Open loop minesweeping system

#The present invention relates to minesweeping equipment, and more particularly to equipment that will clear a body of water of mines that can be set off by influence signatures.

#A minesweeping system that creates influence signatures generally must provide a large enough influence field to be effective while still minimizing the size and weight of the equipment to make the system practical from the standpoint of the platform which controls and/or tows the system. This platform may be a ship, a helicopter, a remote controlled vehicle operating above or below the water surface, or a slow moving aircraft. Minesweeping systems generally have therefore involved a trade-off of performance vis-a-vis size and weight.

#Prior art systems to date have included sweep systems using open loop magnetic technology, wherein electrical current is distributed between two or more towed electrodes and the intervening seawater between the multiple electrodes is used as the electrical return. One such system, the Mk-105, utilizes a vehicle towed by a helicopter with a gas turbine power plant on the hydrofoil to generate electricity for the open loop electrodes. The Mk-105 system is powerful, but also quite large and heavy, thus requiring the hydrofoil vehicle. In general, however, the most efficient means to achieve a large magnetic field is to use the open loop means of generating the field. Thus, a ship or helicopter-hydrofoil system has generally been required for the towing. Further, such open loop systems require sufficient physical handling equipment to handle the two or more electrodes, including the appropriate deployment and retrieval of the multiple electrodes as well as maintaining the multiple electrodes separated from one another for proper functioning and to avoid tangle.

#FIG. 1 is a schematic view of the present invention as it would be towed through the sea water;

#FIG. 2 illustrates in detail the towed body used in the present invention;

#FIG. 3 is a side elevational view illustrating in detail certain of the fairings including the second electrode elements of the present invention as positioned along the tow cable;

#Referring to FIGS. 1 and 2, towed body 10 is illustrated which is generally shaped in a torpedo-like, streamlined fashion for smooth, fast and stable passage through the seawater 11. Body 10 when towed may be submerged, and includes rear hydrodynamic fins 12 and possibly hydrodynamic wings 13 to control the orientation, depth and direction of the towed body. As illustrated, electromechanical tow cable 14 is connected at one end to the towed body 10 at connector mechanism 15, and the other end of tow cable 14 may be connected to a winch mechanism on the towing platform (for example on a towing helicopter, not shown). The towing platform also will have means to cradle and carry the towed body 10 when not in minesweeping use from one location to another. The towing platform additionally will have power means to provide AC power of low amperage and high voltage down tow cable 14 to the towed body 10. As previously noted, the providing of AC power of low amperage to the towed body allows the power cable along tow cable 14 to be of small diameter and light weight as compared to cables providing high DC current from the towing platform to the towed body.

#Extending rearwardly from towed body 10 when it is in minesweeping operation is an insulated and waterproof, sweep separation cable 16 and the aft (first) anode electrode 17 in cable form. Cable 16 and electrode 17 may be non-buoyant to minimize size and drag, and are of standard known design. The open loop magnetic method of minesweeping requires a second electrode, but in the present invention, there is no second electrode towed behind towed body 10. Rather, a cathode electrode 18 is shown schematically in FIG. 1 extending along the electromechanical tow cable 14 in front of towed body 10. It should be understood that the anode and cathode functions may be reversed between the respective electrodes. Electrode 18 is separated from the front of towed body 10 by at least several feet. It is know to utilize a plurality of streamlined fairings along a tow cable to reduce drag and strumming, and for stabilizing the tow of body 10. In the present invention, referring to FIG. 3, a plurality of fairings 30 are mechanically attached to electromechanical tow cable 14, but at least a portion of each fairing is electrically isolated from cable 14. Each fairing 30 for example has a plastic nose piece 31 which surrounds tow cable 14, and a tail piece 32 which comprises electrically conductive metal which is electrically isolated from tow cable 14 by the plastic nose piece 31. The metal tail pieces 32 are electrically connected together by flexible electrical conductors 33 so that the tail pieces 32 of all the fairings 30 form the second electrode 18 of the present invention. Four of such fairings are shown in blown-up detail in FIG. 3, and an individual fairing is shown in perspective in FIG. 4. Insulated and waterproof separation cable 34 extends from the fairing nearest towed body 10 back to the towed body and is connected to the DC power source situated on body 10 as further described below. As shown in FIG. 4, each fairing 30 has a hole 41 for tow cable 14 to pass through plastic nose piece 31. Each fairing 30 further has a hole 42 for electrical conductors 33 which are connected to each tail piece 32 in any suitable manner.

#Second electrode 18, merely as an example, may be from fifty or less feet up to two hundred or more feet in length, and there may be for example three f airings per foot of tow cable 14, for a total of several hundred fairings. Since the fairings 30 are capable of moving to a degree along tow cable 14, permanent ring members may be swaged to cable 14 at given distances (i.e., thirty feet) to prevent the fairings 30 from excessively bunching up along cable 14. Accordingly, the several hundred electrically conductive fairing tail pieces 32, as electrically connected together by conductors 33, form the second electrode 18. Cathode electrode 18 is insulated from electrode 17, and the return path from electrode 17 to electrode 18 is through the intervening sea water 11. It will be apparent that there are not two towed cables behind towed body 10 to be separately handled and maintained in a tangle-proof state.