Underwater net protection system

#The present invention relates generally to use of netting to protect underwater located facilities, such as commercial seawater vessels and Navy ships for homeland security purposes.

#There are various systems, methods and/or devices already well known which may be or have been utilized to protect underwater located items such as the hulls of sea vessels in port or other facilities associated therewith, including a buoy, dock area, riverbank, etc. However use of such facilities for protection purposes would not provide damage deterrence measures by timely indicating precise location of attempted infiltrations so as to allow for rapid directed response.

#An important object of the present invention is to not only provide protection against damage to underwater facilities, such as ship hulls, but to also indicate the location of an attempted unauthorized penetration of protective netting as well as to deter damage threats by use of telecommunication lines for example and nuclear water intake/discharge facilities.

#A more complete appreciation of the invention and many of its attendant advantages will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawing wherein:

#FIG. 1 is a partial underwater view extending from a dock to a net to form a protected underwater zone pursuant to the present invention;

#FIG. 2 is an enlarged partial section view taken substantially through a plane indicated by section line 2—2 in FIG. 1; and

#Referring now to the drawing in detail, FIG. 1 illustrates an underwater protective zone 10 extending between a dock 12 and flexible netting 14 extending vertically upward from underwater anchor locations 16. Pursuant to the present invention, protection is provided for the underwater zone 10 encircled by the netting 14 as hereinafter explained, so as to deter attempted damage and locate attempted points of entry for purposes of damaging the hull of a sea vessel which may be docked in the zone 10, such as Naval ship or any other facility such as telecommunication and nuclear water intake/discharge devices.

#The netting 14 is anchored at the spaced underwater locations 16, as diagrammed in FIG. 3. Penetration attempts and penetration damage to the netting 14 positioned over the anchor locations 16, such as a hole 20 for example, is monitored by a system 18. The bottom portion 19 of the netting 14 is made of substantially heavier material than the rest of the netting 14 so as to resist or prevent lifting thereof from the anchor point locations 16. The system 18 includes components generally known in the art such as a multiplexer 21 having a light source 22 and an optical time domain reflectometer 23 to which an indicator 24 is connected as diagrammed in FIG. 3. The precise location of the hole 20 in the netting 14 as well as any other locations at which penetration is attempted is thereby indicated as hereinafter referred to.

#Also pursuant to the present invention, the netting 14 is constructed so as to exhibit a relatively high strength to not only resist damage, but to also accommodate damage indicating signal transmission in the event that damage inflicting penetration of the netting occurs. Toward those ends, the netting 14 is made from elongated netting elements 26, cross-fastened to each other. Each of such netting elements 26 as illustrated in FIG. 2, has a strong tubular portion 28 made of protective material for an optical fiber signal line 30 extending therethrough with a reinforcement member 29 in parallel therewith. Such netting 14 is connected by a bi-directional optical coupler 31 to the multiplexer 21 as shown in FIG. 3. The optical fiber signal lines 30 extend through such coupler 31 into the multiplexer 21 having the light source 22 connected thereto and the optical time domain reflectometer 23 of the system 18, so as to transmit damage indicating optical signals thereto from the netting 14. The signal generated by the light source 22 is passed through the multiplexer 21 which outputs optical signals through the bi-directional optical coupler 31 with approximately 10% of the signal going to the optical time domain reflectometer 23 and the balance passing through each optical fiber signal line 30 in turn. The reflected signal is passed back through the bi-directional optical coupler 31 to the optical time domain reflectometer 23 to calculate a delta time signal which is compared to a baseline so as to indicate an event on the indicator 24.