GB2251220A - A sea mine - Google Patents

Abstract

A sea mine (1) for detecting and approaching a target object (7) very rapidly by means of self-propulsion over fairly long approach paths. The sea mine (1) has an elongated flow body, behind the tail (17) of which is a propellant charge (9) which deflagrates very rapidly to produce a combustion-gas bubble (15) in the water (11) to accelerate the sea mine (1) in a directionally stable projectile like manner in the longitudinal direction (3/8) within a closed cavitation bubble (19). A sustainer (16) can be provided, to sustain propulsion after acceleration by the propellant charge (9). The mine may be propelled out of the water to attack an aerial target. <IMAGE>

Description

A SEA MINE The invention relates to a sea mine having means for deteetd ng a target object.

To attack floating target objects it is known to lay in the water mobile or ground mines which are equipped with target locating devices in order to detonate the explosive charges as a function of the proximity of a target object.

What is disadvantageous in the case of conventional sea mines is the comparatively unfavourable cost/effect ratio, particularly in view of the possibilities of deliberate protection of watercraft against conventional mine effects and the possibilities of mine clearance to ensure a course route through mine fields; the only limitedly possible attacking of non-conventional sea targets, such as for example air-cushion craft, is furthermore disadvantageous.

One could indeed consider reducing the possibilities of clearance and other defence against mines by not laying mine fields in the region of presumed course paths; instead, far aside from presumed course routes, individual mines, which are thus difficult to discover, are launched which, after location acquisition of a target object, then move, comparable to a torpedo, towards the target object that is to be attacked.What is problematical with reference to the effectiveness to-be striven for is the only comparatively slight speed, even with considerable expenditure in drive-technology respects, of explosive bodies moving like a torpedo through the water; from which there arises, more particularly in the case of rapidly travelling target objects, even in the event of target-homing which provides a lead-laying course (the so-called squinting dog course), an approach path which swings out widely, so that the target object has good prospects for timely detection of the approaching explosive body and thus to put into effect diversionary or defensive measures.

The problem underlying the present invention is how to enable these disadvantages to be reduced or avoided.

According to the present invention there is provided a sea mine which has an explosively deflagrating or a like semi-explosive propellant charge, whereby to provide a considerably more rapid approach to the target object, as compared with the possibilities of conventional torpedo drive methods in the water. The sea mine consequently lessens the possibilities of the target object to detect and take defensive action against the attack by a sea mine, which is thus considerably more effective. The propellant charge and the shape of the sea mine are preferably arranged to accelerate the mine to a velocity at which movement of the mine is stabilised by cavitation.

The invention also provides a sea mine with a location device for acquiring a target object, characterised in that it has a casing, in the form of an elongated flow body having a longitudinal axis, comprising a head, shaped to give rise to a cavitation bell, and a cylindrical body behind the head; in that the location device is orientated in the direction of the longitudinal axis; and in that arranged at the rear of or behind the body is a container having a characteristic of a sabot, in which there is a propellant charge comprising material which can deflagrate explosively for producing a powerful development of combustion gas at the rear of the mine; and intrinsic to this solution of the problem is the realisation that, without great expenditure on apparatus, it is possible to impart to a mine, having appropriate flow geometry in the water, such a high initial velocity that without delay a stable cavitation bubble builds up around the sea mine, in which the sea mine, physically isolated relative to the effects of the surrounding water, is propelled in a directionally stable manner in the direction of the initial acceleration. This initial and propulsion acceleration results, in this respect, from the force of reaction of the formation and expansion of a combustion-gas bubble relative to the comparatively inert mass of the surrounding water.Thus it is made possible for the sea mine to reach even very fast sea targets, for example along a direct path in the manner of a direct shot, and to penetrate or explode in or against the target or to explode in the immediate vicinity of the target.

The sea mine can be designed as a sinking body which, after being launched, sinks down onto the sea bed and remains there in a predeterminable attitude, inclination or spatial orientation or direction, for example supported relative to the sea bed, until, triggered by way of the location device, the propellant charge is detonated. The sea mine can, however, also be designed as a suspended body which, after being launched, sinks down as far as a constructionally predetermined depth of water and remains suspended there, in which respect, by appropriate arrangement of buoyancy volumes, a specific inclination, attitude or spatial direction or orientation in the water can be predetermined.More especially in the case of not too great a depth of suspension of the sea mine, also a spatial attitude or orientation parallel to the surface of the water can be provided for, whereby the range of action of the sea mine against surface vessels is enlarged. The sea mine is usable even against objects which stand not too high above the surface of the water and which can be located from the sea mine.

In this case it is particularly expedient to dimension the propellant-charge drive only for the high initial acceleration after the acquisition of an object to be attacked and after that then to start up an additionally provided propulsion sustainer which ensures the propulsion over the remaining path of travel, and possibly shooting out of the water.

Additional further developments and alternatives as well as further features and advantages of the invention, some of which are mentioned in the appended claims, will become apparent from the following description of an exemplified embodiment and example of application of a sea mine in accordance with the invention, with reference to the accompanying diagrammatic drawing which is simplified and restricted to show the sea mine being accelerated in the direction of a target object.

The sea mine 1 shown in the drawing and configurated approximately similar to a torpedo or similar to a rocket, has a casing 2 in the form of an elongated flow body which is rotationally-symmetrical about the longitudinal axis. The casing has a head 4, for giving rise to a cavitation bell 18, and a cylindrical body 5, and, as indicated in the drawing, transitional regions of adapted geometry may be provided between the head and body 5.In casing 2 there is disposed a detonation triggering device (not shown in the drawing) for payload explosive enclosed in the body 5 Detecting means, comprising a location device 6 is orientated in or on the casing 2, with reference to the longitudinal axis 3 of the mine, to serve, in a manner known as such, by means of active (reflection procedure) or passive (listening procedure) water-borne sound location techniques, for the acquisition of the moment when a target object 7, for example a surface vessel, a submarine or a flying body above the surface 14 of the water, is present in or crosses the direction of the longitudinal axis 3 of the mine to the front of the mine and thus the propulsion direction 8 of the mine.

At this moment, triggered by way of the location device 6, a propellant charge 9, at the rear of the casing 2, is detonated, which charge 9 consists of a material which deflagrates explosively to detonate or burn, possibly as a result of appropriate material additives, to produce a rapid and powerful development of combustion gas.For this, arranged behind the body 5 of the mine is a rotationally-symmetrical pressure-dish container 12, which until detonation or ignition of the charge 9 is closed rearwardly with regard to the surrounding water 11, and which the deflagrating charge tears or bursts open rearwardly The diameter of the container 12 corresponds, in the connection region to the body 5, approximately to the diameter of the latter whilst the diameter preferably increases somewhat in a funnel-shaped manner contrary to the propulsion direction 8 of the mine, in order to serve in a sabot like manner with respect to the combustion gases as hereinafter mentioned. The charging level of this container 12 with material of the propellant charge 9 is predeterminable by inserts, for example a base plate 13.

The orientation of the longitudinal axis 3 and thus of the later propulsion direction 8 in space of the sea mine 1 in the water 11, in other words an orientation for example perpendicularly or, as shown in the drawing, inclined - with regard to the surface 14 of the water, can be predetermined by appropriately arranged weight distribution and appropriate buoyancy characteristics of the body 5 of the mine in the case of a sea mine 1 suspended in the water 11.

When the location device 6 has ascertained the said criterion for the activation, e.g. detonation or ignition, of the propellant charge 9, there arises, as a result of the explosively proceeding combustion or detonation, behind the rearwardly torn-open sabot container 12 a combustion-gas bubble 15 the volume expansion of which, by reason of the inertia of the surrounding mass of the water 11 which is incompressible against this sudden stressing, brings about a force of reaction which causes a force component to act by way of the bubble 15 against the tail of the mine, e.g.

via the container 12, and thus exerts a force at the rear side 10 of the mine to accelerate the mine in its propulsion direction 8.

It has become apparent that, by this simple arrangement of a pressure-resistant propellant-charge container 12 behind the tail 17 of the sea mine 1, this experiences, without the requirement of a pressure tube (as in the case of the firing of a projectile from the barrel of a weapon), a directed and extremely high initial acceleration, approximated to the conditions of a projectile launching from a weapon barrel, in the specific stable direction 8.

From the commencement of motion with such high initial acceleration there results, in the region of the head 4 of the mine, the formation of a cavitation bell 18. This cavitation continues, by reason of the extremely high acceleration of the sea mine 1, along the body 5 thereof; so that without delay a continuous ellipsoid-shaped closed cavitation bubble 19 forms along the whole of the sea mine 1, which coalesces in the vicinity of the rear side 10 of the mine with the gas bubble 15 and is substantially free of water 11.

Through the production of a specific cavitation bubble 19 with respect to the mine geometry, the movement of the sea mine towards the located target object 7 ensues in a directionally stable manner. The rearwardly funnel-shaped expansion of the propellantcharge container 12 makes an additional contribution to the directional stabilisation of the moving sea mine 1 relative to the cavitation bubble 19.

In the interests of a rapid build-up of this closed cavitation bubble 19, which stabilises the propulsion direction, additional constructional measures may be taken which, by reason of improving the flow geometry of the mine, lead to a strengthened cavitation tendency. In the diagrammatic sketch of the drawing, such measures are schematically indicated by the geometry of the transitional region 20 between head 4 and body 5.Additionally, there can be formed in the sea mine 1 flow channels 21 which conduct small amounts of combustion gases from the region of the propellant-charge container 12 into the vicinity of the head 4 of the mine and allow them to emerge there as small bubbles to serve as cavitation nucleii, to promote the buld-up of the cavitation bell 18 and its propogation to the closed cavitation bubble 19, for improving the stability of movement of the mine in the propulsion direction 8.

Operational tests have shown that already with current pyrotechnical materials, for example, materials having a potassium perchlorate basis, and other very rapidly deflagrating propellantcharge materials, for example materials having a nitrocellulose or nitroglycerine basis, as propellant charge 9, the weight of the sea mine 1 as a whole can constitute up to 50 times the weight of the propellant charge 9 required to set the sea mine 1 in motion, out of its rest position in the water 11, with an acceleration of the order of magnitude of or approaching that of accelerations found upon launching projectiles from a weapon barrel, and thereby to build up rapidly the stable cavitation bubble 19 for the directionally stable propulsion.In this respect, the acceleration/ time behaviour can be predetermined by way of the size of the initial rearward opening of the propellant-charge container 12 in comparison with the diameter of the body 5 of the mine and by way of the charging level of the container 12 with propellant charge 9, with particular respect to the initial distance, to be expected, to the target object 7 and the cavitation-crucial geometry of the casing 2 of the sea mine.

The propellant charge is preferably of a material which burns, detonates or deflagrates at a speed substantially within the range of 100 metres per second to 2000 metres per second.

In the diagrammatic sketch drawing it is taken into account that it can be expedient to supplement the propellant-charge drive of the sea mine 1 by a propulsion sustainer 16 which is installed in the tail 17 of the body 5 of the sea mine, which sustainer may be of a form which would not, by itself, provide the necessary initial acceleration of the sea mine 1 for directionally stable propulsion in the water 11, so that the dimensions of the sustainer may be limited to take into account the restricting condition that the space for the useful or payload charge, in the body 5 of predetermined dimensions, must not be too severely restricted by such a driving system 16.

After location of a target 7 to be attacked with the sea mine 1, the rapid initial acceleration thus ensues by detonating the propellant charge 9, whereupon the cruising velocity reached after the deflagration of the propellant charge 9 is maintained or even further increased by firing the sustainer 16. This is thus of particular interest in the case of long paths of travel of the sea mine 1, as for example substantially parallel to the surface 14 of the water, or when attacking target objects above the surface 14 of the water (not taken into account in the drawing).

Claims (13)

1. A sea mine comprising means for detecting a target object and means for propelling the mine towards the target object wherein the mine is of elongate form and has a longitudinal axis; wherein the means for detecting a target object is responsive to the presence of a target object before the mine in the direction of the longitudinal axis; and wherein the means for propelling the mine comprises a propellant charge which deflagrates or detonates rapidly or explosively or combusts at a semi-explosive or explosive like rate to eject gaseous deflagration, explosion or combustion products at the rear of the mine.

2. A sea mine with a location device for acquiring a target object characterised in that it has a casing, in the form of an elongated flow body having a longitudinal axis, comprising a head, shaped to give rise to a cavitation bell, and a cylindrical body behind the head; in that the location device is orientated in the direction of the longitudinal axis; and in that arranged at the rear of or behind the body is a container having a characteristic of a sabot, in which there is a propellant charge comprising material which can deflagrate explosively for producing a powerful development of combustion gas at the rear of the mine.

3. A sea mine as claimed in Claim 2, characterised in that its casing has geometrical regions for promoting the occurrence of cavitation pheonomena.

4. A sea mine as claimed in Claim 2 or 3, characterised in that the propellant charge container is designed as a rotationallysymmetrical hollow body and is fastened coaxially with the body of the mine behind the rear side thereof.

5. A sea mine as claimed in Claim 4, characterised in that the container is a pressure-resistant hollow truncated cone which has a stabilising effect upon the propulsion of the mine relative to cavitation bubble.

6. A sea mine as claimed in one of Claims 2 to 5, characterised in that the charging level of the container with propellant charge is predetermined by an insert base plate 7. A sea mine as claimed in any one of the preceding claims, characterised in that a sustainer to propel the mine is arranged, in or at the rear of the body, in front of the propellant-charge container.

8. A sea mine as claimed in any one of the preceding claims, characterised in that its propellant charge consists of a rapidly deflagrating explosive material with a gas producing, gas promoting or fume-forming additive material.

9. A sea mine as claimed in any one of the preceding claims, characterised in that it is constructed and arranged to achieve a suspended state, in a predetermined attitude, inclination or spatial direction, when in the water.

10. A sea mine as claimed in any one of the preceding claims! characterised in that it is equipped with flow channels for cavitation nucleus formation as a result of the ejection of small gas bubbles.

11. A sea mine as claimed in any preceding claim in which the propellant charge is of a material which burns, detonates or deflagrates at a speed substantially within the range of 100 metres per second to 2000 metres per second.

12. A sea mine substantially as hereinbefore described with reference to the accompanying drawing.

Amendments to the claims have been filed as follows 1. A sea mine comprising means for detecting a target object and means for propelling the mine towards the target object, wherein the mine has a body of elongate form, has a longitudinal axis and has a head shaped to promote cavitation when the mine is propelled; wherein the means for detecting a target object is reponsive to the presence of a target object before the mine in the direction of the longitudinal axis; and wherein the means for propelling the mine comprises a container containing a propellant charge which deflagrates, detonates or combusts at a sufficiently explosive rate to accelerate the mine rapidly to a velocity at which it is surrounded by a cavitation bell extending rearwards from the head.

2. A sea-mine with a location device for acquiring a target object characterised in that it has a casing, in the form of an elongated flow body having a longitudinal axis, comprising a head, shaped to give rise to a cavitation bell when the mine is propelled forwards rapidly, and a cylindrical body behind the head; in that the location device is orientated in the direction of the longitudinal axis; and in that arranged at the rear of or behind the body is a propellant charge in a container which acts in a sabot-like manner in relation to gas at the rear of the mine, produced by the propellant charge at a sufficiently explosive rate to accelerate the mine as a projectile to a velocity at which it proceeds in a directionally stable manner within the cavitation bell in the direction of initial acceleration.

3. A sea mine as claimed in Claim 1 or 2, characterised in that the propellant charge container is designed as a rotationally-symmetrical hollow body and is fastened coaxially with the- body of the mine behind the rear thereof.

4. A sea mine as claimed in Claim 3, characterised in that the container is a pressure-resistant hollow truncated cone which has a stabilising effect upon the propulsion of the mine relative to cavitation bell.

5. A sea mine as claimed in any one of Claims 1 to 4, characterised in that the charging level of the container with propellant charge is predetermined by an insert base plate.

6. A sea mine as claimed in any one of the preceding claims, characterised in that a sustainer to propel the mine after initial acceleration is arranged, in or at the rear of the body of the mine, in front of the propellant-charge container.

7. A sea mine as claimed in any preceding claim in which the propellant is of a material which burns, detonates or deflagrates at a speed substantially within the range of 100 metres per second to 2000 metres per second.

8. A sea mine, for attacking a detected target object ahead of the mine, in the form of a flow body provided with a drive, characterised in that it has a head which brings about, upon rapid travel through the water after rapid initial acceleration, a cavitation bell which surrounds the body and links to the head to form a closed cavitation bubble, in which the flow body, isolated relative to the effects of the surrounding water, progresses in a directionally stable manner in the direction of the initial acceleration, and in that the drive is in the form of a propellant which acts in the direction of initial acceleration.

9. A sea mine as claimed in Claim 8, characterised in that its drive comprises a sustainer effective after initial acceleration.

10. A sea mine as claimed in any preceding claim, characterised in that its body has geometrical regions for promoting the occurrence of cavitation phonomena.

11. A sea mine as claimed in any one of the preceding claims, characterised in that it is constructed and arranged to achieve a suspended state, in a predetermined attitude, inclination or spatial direction, when in the water.

12. A sea mine as claimed in any one of the preceding claims, characterised in that it is equipped witn internal flow channels for conveying gas to the head, to promote cavitation nucleus formation by the ejection of small gas bubbles at the head.

13. A sea mine substantially as hereinbefore described with reference to the accompanying drawing.