is attached to the rear end of pontoons 26. The opposite end of towing brace 66 is attached to pontoon 28 and the opposite end of towing brace 68 is attached to pontoon 30.
Referring now to
From the foregoing it may readily be seen that the present invention comprises an new, unique and exceedingly useful port security barrier system which provides protection for military and commercial ports which constitutes a considerable improvement over the known prior art. Obviously, many modifications of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims that the invention may be practiced otherwise than as specifically described.
| Number | Name | Date | Kind |
|---|---|---|---|
| 1151607 | Newhall, Jr. et al. | Aug 1915 | A |
| 1204547 | Corrado et al. | Nov 1916 | A |
| 1249107 | Johnson | Dec 1917 | A |
| 1353811 | Muncy | Sep 1920 | A |
| 1772888 | Elia | Aug 1930 | A |
| 2369464 | Kalnitz | Feb 1945 | A |
| 4961393 | Murray | Oct 1990 | A |
| 6591774 | Metherell et al. | Jul 2003 | B2 |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 10390404 | Mar 2003 | US |
| Child | 10828533 | US |