Abstract:
An appended pod underwater gun mount for a submersible host vessel includes a strut member having a base end fixed to an outer hull of the submersible host vessel and a distal end protruding outwardly from the host vessel, the distal end being angled with respect to the base end, and an ammunition housing moveably fixed to the distal end of the strut member. A train control mechanism is positioned between the strut member and the ammunition housing for controlling the horizontal rotation of the ammunition housing with respect to the host vessel, and a tilt control mechanism is positioned between the strut member and the ammunition housing for controlling the vertical rotation of the ammunition housing with respect to the host vessel. A flexible boot is connected to the ammunition housing and surrounds each of the train control mechanism and the tilt control mechanism to protect the mechanisms from an underwater environment. The ammunition housing is movable both vertically and horizontally with respect to the distal end of the strut member and is spaced apart from the host vessel so as to avoid contacting the host vessel during directional movement of the ammunition housing.

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 
     This invention generally relates to an appended underwater gun mount. More particularly, the invention relates to an appended underwater gun mount for both mounting and controlling an underwater gun so as to be able to engage and destroy attacking torpedoes. 
     (2) Description of the Prior Art 
     The current art for anti-torpedo devices is under investigation by Naval engineers in several countries who are investigating the technical and operational problems associated with torpedo defense. Efforts to defend ships and submarines against attacking torpedoes have resulted in a number of concepts for inclusion within shipboard Torpedo Defense Systems (TDS). Those concepts include sensors for detecting the sound of an incoming torpedo, development of recommended evasive maneuvers to avoid such a weapon, deployment of countermeasures to decoy the torpedo, and anti-torpedo weapons to destroy it before it strikes its intended target. Anti-torpedo weapons that are being investigated or developed include guns that are capable of firing underwater. Typically, these are medium caliber, projectile firing guns that can launch a stream of bullet-like objects at a very high velocity in rapid sequence. Such guns are envisioned as being used underwater against attacking torpedoes in a manner similar to anti-air missile systems such as the PHALANX close in weapons system (CIWS) against incoming airborne missiles. 
     The concept of using an underwater “machine gun” to destroy an attacking torpedo is appealing because it provides a positive and conclusive defensive response to such a situation. If the direction, or bearing, of an incoming torpedo is determined by a sensor on board a targeted vessel, requisite response action is to aim the gun and direct the release of its projectiles towards the threat. That process, however, is a complex function, composed of the combination of inter-related launcher, fire control, and operability issues that are all technically challenging. The first is the problem of providing a suitable launcher, or mounting apparatus, for containment of the gun and its ammunition. The gun mount must be capable of being controlled or moved into a position that will point the barrel of the gun towards an attacking torpedo, in accordance with an appropriate fire control solution. 
     Since projectiles fired from an underwater gun, or any type of conventional gun, are not controllable after release, the physical position of the gun barrel determines the direction subsequently taken by the shot. Bullets shot from guns are “unguided missiles”, subject to ballistic influences such as gravity, drag, and the like, after leaving the barrel. Therefore, the gun mount must have sufficient flexibility of movement to allow the muzzle of the gun to be pointed towards any direction from which a torpedo attack is probable. 
     While a torpedo may strike any part of the hull of a targeted vessel, it is generally considered that the area of greatest danger from a modern torpedo is astern. One reason is that the stern of a ship, or a submarine, is the location of the screw(s) or propulsors that drive it through the water. A great deal of energy (acoustic and other) is transferred from the vessel to the surrounding medium at that location. Modern torpedoes are designed to sense and seek such energy, and thus, a homing torpedo is likely to attack from astern, unless measures have been taken, and have been successful, to eliminate that stimulus. 
     Another reason for expecting a torpedo attack from astern is that a common tactic for any ship, if alerted to impending danger, is to turn away from an incoming weapon. That is a natural reaction, and it is logical to minimize the relative velocity between a weapon and its target by attempting to outrun it. Also, turning away from the torpedo presents a much smaller aspect or cross section. Therefore, the ship&#39;s own maneuvers may steer the danger area, intentionally, to the stern. 
     Accordingly, a need in the art exists in which an anti-torpedo gun must be able to deploy a field of fire that fills a conical volume of space astern of a vessel that is host to such a defensive system. An obvious problem with respect to implementation of that capability is that the stern of a ship is the location of control and propulsion mechanisms that would be in the way of any hull mounted launcher aimed astern. Location of a gun mount aft of those mechanisms is impractical, because the stream of gunfire would issue directly into the turbulence of the ship&#39;s wake. A gun mount configured as a towed body would also be impractical, because the precise location and attitude of the module would be variable and uncertain, and deployment would be difficult. Accordingly, it is the inventor&#39;s discovery that the functional capability that is needed to engage attacking torpedoes is a hull mounted, controllable gun mount that can fire past, or around, the screws and control surfaces of the host vessel. 
     The following patents, for example, disclose various types of anti-torpedo devices, but do not disclose a hull mounted, controllable gun mount that can fire past, or around the screws and control surfaces of the host vessel. 
     U.S. Pat. No. 3,875,844 to Hicks; 
     U.S. Pat. No. 4,215,630 to Hagelberg et al.; 
     U.S. Pat. No. 4,855,961 to Jaffe et al; and 
     U.S. Pat. No. 5,341,718 to Woodall, Jr. et al. 
     Specifically, the patent to Hicks discloses an anti-torpedo system having, 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 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 electro-responsive 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. 
     The patent to Hagelberg et al. discloses a ship anti-torpedo system including a detecting device for detecting and locating an incoming threat, such as a torpedo, and an interrelated missile launching and control system for firing at least one warhead carrying missile into the path of the oncoming threat, the missile having an active acoustic fuse system including a highly directional sensing system for continuously monitoring the position and proximity of the incoming threat and for detonating the warhead at the optimum proximity of the incoming threat with the missile. The missile floats at a predetermined depth determined by the predetermined depth of the torpedo to be intercepted. 
     Jaffe et al. discloses an imaging apparatus including an array of transmitters for simultaneously transmitting more than two coded signal beams in different directions to cover different regions of a field of view, said beams being modified by objects within said field of view, signal means for providing individual coded signals to respective transmitters, at least one receiver for simultaneously receiving plural coded modified signals derived from the coded signal beams, and a processor for separating the plural coded modified signals of different codes and processing them into an image signal. 
     Woodall, Jr. et al. discloses an acoustic decoy round ejected by a launcher for flight above water from a sea-going vessel, the round impacting at the water surface to cause separation of a payload from a forward section of the round that is also separated from a flotation anchor tethered to the payload and fins which stabilize launched flight of the round prior to impact. The separated payload submerges from the flotation anchor at the water surface location to a tethered depth within the water from which a decoy signal is emitted. 
     It should be understood that the present invention would in fact enhance the functionality of the above patents by providing a hull mounted, controllable gun mount that can fire past, or around, the screws and control surfaces of the host vessel so as to be able to engage and destroy attacking torpedoes. 
     SUMMARY OF THE INVENTION 
     Therefore it is an object of this invention to provide a hull mounted, controllable gun mount. 
     Another object of this invention is to provide a hull mounted, controllable gun mount for engaging and destroying attacking torpedoes. 
     Still another object of this invention is to provide a hull mounted, controllable gun mount which directs an unobstructed line of fire at objects, underwater, closing from astern of a host vessel. 
     A still further object of the invention is to provide a hull mounted, controllable gun mount which facilitates converging gun fire from two controllable gun mounts. 
     Another object of the invention is to provide forward and aft firing guns, co-located within the same gun mount. 
     Yet another object of this invention is to provide a hull mounted, controllable gun mount which is simple to manufacture and easy to use in any of a plurality of selected or necessary environments. 
     In accordance with one aspect of this invention, there is provided an appended pod underwater gun mount for a submersible host vessel. The appended pod underwater gun mount includes a strut member having a base end fixed to an outer hull of the submersible host vessel and a distal end protruding outwardly from the host vessel, the distal end being angled with respect to the base end, and an ammunition housing moveably fixed to the distal end of the strut member. A train control mechanism is positioned between the strut member and the ammunition housing for controlling the horizontal rotation of the ammunition housing with respect to the host vessel, and a tilt control mechanism is positioned between the strut member and the ammunition housing for controlling the vertical rotation of the ammunition housing with respect to the host vessel. A flexible boot is connected to the ammunition housing and surrounds each of the train control mechanism and the tilt control mechanism to protect the mechanisms from an underwater environment. The ammunition housing is movable both vertically and horizontally with respect to the distal end of the strut member and is spaced apart from the host vessel so as to avoid contacting the host vessel during directional movement of the ammunition housing. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The appended claims particularly point out and distinctly claim the subject matter of this invention. The various objects, advantages and novel features of this invention will be more fully apparent from a reading of the following detailed description in conjunction with the accompanying drawings in which like reference numerals refer to like parts, and in which: 
     FIG. 1 is a side plan view of a first preferred embodiment of the present invention showing a partial submarine hull having an appended pod underwater gun mount fixed thereto; 
     FIG. 2 is a cross sectional view taken along line  2 — 2  of FIG. 1 showing appended gun mount locations; 
     FIG. 3 is an expanded and partial sectional view of an appended pod gun mount according to the first preferred embodiment of the present invention; 
     FIG. 4 is a detailed view of the appended pod underwater gun mount according to the first preferred embodiment of the present invention; 
     FIG. 5 is a top plan view illustrating a comprehensive planar field of fire for a pair of appended pod underwater gun mounts according to the present invention; 
     FIG. 6 is a side plan view illustrating a comprehensive vertical field of fire for an appended pod underwater gun mount according to the present invention; 
     FIG. 7 is a top plan view illustrating a further appended pod underwater gun mount location and related field of fire according to the present invention; 
     FIG. 8 is a typical surface ship implementation for a deployed appended pod underwater gun mount according to a second preferred embodiment of the present invention; 
     FIG. 9 is a top plan view illustrating a field of gunfire achievable by a pair of appended pod underwater guns according to the embodiment shown in FIG. 8; 
     FIG. 10 illustrates two applications of the appended pod underwater mount according to the first preferred embodiment of the present invention; and 
     FIG. 11 diagrammatically illustrates system integration and operation of the appended pod underwater mount according to the present invention. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     In general, the present invention is directed to the mounting and control of an underwater gun so as to be able to engage and destroy attacking torpedoes. Other applications, including the use of the concept as a launcher for submarine anti-aircraft ordnance, are intended. 
     Referring first to FIGS. 1 through 4, primary features of a first preferred embodiment of the subject invention are shown. 
     FIG. 1 is a side plan view of a portion of a submarine hull  10  having a fore end  12  (not entirely shown) and an aft end  14 . A rudder  16  is vertically mounted with respect to an upright orientation of the submarine and adjacent the aft end  14  of the submarine hull  10 , and a screw  18  or other known propulsion system is mounted at the aft end  14  of the submarine hull  10  behind the rudder  16 . Stern planes  20  are horizontally mounted with respect to an upright orientation of the submarine and such that the stern planes  20  are perpendicular to the rudder  16 . 
     At least one appended pod underwater gun mount  22 , encompassing the subject matter of the present invention, is mounted to the submarine hull  10  in a position with respect thereto as shown. The appended pod underwater gun mount  22  includes a fore end  23   a  and aft end  23   b  corresponding to the fore and aft ends of the submarine hull  10 . 
     FIG. 2 is a cross sectional view taken along lines  2 — 2  of FIG.  1  and showing a stern view of the submarine hull  10  with two appended underwater gun mounts  22  mounted thereto. 
     More specifically, in FIG. 2, the stern view of the submarine hull  10  shows the location of two appended pod gun mounts  22  located symmetrically at a radial distance from a centerline  24  of the ship, and substantially greater than the radius of the hull  10 . The aft ends  22   b  of the pod mounts  22  thereby can be directed down as well as up and outwards without interference from the ship&#39;s hull  10 . At least one gun  26  (described in further detail below) is located along a longitudinal axis of each pod  22 , and will be capable of firing through a quadrant of space between rudders  16  and the stern planes  20 , and thus the critical zone of danger from attacking torpedoes, astern of the submarine, can be defended with a comprehensive field of gunfire. 
     Turning now to FIG. 3, there is shown an enlarged and partial cross-sectional view of an appended pod underwater gun mount  22  and major features thereof for connection to the hull  10  of the submarine. FIG. 4 is a side schematic view further illustrating the components of the appended pod underwater gun mount  22 . The appended pod underwater gun mount  22  is generally cylindrical in shape. The shape necessarily lends itself to a streamlined and fluid dynamic outward surface. In other applications, it is understood that the shape thereof may vary. The cylindrical appended pod gun mount  22  is controllable in train and elevation (tilt), similar to traditional gun mounts or turrets, but it is unique because of its form and the means by which it is joined to its host vessel. The size of the cylindrical pod  22  will be dependent on the specific number and types of weapons to be mounted within it. However, a representative application may be envisioned as a module about 20 feet in length and 3 feet in diameter. 
     More specifically, the pod  22  is attached to the hull  10  of a submarine as an appendage or offset structure. Rather than being attached directly to or through the hull  10  of the submarine, as a traditional turret would be, the appended pod  22  is removed several feet away from the hull  10  where it realizes the advantage of effectively being somewhat apart from the ship, while actually being integral with it and its travel. Thus, each appended pod gun mount  22  is attached to the hull  10  of a submarine or the like by a strong horn or strut  28  that extends outward and upward from the hull  10 , near the stern  14  but forward of the rudders  16  and stern planes  20 . The strut  28  is streamlined in cross section, as is the pod assembly, to minimize hydrodynamic drag. The strut  28  emerges from the hull surface  10  in a radial direction, but an outer end  30  thereof is bent upward so that a train control mechanism  32  will operate to turn the pod  22  in a horizontal plane and a tilt control mechanism  40  will operate to turn the pod  22  about a vertical plane when the ship is level. That is, a train axis  34  is at or nearly vertical and a tilt axis  36  is horizontal when the submarine is trimmed for operation at any constant depth. The horizontal motion given by this mechanism is identified as “train” in the language of naval gun mounts and turrets, and therefore is used here for consistency of terminology. On a submarine, a distance between outboard sides of the two symmetrical appended pod gun mounts  22  is kept slightly less than the beam of the ship at that location, so as to avoid interference with any object that is alongside of the vessel when in port. 
     The cylindrical pod  22  and its supporting tilt assembly rest on a bearing surface  38  where there is a motor or similar mechanism associated with the pod train control mechanism  32 . The tilt assembly including the tilt control mechanism  40  will direct the entire appended pod gun mount  22  to be rotated clockwise or counterclockwise (in FIG. 4) in accordance with remote control signals from within the host vessel. 
     The pod train control mechanism  32  is positioned below the bearing surface  38 . The amount of train may be limited by a particular application, in order to minimize the flow resistance presented by the side of the pod  22  that faces forward when trained off centerline. For a torpedo defense application, an angle of 30 degrees clockwise or counterclockwise is likely to be adequate. In all applications, it is intended that the pod mounts  22  be stabilized by fire control orders that compensate for ship motion such as roll and pitch. 
     Further, a flexible boot  42  surrounds the entirety of the tilt axis  36 , the pod tilt control mechanism  40  and the pod train control mechanism  32 . The flexible boot  42  or collar encloses the space between the pod  22  and the tilt assembly  40  to form a streamlined outer configuration. The space inside the flexible boot  42  or collar may be pressurized or free flooding to maintain its flexibility at any depth. 
     Referring further to the detail shown in FIG. 4 the appended pod  22  particularly includes forward  44  and aft  46  facing gun barrels, and at least one ammunition magazine  48 , within a cylindrical enclosure, tapered at each end to a streamlined, spindle shape. 
     FIGS. 5 and 6 illustrate the advantage provided by the appended pod gun mounts  22  in achieving a comprehensive field of fire (denoted by dashed lines  22   a ) to engage torpedoes approaching from astern. A pair of pods  22  can be mounted so that the field of fire from each of the aft facing guns  26  or gun barrels  46  overlaps the other, and it is thereby possible to engage attacking torpedoes by converging streams of projectiles that increase the overall defensive power of the guns  26  or gun barrels  46 . That is possible because of the unique offset arrangement of the two mounts  22 . 
     A secondary area of danger from attacking torpedoes is from ahead of the targeted vessel. The threat of an impending torpedo attack may be reduced by turning towards an incoming weapon as well as away from it, because of reduced aspect. Therefore, it is desirable that an anti-torpedo gun be able to fire ahead at weapons approaching the bow, as well as astern. The present invention succeeds in realizing that goal because of the combination of the previously described offset mounting and by the unique concept of having both forward  44  and aft facing  46  gun barrels within the same pod mount  22 . 
     FIG. 7 shows that each of the pod mounts  22  located near the stern  14  of a submarine can also effect a field of fire  22   a  that is forward and to the outboard side of the ship. A narrow area directly ahead of the ship remains to be guarded, and the proposed solution is to mount a third pod  22 ′ on the centerline  24  of the forward end  12  of the submarine, directly forward of a “sail” structure  50  and substantially aligned with bow planes  52  of the vessel. Thereby, the area forward of the submarine will be completely defended as shown by the field of fire  22   b  of the third pod  22 ′. 
     A major advantage for the subject invention is that it can be applied to the defense of both surface ships and submarines. Accordingly, a typical surface ship implementation is shown in FIG.  8 . In the case of a surface ship  54 , it would not be practical to mount the pods  22  permanently and offset to the sides of the ship because they would interfere with mooring the vessel in port. Consequently, the preferred embodiment of the invention when applied to a surface installation is to mount pods  22 ″ on the ends of extender arms  72 , which function similar to the struts  28  on the submarine to hold the pods  22 ″ at some distance away from the hull  55  of the ship  54  and clear of the propellers (not shown). The extender arms are configured so as to be axially extendable and able to lift the pod mounts  22 ″ out of the water and on board the host vessel to a stowed position (indicated by dashed outline  22   c ) when not needed. In order to successfully maneuver the extender arms  72 , a pivot member  74  is mounted on a deck  76  of the ship  54  and a base end  72   a  of the extender arm  72  is connected thereto. Withdrawal of the extender arm  72  and pod  22 ″ results in a pivot of about 180 degrees to place in a stowed position  22   c  on the deck  76 . Stowage is contemplated to include a platform  78  attached to a mast  80  mounted on the deck  76  of the ship  54 . Any known method of connecting to the platform  78  is considered to be within the scope of the invention. Finally, manual or automated actuation of the extender arms  72  is achieved according to a preferred system of the vessel. 
     The field of gunfire that can be achieved by a pair of appended pod underwater guns  22 ″ for defense astern of a surface ship is shown in the top plan view of FIG. 9 (dashed lines  22   d ). Since the pods  22 ″, when deployed, will be positioned just a few feet below the surface of the water, there will be little requirement for tilt except for some downward angle. The surface problem is closer to being a two dimensional situation than the submarine case, where torpedoes may threaten from above as well as below the targeted vessel. The surface pod mount installation shown in FIG. 9 will also provide some degree of protection against torpedoes attacking from forward, but a more practical and thorough defense ahead would be realized by mounting another pair of extended pods on either side of the surface ship near the bow. The use of a single, third pod, on an extender arm (not shown) directly forward of the bow is a possible alternative, but it would be more difficult to implement because of the effect of ship pitch motion which would tend to lift the pod out of the water at times. 
     A significant advantage associated with the appended pod gun mounts  22  is that in all of the installations described, access to the mounts for arming and servicing can be done above water. While the gun mounts are designed for tactical use underwater, they are readily available in the open environment to ship crews while in port or in transit. On a submarine, they are fixed at positions well above the ship&#39;s waterline when surfaced. On a surface ship, the pod mounts are designed to be brought aboard for stowage and maintenance. While intended for underwater use, the underwater pod mounts do not have to endure the rigors of a constant underwater environment. 
     The appended pod underwater gun mount  22  was inspired by the primary need to engage torpedoes that attack a ship or submarine from astern. A torpedo encounter may take place or continue to a very short range, and it is essential that a defensive stream of gunfire can be sustained, unhindered by ship structures, as long as possible in that scenario. The appended pod mount concept enables that functionality, but it has further potential. In addition to torpedo defense, the appended pod concept can be extended to support several other useful applications. 
     FIG. 10 illustrates the use of an appended pod  22  as either an underwater gun mount or missile launcher to support submarine defense against aircraft  100  or small ships  102  at close range. Such situations may be of particular concern if a submarine is required to operate in shallow water. An appended pod mount  22 , in a position above the hull of a submarine, can be trained and elevated to point in any direction above the host vessel to deploy ordnance or other devices. The pod mount  22  can serve as a self contained magazine and launcher, with no passage requirement from within the submarine except power and remote fire control signals. Finally, the underwater pod mount  22  can be considered for use as a storage and launching mechanism for other devices deployed in the oceans. Included would be various types of countermeasures, sonobuoys, and miscellaneous objects requiring covert deployment. 
     FIG. 11 is provided to address the issues of system integration and operation. Both will be influenced by the particular application selected for the appended pod underwater gun mount  22 . A simplified system diagram is provided, showing the appended pod underwater gun mount  22  used as part of a sub-system to an existing Torpedo Defense System (TDS)  60  to provide the adjunct capability of anti-torpedo gunfire. Operator control  58  is exercised via the torpedo defense system  60 . That is, a gunfire sub-system is brought to ready status and ordered to respond to appropriate detection and classification criteria by personnel in charge of the overall torpedo defense functions. A fire control computer  62  is shown for processing sensor information  56  regarding the torpedo&#39;s position, and developing launcher and firing orders  64  that will aim and fire the weapon(s) in the most effective manner. Included in those computations would be the transfer of control from one gun to another, and the coordination of more than one gun for simultaneous engagement. In the example diagram, the appended pod underwater gun mount fire control computer  62  is shown to be separate from the torpedo defense system  60 , but its functions could easily be integrated within the TDS processors. 
     Interface signals between the fire control computer  62  and the appended pod  22  are similar to those of traditional naval weapon systems. The position and status  68  of the weapon and launcher, or appended pod  22 , are fed back continually to the fire control computer  62 , while launcher orders, including train and tilt data  66  and compensation data  70  for ship motion are transmitted to the launcher. Firing orders  64  from the fire control computer  62  determine actuation of the gun(s) in the appended pod underwater gun mount  22 . 
     Accordingly, the present invention provides a remote controlled gun mount configured as a streamlined, hydrodynamic compatible module, for use underwater. Further, the underwater gun mount defined in this disclosure is unique in that it is configured as an elongated streamlined pod, similar in shape to a torpedo or a paravane, thereby presenting minimum resistance to hydrodynamic flow when oriented in its ready-for-action position, where the gun mount longitudinal axis is held parallel to the direction of motion of the host vessel. Traditional shipboard enclosed gun mounts are typically configured as circular dome shaped structures or rotating box forms. Further, the device of the present invention enables the use of guns to direct an unobstructed line of fire at objects, underwater, closing from astern of a host vessel and the concept of mounting a fully controllable gun mount offset from the hull of the host vessel is unique. Guns located within such a mount will provide a clear line of fire towards torpedoes attacking from astern. Because of the offset mount configuration, ship screws, propulsors, control surfaces, and the ship&#39;s wake will not obstruct defensive ordnance launched in that critical direction. 
     Even further, since the preferred embodiment of this invention provides two gun mount pods near the stern of the host vessel, one on either side, it is possible to engage an attacking torpedo with converging or intersecting streams of gunfire, thereby increasing the probability of a successful engagement. The invention enables simultaneous use of two gun mounts against an advancing torpedo. 
     Because of the dual mount configuration, there is builtin redundancy that will increase the availability of the TDS to respond to a torpedo threat, despite possible system casualty or degradation. 
     The streamlined pod housing of the gun mount facilitates installation of both forward and aft firing weapons within the same enclosure. Forward facing guns mounted in appended stern pods can fire directly ahead and in an arc to the outboard side of centerline ship structures such as the submarine “sail”. On a submarine, the narrow, undefended zone directly ahead of the vessel can be eliminated by the option of mounting a third pod forward of the “sail”, which will result in protection against an incoming torpedo by the combination of as many as three underwater gun mounts (see FIG.  7 ). 
     The invention is unusual in that it is applicable to both submarines and to surface ships. In addition, the underwater gun mount pods are accessible, above the water, for servicing, when not deployed. In a submarine application, the pod mounts are fixed structures that are above the ship&#39;s hull when surfaced. In a surface ship installation, the pod mounts are configured to be withdrawn to an on-board stowed position when not required. Finally, the device is configurable as a remote controlled external mount for containment and launch of anti-air and anti-surface ordnance from submarines. As described above, a viable alternative application of the underwater pod mount is to support the deployment of gun fired projectiles or small missiles against aircraft or surface craft operating above a submerged submarine that is at shallow depth. Typical targets would be anti-submarine helicopters, or surface craft at ranges too close to be engaged with anti-ship torpedoes. The pod mount could also be used to launch countermeasures, sonobuoys, or other devices that need to be deployed underwater from a ship or submarine. 
     The final configuration of the appended pod underwater gun mount will depend upon the particular application for which it is selected. A streamlined, hydrodynamic form is specified, but the exact design of the pod to achieve maximum compatibility with a ship or submarine of a specific class is a function of engineering design associated with implementation. Also, the design of the strut or extender arm that holds it away from the host platform is subject to refinement. It is acknowledged that variations in methods, materials, and construction may be applied towards achievement of the concepts disclosed herein, while maintaining the functional qualities of the invention. 
     Accordingly, it is anticipated that the invention herein will have far reaching applications other than those of underwater or above water vehicles described, and any such modification is intended to be included herein. 
     This invention has been disclosed in terms of certain embodiments. It will be apparent that many modifications can be made to the disclosed apparatus without departing from the invention. Therefore, it is the intent of the appended claims to cover all such variations and modifications as come within the true spirit and scope of this invention.