Anti-torpedo system
United States Patent 1191 Hicks 1 1 ANTl-TORPEDO SYSTEM Raymond M. Hicks, 4326 18th St.. N.W.. Washington, DC  
 [76] Inventor:  
 [52] US. Cl. 89/1 A; 89/41 SW [51] Int. Cl. F4lg 3/00 [58] Field 01 Search 89/1 A. 41; 340/4; 102/16 T; 114/21. 21W  
 [56] References Cited UNITED STATES PATENTS 1.195.042 8/1916 Leon 102/16 1.548.024 8/1925 Cuntz 340/4 1.635.117 7/1927 Dunmore 340/4 1.689.292 111/1928 O&#39;Neill i r i 340/4 1.865.101 6/1932 Hammond. Jr. 114/21 W 2.404.266 7/1946 Loughnan 340/4 2.513.279 7/1951] Bradley 89/41 2.668.512 2/1954 Klas 89/1 A Primary ExaminerBenjamin A. Borchelt ASA/X16111 Emminer-Charles T. Jordan Armrney. Agent. or FirmR. S. Sciascia; .1. A. Cooke EXEMPLARY CLAIM I. In an antitorpedo system of the character disclosed. in combination. a radio frequency bridge having a 1 1 Apr. 8, 1975 source of radio frequency power connected thereto. a line of reference arranged at a predetermined distance from the vessel and parallel thereto, said reference line comprising an antenna disposed beneath and in contact with the water and abeam the vessel. means for applying a radio frequency current from said source to the antenna. the ends of one of the arms of said bridge being connected to the hull of the vessel and to said antenna respectively said one arm including an electrically conductive path through the water between the antenna and said hull. means in at least one of the other arms for initially adjusting the bridge to an off balance condition. an output circuit for said bridge. a transformer in said output circuit. detector means operatively connected to the output of said transformer, a discharge tube having the control element thereof connected to the output of said detector means. the degree of initial unbalance of said bridge being insufficient to fire said tube. a plurality of explosive missiles. a plurality of guns aimed just beneath said line of reference for firing said missiles in the direction of the torpedo. and clectroresponsive firing means on each of said guns operatively connected to the plate of said tube for firing the guns when a torpedo has approached said line of reference to a point substantially subjacent with respect thereto and thereby changed the impedance of the antenna circuit and the radio frequency current flowing therein sufficiently to fire said tube.  
 3 Claims, 4 Drawing Figures PATENTEBAPR 81915 3 .875.844-  
 SHEET 1 0F 2 DETECTOR c PARATOR ECTOR INVENTOR R. M. HlCKS BY -@@/uJ- PATENTEDAPR 81975 FLEET 2 2 INVENTOR R. M. HICKS ATTOR Y5 ANTI-TORPEDO SYSTEM The invention described herein may be manufactured and used by or for the Government of the U.S.A. for governmental purposes without the payment of any royalties thereon or therefor This invention relates to an antitorpedo system and more particularly to a system for protecting a vessel against torpedo attack by firing an explosive charge into the water in the path of the oncoming torpedo from at least one gun or mortar discharge device on the vessel in response to a variation in a high frequency field set up within the water by an approaching torpedo.  
  In devices of this class heretofore devised. it has been the usual practice to protect a vessel from torpedo attack by various barriers placed about the vessel. bombs, explosive streamers and the like arranged within the water and similar devices. Such devices have not been altogether satisfactory in operation for the reason that the speed of travel of the modern torpedo has been greatly increased in recent years and the tactical methods employed in attacking by torpedo both air and sea launched have greatly reduced the effectiveness of such devices.  
  It is a primary object of this invention. therefore. to provide a system for protecting a vessel from torpedo attack which possesses all ofthe advantages ofthe prior art devices and none of the foregoing disadvantages. In accordance with a preferred embodiment of the invention the presence of the oncoming torpedo is made manifest by a change in antenna current ofa radio frequency transmitting system in which a reference line comprising an antenna is arranged within the water and a predetermined distance abeam the vessel and parallel thereto. This change in antenna current causes one or more of a plurality of guns. mortars. or other launching apparatus on the vessel to fire a missile having an explosive charge therein into the water just inside the ref erence line and in the direction from which the torpedo is approaching when the torpedo has arrived at a predetermined distance from the vessel in closely spaced adjacency to the reference line. The torpedo is thus destroyed or disabled by the explosion of the missile dis charged from the vessel within the water and without the intervention of an operator, although, if desired. an operator could be employed for controlling the discharge of the guns.  
  One of the objects of the present invention is to pro vide a system for protecting a vessel from torpedo attack and which is controlled by a radio signal continuously transmitted through the water.  
  Another object is to provide a new and improved system of detecting and destroying a torpedo upon approach to a vessel in which a salvo is automatically fired into the water from the vessel in the path of the oncoming torpedo when the signal caused by the torpedo has been modulated to a predetermined degree.  
  Still another object is to provide a gun firing system for disabling an oncoming torpedo in which the guns may be fired selectively either singly or in salvos.  
  Other objects and many of the attendant advantages ofthis invention will be readily appreciated as the same becomes better understood by reference to the following detailed description taken in connection with the accompanying drawings in which:  
  FIG. 1 is an elevational view of a vessel employing the system of the present invention in accordance with a preferred embodiment thereof;  
  FIG. 2 is a plan view of the vessel of FIG. I showing a firing arrangement of the guns under control of an operator;  
  FIG. 3 is a circuit diagram ofa firing control arrangement of the guns of the vessel in response to an underwater radio signal modulated by the oncoming torpedo; and  
  FIG. 4 is an alternative circuit diagram for automatically firing the guns when a continuously transmitted radio signal has been modulated by the torpedo Referring now to the drawings for a more complete understanding of the invention and more particularyly to FIG. I thereof there is shown thereon a vessel indicated generally by the numeral 10 having a plurality of guns 11 mounted thereon. each of the guns being adapted to fire an explosive shell 12 into the path of travel of an oncoming torpedo 13. The explosive shell I2 is provided with suitable means such, for example. as a reversed ogival nose (not shown) for causing water entry upon contact with the water surface and a time delay fuze or the like for preventing the shell from exploding until the shell has entered the water and reached a depth of submersion generally corresponding to the running depth of the torpedo.  
  On FIG. 2 is shown a circuit arrangement suitable for use with the vessel 10 and adapted to fire selectively either one or a salvo of guns II under the control of an operator. The system shown on FIG. 2 comprises a plu rality of guns or mortars ll preferably pointed down wardly toward the surface of the water and of the type adapted to be fired by an electrical impulse received over a firing circuit. Two separate systems are disclosed. one for the port and the other for the starboard side ofthe vessel. For the purpose of description corresponding parts ofthe two systems have been designated by like numerals of reference. The guns II on the port side of the vessel, for example, are shown grouped into two groupsv The guns of the forward group covering the area between the midpoint of the vessel and the bow are connected together by a conductor 14 to which a battery 15 is applied by operation ofswitches 16 or 17, as the case may be, the operation of switch 16 to closed position causing the guns in this section to fire. In a similar manner the guns 11 at the rear portion of the vessel are connected to switch 18 by conductor 19 whereby operation of switch I8 to a closed position causes the rear guns to fire. Conductor I9 is also connected to contact of switch 17. When switch 17 is closed, both guns on the forward and rear positions of the port side of the vessel are fired. The guns, it will be understood. may if desired be ofa repeating type such that repeated salvos therefrom are fired in quick successive order as long as any of the firing keys I6. 17 or 18 are closed.  
  In similar manner corresponding switches 21, 22, and 23 are employed to control the gun fire on the starbord side of the vessel.  
  Referring now to FIG. 3 there is shown thereon a gun fire control system in which the intervention of an operator is not required. The system comprises a radio frequency bridge generally indicated by the numeral 24 and having three arms, Z1. Z2, and Z3, the fourth arm comprising an antenna 25 connected thereto and arranged within the sea water and towed by the vessel from whence the circuit is completed by way of the sea water to ground 26 at the hull of the vessel. The bridge is supplied with a source of radio frequency RF substantially as shown and the arms Z1. Z2, and Z3 are adjusted in such manner that the bridge is normally slightly off balance thereby to apply a small continuously alternating high frequency current to the primary winding P of transformer 27, the secondary winding S of which is connected in a well-known manner to a rectifying detector. This arrangement provides a reference voltage to the control element of the tube 28 of insufficient value to fire the tube. Preferably. though not necessarily. a grid leak resistance 29 is connected between the control element of the tube and the cathode. The cathode filament is heated in a conventional manner as shown and the plate of the tube is connected by conductor 31 to the guns ll. the plate voltage for the tube being supplied from battery 32 by way of resistance 33.  
  The antenna is maintained outboard in predetermined spaced relation from the vessel in any convenient manner as by a paravane 20. HO. 1, a line interconnecting the paravane to the vessel and having a conductor therein for establishing an electrical connec&#39; tion to the antenna.  
  ln operation when a torpedo approaches the vessel. FIG. and moves into a position sufficiently near the antenna to change the impedance of the variable arm of the bridge 24. the output of the bridge is changed and as the torpedo moves substantially to the position with respect to the vessel shown on FIG. 1. tube 28 fires thereby firing the guns ll controlled thereby.  
  In FIG. 4 is shown an alternative firing control system suitable for use with the instant invention in which the secondary winding S oftransformer 27 is connected to the input of a comparator detector. An air core transformer 34 is employed with this arrangement. the primary winding P of which is connected across the source of radio frequency signals and the secondary winding S is connected to the comparator detector as shown. When employed with the underwater antenna 25 the radio frequency is set at an optimal value. Variations in impedance between antenna 25 and the hull of the vessel caused by modulation of the radio field by the oncoming torpedo moving into the vicinity thereof causes tube 28 to discharge and fire the guns ll.  
  The detector connected to the secondary winding S of transformer 27 is responsive to rapid changes in impedance of the antenna circuit such as those caused by the approach of a torpedo and is relatively unrespon sive to slow changes in the impedance of the antenna frequency such as may be caused by movement of the antenna with respect to the vessel or as the result of wave motion.  
  When employing automatic control for the firing of the guns. the explosive shells 12 are fired at the topedo in response to a change of predetermined character in the impedance of the antenna circuit regardless of whether the firing circuit of FIG. 3 or FIG. 4 is employed.  
  While the invention has been described with particularity. with reference to guns for firing the explosive shells. it will be understood that this is by way of example only and other instrumentalities and means may be employed for projecting the missile such, for example. as compressed air. springs, mortars. rocket launchers. and the like.  
  Obviously many modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.  
  What is claimed as new and desired to be secured by Letters Patent of the United States is:  
  1. In an antitorpedo system of the character dis closed. in combination. a radio frequency bridge having a source of radio frequency power connected thereto. a line of reference arranged at a predetermined distance from the vessel and parallel thereto. said reference line comprising an antenna disposed beneath and in contact with the water and abeam the ves sel. means for applying a radio frequency current from said source to the antenna. the ends of one of the arms of said bridge being connected to the hull of the vessel and to said antenna respectively said one arm including an electrically conductive path through the water be tween the antenna and said hull. means in at least one of the other arms for initially adjusting the bridge to an off balance condition, an output circuit for said bridge. a transformer in said output circuit. detector means op eratively connected to the output of said transformer. a discharge tube having the control element thereof connected to the output of said detector means. the degree of initial unbalance of said bridge being insuffi cient to fire said tube. a plurality of explosive missiles. a plurality of guns aimed just beneath said line of refer ence for firing said missiles in the direction of the torpedo, and electroresponsive firing means on each of said guns operatively connected to the plate of said tube for firing the guns when a torpedo has approached said line of reference to a point substantially subjacent with respect thereto and thereby changed the imped ance of the antenna circuit and the radio frequency current flowing therein sufficiently to fire said tube.  
  2. A system for protecting a vessel from torpedo attack comprising a radio frequency bridge. a line of reference arranged at a predetermined distance from the vessel and parallel thereto. said reference line comprising an underwater antenna disposed beneath the surface of the water in contact therewith and carried by said vessel in abeam relation therewith. means for ap plying a radio frequency current to the antenna, said bridge having the ends of one arm thereof connected to the hull of the vessel and to said antenna respectively said one arm including an electrically conductive path through the water and said hull. a plurality ofexplosive charges. means for directing and suddenly propelling the charges through the air outboard of the vessel and toward said line of reference in a direction such that the charges enter the water just inside the line of reference and ahead of the torpedo. and electroresponsive means operatively connected to said bridge for actuating said charge propelling means when said bridge is unbalanced by a predetermined change in the impedance of the antenna circuit and the radio frequency current flowing therein caused by said torpedo.  
  3. In a system for protecting a vessel from torpedo attack, in combination. a line of reference arranged at a predetermined distance from the vessel and parallel thereto, said reference line comprising an antenna disposed beneath the surface of the water and connected to said vessel in a manner to be towed abeam thereby. means including an antenna circuit for applying a radio frequency current to said antenna continuously. the hull of the vessel and the water between said antenna and said hull being included in the path of said current.  
  6 torpedo moves into close adjacency with said line of reference for generating a firing signal, and means operatively connected to said signal generating means for actuating the weapon hurling means in response to said firing signal.