EP1895264A1

EP1895264A1 - Torpedo

Info

Publication number: EP1895264A1
Application number: EP06425609A
Authority: EP
Inventors: Luca Corbinelli; Giovanni Calvo; Luca Frediani; Germano Pratelli
Original assignee: Whitehead Alenia Sistemi Subacquei SpA
Current assignee: Whitehead Sistemi Subacquei SpA
Priority date: 2006-09-01
Filing date: 2006-09-01
Publication date: 2008-03-05
Anticipated expiration: 2026-09-01
Also published as: EP1895264B1; DE602006004449D1; ATE418715T1

Abstract

A torpedo (1) having: a main body (2); a wire (3) having a first portion (15), which forms a coil (13) secured to the main body (2), and a second portion (16) securable to a launch tube; a connector (21); and a variable-length tubular member (24) housing the second portion (16); the tubular member (24) is connected to the main body (2) by a yieldable connection (86,87;88), and is connectable to the launch tube; the tubular member (24) increases in length when the main body (2) withdraws from the launch tube, and decreases in length when the connection (86,87;88) yields; retaining means (22) maintains the connector (21) and the tubular member (24) in a predetermined position, when a force lower than a threshold value acts on connector (21) or tubular member (24), and allows relative movement between the two with a higher force.

Description

The present invention relates to a torpedo.
Torpedoes are known comprising a main body movable in the sea to strike a target; and a guidance wire for continuous information exchange between a naval vessel, e.g. a submarine or warship, and the torpedo.
More specifically, the main body of the torpedo comprises a number of stages housing respective equipment of the torpedo, such as a propulsion system, an acoustic detection unit, and a warhead.
The main body of the torpedo also comprises a control and guidance stage connected by the guidance wire to a supporting member fixed to a launch tube of the naval vessel.
More specifically, the guidance wire comprises a first and second portion comprising first ends wound into a first and second coil respectively.
The first and second portion also comprise second ends connected to each other by an intermediate connector for inspection and maintenance of the wire.
More specifically, the connector permits optical or electric data transmission between the first and second portion.
The first coil is fixed to the control and guidance stage, and the second coil to the supporting member.
The control and guidance stage comprises a casing housing the first coil.
More specifically, the first coil is maintained in a predetermined position inside the casing by a supporting structure integral with the first coil.
The first coil is housed inside the supporting structure to define a chamber extending inside the first coil. More specifically, the chamber is bounded externally by an inner lateral surface of the first coil and by the supporting structure.
The connector is located inside a wire feed duct integral with the guidance unit.
More specifically, the feed duct extends from the chamber to the supporting member, coaxially with the first coil, and is connected fluidically to an external environment surrounding the main body.
When the torpedo is housed inside a launch tube of the naval vessel, an aft portion of the torpedo is fixed releasably inside the supporting member.
In this condition, a tubular body of variable length houses the part of the second portion interposed between the second coil and the wire feed duct.
The tubular body is secured, at opposite ends, to the supporting member and the wire feed duct, and is wound inside the supporting member to a minimum length.
More specifically, the connection between the feed duct and the tubular body is designed to yield when a predetermined threshold load is reached.
At the launch stage, the main body is flooded and pressurized so the pressure inside the launch tube equals the pressure in the area of sea surrounding the torpedo exit point.
When flooding the main body, water fills the feed duct and the chamber.
Next, the aft portion is released from the supporting member to allow the main body to leave the launch tube.
Initially, detachment of the main body and the feed duct exerts pull on the tubular body, thus unwinding the tubular body and the part of the second portion housed inside it.
As it unwinds, the tubular body and the part of the wire housed inside it undergo substantially the same elastic variations in length.
So no relative slide occurs between the tubular body and the part of the wire housed inside it.
Once extended, the tubular body stretches to its maximum length, and slides with respect to the part of the wire inside it until the pull exerted eventually severs the connection between the tubular body and the feed duct.
At this point, the tubular body contracts and slides, with respect to the part of the wire housed inside it, to an intermediate idle length between the maximum and minimum lengths.
Next, the motion of the torpedo and vessel unwind the first and second coil respectively, while the wire stretched between the first and second coil remains stationary with respect to the sea.
The Applicant has observed that, whenever a fault in the launch tube calls for depressurizing and clearing the launch tube, air flows through the chamber and the feed duct, expelling the connector.
Expulsion of the connector, in particular, damages the guidance wire adjacent to the connector.
To prevent expulsion and damage of the wire, it has been proposed to locate the connector outside the feed duct, so as to reduce the aerodynamic resistance encountered by the air flow, and so reduce the force expelling the wire.
More specifically, since known torpedoes have no members, coaxial with the first coil, suitable for housing the connector and interposed between the feed duct and the tubular body, it has been proposed to position the connector crosswise and offset with respect to the axis of the first coil.
However, since the connector is positioned eccentrically with respect to the axis of the feed duct, the weight of the connector - when transporting the torpedo and when the main body is housed inside the supporting member - produces a torque on the first coil greater than the unwinding torque of the first coil.
The connector must therefore be secured in such a position as to prevent the first coil from unwinding in the above conditions.
Moreover, the connector must be prevented from interfering with extension and contraction of the tubular body at the initial torpedo launching stage.
And finally, the connector must be allowed a certain freedom of movement to prevent shock or vibration - when transporting the main body, and when the main body is housed inside the supporting member - from damaging the wire adjacent to the connector.
It is an object of the present invention to provide a torpedo designed to meet the above requirements typically associated with known torpedoes.
According to the present invention, there is provided a torpedo, as defined in Claim 1.
A preferred, non-limiting embodiment of the present invention will be described by way of example with reference to the accompanying drawings, in which:

Figure 1 shows a side view of a torpedo in accordance with the present invention and in a first configuration;
Figure 2 shows a schematic, with parts removed for clarity, of the Figure 1 torpedo;
Figures 3 and 4 show larger-scale, axial sections of details of Figures 1 and 2;
Figure 5 shows a further detail of the Figure 1 torpedo.

Number 1 in Figure 1 indicates a torpedo substantially comprising a main body 2; and a guidance wire 3 for in-mission guidance of torpedo 1 and data exchange between main body 2 and a naval vessel, in particular a warship or submarine.
More specifically, main body 2 comprises a fore portion 4 with acoustic sensors (not shown); and an aft portion 6 housing a number of propellers 7 immersed in the sea to propel torpedo 1.
Main body 2 also comprises a central portion 8 in an intermediate position between fore portion 4 and aft portion 6.
From fore portion 4 to aft portion 6, central portion 8 houses a unit 9 containing the explosive charge; an energy storage unit 10; and a control and guidance unit 11. Central portion 8 also houses a propulsion unit 5 connected operatively to unit 9 to rotate propellers 7.
During launch training, torpedo 1 is housed inside a launch tube of a naval vessel, e.g. a warship or submarine.
More specifically, aft portion 6 (as shown in Figure 1) is housed inside and connected to a hollow member 12 integral with the launch tube.
More specifically, aft portion 6 is connected to member 12 by means of a number of hydraulic jaws (not shown) on member 12, which cooperate with a shank (not shown) on aft portion 6.
When launching torpedo 1, the hydraulic jaws release the shank to allow aft portion 6 to leave member 12 and the launch tube.
Wire 3 comprises a first portion 15, and a second portion 16 (Figures 2, 3, 4, 5).
More specifically, portion 15 and portion 16 have respective ends 17, 18 fixed to guidance unit 11 and supporting member 12 respectively; and respective ends 19, 20 opposite ends 17, 18 and connected to each other by a connector 21 (Figures 4, 5) housed inside member 12.
With reference to Figure 5, connector 21 comprises a first connecting member (not shown in Figures 4 and 5) housing end 19 of portion 15; and a second connecting member (not shown in Figures 4 and 5) complementary in shape to the first connecting member and housing end 20 of portion 16.
The connecting members are connected to maintain optical connection of end 20 of portion 16 and end 19 of portion 15.
End 17 of portion 15 is wound into a hollow, cylindrical first coil 13 (Figures 2, 3) extending along an axis A and fixed inside guidance unit 11.
As shown in Figures 3 and 4, from end 17 to end 19, portion 15 is unwound off first coil 13 inside guidance unit 11, is fed along a tube 25 having a mouth 27 inside guidance unit 11 and a mouth 28 inside member 12 when aft portion 6 is housed inside member 12, and is finally fed through a fitting 26 (only shown in Figure 4) by which the part of portion 15 adjacent to end 19 is positioned crosswise and offset with respect to axis A.
End 18 of portion 16 is wound into a hollow second coil 14 (Figures 2 and 4) fixed to member 12.
From end 18 to end 20, portion 16 is unwound off second coil 14, and is housed inside a corrugated protective duct 23 and a variable-length tubular body 24, the function of which is described below.
With reference to Figure 3, guidance unit 11 substantially comprises a casing 30 extending symmetrically with respect to axis A and housing first coil 13.
More specifically, first coil 13 is maintained in a predetermined position inside casing 30 by a supporting structure 31 integral with first coil 13.
Casing 30 is housed inside a compartment bounded by an inner surface of a wall 95 (shown only partly in Figure 3) of main body 2.
Casing 30 comprises two opposite, axial end walls 32, 33 extending crosswise to axis A.
Casing 30 also comprises an annular wall 34 extending between walls 32, 33.
Structure 31 comprises two axially spaced, annular flanges 35, 36 perpendicular to axis A; and a tubular cover 37 housing flanges 35, 36.
More specifically, flange 35 comprises an outer radial end portion 38 cooperating with an axial end wall 39 of cover 37.
Similarly, flange 36 comprises an outer radial end portion 40 cooperating with an axial end wall 41, opposite wall 39, of cover 37.
At opposite axial ends, structure 31 also comprises a pin 42, of axis A, for fixing flange 35 to wall 32; and a member 50, of axis A, for fixing flange 36 to wall 33.
More specifically, pin 42 has a first axial end 43 fixed to a radially inner portion 44 of flange 35; and a second end 45, axially opposite end 43, fixed to wall 32.
Very briefly, pin 42 comprises a first member fixed to wall 32 and partly housed inside a second member fixed to flange 35.
Member 50 comprises an axial end 46 fixed to a radially inner portion 47 of flange 36; and an axial end 48 opposite end 46 and fixed to wall 33.
Member 50 defines internally a conduit 49, of axis A, decreasing radially in size from end 46 to end 48.
More specifically, tube 25 is fitted through end 48, and conduit 49 is engaged by mouth 27 of tube 25.
Portion 15 of wire 3 is wound into first coil 13 so that the first coil is bounded by two annular, axial end surfaces 51; by an outer lateral surface 52; and by an inner lateral surface 53.
More specifically, lateral surface 53 defines a hole 54 coaxial with first coil 13.
More specifically, hole 54 has opposite axial ends 55, 56.
One of surfaces 51 cooperates with flange 35, and the other surface 51 cooperates with flange 36.
First coil 13 is positioned inside casing 30 so that lateral surface 52 faces cover 37.
More specifically, the first coil is positioned inside casing 30 so that end 55 of hole 54 is engaged by end 43 of pin 42, and end 56 of hole 54 cooperates with end 46 of member 50.
A cylindrical chamber 57, of axis A, is thus defined inside first coil 13. More specifically, chamber 57 is bounded at opposite axial ends by end 43 of pin 42 and by end 46 of member 50, and is bounded radially by lateral surface 53 of first coil 13.
End 56 of hole 54 faces the inside of conduit 49 to fluidically connect chamber 57 and tube 25 by conduit 49.
An annular layer 60 of shock-absorbing material is interposed radially between cover 37 and lateral surface 52.
Structure 31 and casing 30 also define an annular chamber 70 coaxially surrounding first coil 13.
More specifically, chamber 70 comprises a first axial end defined by a portion 72; and a second axial end opposite the first and defined by a portion 73.
Chamber 70 also comprises a portion 71 extending between portions 72, 73.
Portion 72 is bounded by flange 35 and wall 32, partly surrounds pin 42, and extends substantially radially with respect to axis A.
Portion 73 is bounded by flange 36 and wall 33, partly surrounds member 50, and extends substantially radially with respect to axis A.
Portion 71 extends axially, and is defined between cover 37 and wall 34 of casing 30.
As explained below, chambers 57, 70 and tube 25 are connected fluidically to the outside environment.
Consequently, when main body 2 is housed inside member 12, tube 25 and chambers 57, 70 are at least partly filled with air.
Tube 25 and chambers 57, 70 are also at least partly filled with water when flooding the launch tube and when main body 2 is moving.
Pin 42 houses fluidic connecting means 61 interposed between chambers 57, 70 to allow a predetermined amount of water and air to circulate between, and so balance the pressures inside, chambers 57, 70.
Fluidic connecting means 61 are not described in detail, by not being essential to a clear understanding of the present invention.
A conduit 58 (Figure 3), parallel to and eccentric with respect to axis A, extends through flange 35 and a portion 59, interposed between ends 43, 45, of pin 42.
Conduit 58 is defined by a first through hole formed in portion 59, and by a second through hole formed in flange 35. The first and second hole are contiguous, and extend along the same axis parallel to and at a distance from axis A.
Conduit 58 allows all the air in chamber 57 to flow into chamber 70 when flooding the launch tube.
Conduit 58 is sized to avoid interfering with the unwinding of first coil 13.
Unit 11 also comprises a conduit 29 fluidically connecting chamber 70 to an environment outside main body 2, i.e. the sea.
Member 12 (Figures 1, 2, 4) is only described below as required for a clear understanding of the present invention.
Very briefly, member 12 comprises an axially symmetrical casing 75 (Figures 2, 4) open at the fore end to house aft portion 6 of main body 2, and closed at the aft end by a wall 76 (shown in Figure 2).
More specifically, when aft portion 6 is housed inside member 12, the axis of symmetry of casing 75 is coincident with axis A.
With reference to Figure 4, casing 75 houses a supporting structure 77 fixed to casing 75 and cooperating with second coil 14 to maintain it in a predetermined position inside casing 75; and an annular wall 78 surrounding structure 77.
Second coil 14 is similar to first coil 13 and therefore not described in detail.
Structure 77 comprises two axially opposite flanges 79, 80 cooperating with respective axial end surfaces of second coil 14; and a cover 81 interposed axially between flanges 79 and 80 and cooperating with an outer lateral surface of second coil 14.
Structure 77 is bounded at the aft end by a member 82, of axis A, cooperating with flange 80. More specifically, member 82 defines, coaxially, a conduit 83 for threading through portion 16 and which cooperates with flange 80.
Second coil 14 is positioned inside structure 77 so that a cylindrical hole 84 of the coil is coaxial with axis A, and one axial end of hole 84 faces conduit 83.
Wall 78 and casing 75 define, radially, an annular compartment 74 housing tubular body 24.
Corrugated duct 23 is fixed at one end to member 82, and at the opposite end to tubular body 24.
Tubular body 24 has a mouth 101 facing the inside of corrugated duct 23, and is secured at mouth 101 to a member 100 fixed inside member 12.
As described in detail below, tubular body 24 is secured in yielding manner to tube 25.
Tubular body 24 is a flexible corrugated tube made of metal and comprising two numbers of turns (not shown) wound into a dual coil about a longitudinal axis of tubular body 24.
Each turn is made axially slack with respect to the adjacent turns in the same number, so as to slide with respect to the adjacent turns within a given limit depending on the manufacturing process of tubular body 24.
When compressed, tubular body 24 assumes a minimum-length configuration, in which the turns are packed together.
When main body 2 of torpedo 1 is housed inside the launch tube, tubular body 24 is wound inside compartment 74 and in the minimum-length configuration.
When pulled, the turns of tubular body 24 slide with respect to one another until tubular body 24 assumes a maximum-length configuration, in which each turn is separated from the adjacent turns.
By virtue of the turns being able to slide with respect to one another, tubular body 24, when pulled, stretches more than a portion R of portion 16 housed inside tubular body 24.
Wire 3, in fact, can only extend elastically, whereas tubular body 24 can extend anelastically, by virtue of the turns sliding with respect to one another.
Tubular body 24 is housed, in the minimum-length configuration, inside compartment 74 when main body 2 of torpedo 1 is housed inside the launch tube.
As shown in Figure 4, in the above condition, tubular body 24 is wound into a number of layers 91 (only one indicated in Figure 4) superimposed radially to form a number of radial columns 92 (only one indicated in Figure 4).
Columns 92 of layers 91 are located side by side inside compartment 74.
Connector 21 advantageously extends crosswise with respect to axis A, and torpedo 1 comprises retaining means 22 (Figures 4 and 5) acting between connector 21 and tubular body 24. Retaining means 22 maintain connector 21 and tubular body 24 in a predetermined relative position when a force below a given threshold value acts on connector 21 or tubular body 24, and permit relative movement between connector 21 and tubular body 24 when a force greater than the threshold value acts on connector 21 or tubular body 24.
More specifically, torpedo 1 comprises a shell 62 (Figures 4, 5) surrounding connector 21 when aft portion 6 is housed inside member 12.
Shell 62 comprises two half-shells 63 (only one shown) connected to each other by screws.
One of half-shells 63 is fitted with a fixed magnet 64, which cooperates with a bush 65 fixed to one end 66 - located at end 20 of portion 16 - of connector 21.
More specifically, bush 65 is glued to end 66 and made of martensitic steel.
Magnet 64 is designed to exert a predetermined force of attraction on bush 65 to retain connector 21, and therefore wire 3, in a predetermined position with respect to tubular body 24 when torpedo 1 is being transported, or when aft portion 6 is housed inside member 12.
Magnet 64 exerts on bush 65 a force directed predominantly in a direction D (Figure 5) in which wire 3 extends inside shell 62.
As such, connector 21 and wire 3 are allowed to move with respect to tubular body 24 in the presence of forces crosswise to direction D and produced by shock and vibration of main body 2.
Shell 62 defines a seat 67 (Figures 4, 5) engaged by an end mouth 69 (Figures 2, 4) of tubular body 24 at the opposite end to mouth 101.
Shell 62 also defines a seat 68 located at the opposite end to seat 67 and engaged by a first mouth of fitting 26 located at the opposite end to mouth 28 of tube 25.
Fitting 26 also has a mouth 89 located at the opposite end to the first mouth and housed weakly inside mouth 28 of tube 25.
Shell 62 also comprises a number of slits 85 (only one shown in Figures 4 and 5) to let water and air into shell 62 and then into fitting 26, tube 25, and chambers 57, 70.
Shell 62 also comprises two portions 86 (only one shown in Figures 4, 5) projecting from shell 62 towards tube 25 and located on opposite sides of direction D.
Each portion 86 is connected to a respective projection 87 (only one shown in Figure 4) projecting aft from tube 25 at the mouth 28 end.
Portions 86 and respective projections 87 are connected by connecting means 88 (only shown schematically in Figures 4, 5), e.g. calibrated screws, which yield under a given load.
As such, when portions 86 are stressed by projections 87 beyond the given load, connecting means 88 yield to allow tube 25 to withdraw from shell 62 and from tubular body 24, which is integral with shell 62.
With reference to Figure 2, unit 11 also comprises a converter 93, which receives the electromagnetic signal supplied by first coil 13, and supplies an electric signal compatible with the equipment of torpedo 1, or vice versa.
Member 12 comprises a converter 94, which receives the electric signals supplied by the naval vessel, and supplies them to second coil 14, or vice versa.
In actual use, torpedo 1 is transported inside the naval vessel and positioned in a configuration (Figures 1, 3, 4) in which main body 2 is fixed inside the launch tube of the naval vessel.
In the course of the above operations, tubular body 24 is in the minimum-length configuration and wound completely inside compartment 74 of member 12.
Connector 21, as shown in Figure 4, is housed inside shell 62 and located outside tubular body 24.
Magnet 64 exerts on bush 65 a force directed substantially in direction D to lock connector 21 and wire 3 in a predetermined position.
Connector 21 being locked in the predetermined position, first coil 13 is prevented from being unwound by the weight of connector 21.
Magnet 64 allows connector 21 to move crosswise to direction D to compensate for any shock or vibration of main body 2.
When main body 2 is fixed to the launch tube, aft portion 6 is housed inside member 12 and the hydraulic jaws on member 12 cooperate with the shank on main body 2.
To launch torpedo 1, the launch tube is first flooded to bring the pressure inside the launch tube to the same pressure as the sea at the launch depth of torpedo 1.
Unit 10 is then activated, and main body 2 leaves the launch tube.
More specifically, guidance unit 11 and tube 25 withdraw from member 12, which remains fixed inside the launch tube.
Initially, by means of connecting means 88 and shell 62, withdrawal of tube 25 causes tubular body 24 and portion R inside tubular body 24 to unwind.
At this initial stage, tubular body 24 and portion R of portion 16 undergo comparable stretch, so there is substantially no relative slide between tubular body 24 and portion R of portion 16.
Moreover, connecting means 88 are substantially unstressed, by virtue of the unwinding of tubular body 24 allowing shell 62 and portions 86 to follow projections 87 of tube 25.
Tubular body 24 also prevents portion 16 of wire 3 from contacting and being damaged by propellers 7.
Once tubular body 24 is extended, withdrawal of main body 2 brings tubular body 24 anelastistically into the maximum-length configuration, whereas portion R of wire 3 is only stretched elastically.
Relative slide is thus produced between tubular body 24 and portion R, during which, mouth 69 moves with respect to connector 21 towards tube 25 into a position in which connector 21 is housed inside tubular body 24 and adjacent to mouth 69.
Tubular body 24 and shell 62 being integral with each other, shell 62 slides with respect to connector 21 towards tube 25.
The force exerted by tubular body 24 on shell 62 is greater than the threshold value, and so overcomes the force exerted by magnet 64 on bush 65.
Once the maximum-length configuration is assumed, tubular body 24 can no longer follow withdrawal of tube 25 from member 12.
Connecting means 88 are therefore stressed, by virtue of projections 87, integral with tube 25, moving away from portions 86 integral with tubular body 24.
When the stress on connecting means 88 exceeds the predetermined yield load, connecting means 88 yield, thus leaving tube 25 free to withdraw from shell 62 and tubular body 24 (Figure 2).
The pull on tubular body 24 ceases suddenly, and tubular body 24 contracts to move mouth 69 towards corrugated duct 23.
Shell 62 follows tubular body 24, and also moves towards corrugated duct 23.
As tubular body 24 contracts, connector 21 remains substantially stationary and, by virtue of the relative movement between tubular body 24 and connector 21, comes out of mouth 69.
In this case too, the force exerted by tubular body 24 on shell 62 is greater than the force exerted by magnet 64 on bush 65.
Shell 62 can therefore move with respect to connector 21.
To interrupt launching of torpedo 1, e.g. due to a malfunction of the launch tube, the launch tube must be depressurized and emptied.
Since most of the air initially inside chambers 57, 70 and tube 25 has been expelled along conduit 29 into the sea at the pressurization stage, airflow inside chamber 57 and tube 25 is particularly small.
Moreover, connector 21 being located outside tube 25, the airflow encounters very little resistance, so that the portion of portion 15 housed inside tube 25 is subjected to very little stress.
The advantages of torpedo 1 according to the present invention will be clear from the foregoing description.
In particular, magnet 64 provides for maintaining connector 21 in a predetermined position when the forces acting parallel to direction D on connector 21 are below the threshold value.
The threshold value is high enough to keep connector 21 in the predetermined position when transporting torpedo 1 and when main body 2 is housed inside the launch tube.
The weight of connector 21 is thus prevented from unwinding first coil 13.
The threshold value, however, is less than the force exerted on shell 62 by extension of tubular body 24.
Consequently, when tubular body 24 is extended, shell 62 can slide with respect to connector 21 away from corrugated duct 23.
The threshold value is also lower than the force exerted on shell 62 by contraction of tubular body 24.
Consequently, when tubular body 24 contracts, shell 62 can slide with respect to connector towards corrugated duct 23.
Moreover, the force of attraction exerted by magnet 64 on bush 65 is directed substantially parallel to the direction in which wire 3 extends inside shell 62.
Consequently, bush 65 is allowed to move away from magnet 64 to allow connector 21 and the portions of portions 15, 16 adjacent to connector 21 to accompany any shock or vibration on main body 2.
Moreover, location of connector 21 outside tube 25 and inside member 12 reduces the hydrodynamic resistance of the portion of wire 3 housed inside tube 25.
Consequently, in the event any residual air inside chambers 57, 70 is expelled along tube 25 at the depressurization stage, the forces acting on wire 3 are minor, thus reducing the risk of damage to wire 3.
Clearly, changes may be made to torpedo 1 without, however, departing from the protective scope as defined in the accompanying Claims.

Claims

A torpedo (1) comprising:
- a main body (2) housed inside a launch tube of a naval vessel and detachable from said launch tube to perform a given mission;

- a guidance wire (3), in turn comprising a first portion (15), which is wound into a coil (13) extending along an axis (A) and is secured to said main body (2), and a second portion (16) securable to said launch tube;

- a connector (21) by which to transmit signals between said first portion (15) and said second portion (16); and

- a variable-length tubular member (24) at least partly housing said second portion (16) of said wire (3);
said tubular member (24) being connected to said main body (2) by a yieldable connection (86, 87; 88) designed to yield under a predetermined load, and being connectable to said launch tube;
said tubular member (24) increasing in length to move relative to said second portion (16) as said main body (2) withdraws from the launch tube;
said tubular member (24) decreasing in length to move relative to said second portion (16), when withdrawal of said main body (2) causes said yieldable connection (86, 87; 88) to yield;
characterized in that said connector (21) extends crosswise with respect to said axis (A), and by comprising retaining means (22) acting between said connector (21) and said tubular member (24);
said retaining means (22) maintaining said connector (21) and said tubular member (24) in a predetermined relative position, when a force lower than a threshold value acts on said connector (21) or said tubular member (24);
said retaining means (22) allowing relative movement between said connector (21) and said tubular member (24), when a force greater than the threshold value acts on said connector (21) or said tubular member (24).
A torpedo as claimed in Claim 1, characterized in that said retaining means (22) exert on said connector (21) a force substantially parallel to a direction (D) in which a portion (R) of said wire (3) close to said connector (21) extends.
A torpedo as claimed in Claim 1 or 2, characterized in that said retaining means (22) are magnetic.
A torpedo as claimed in Claim 3, characterized in that said retaining means (22) comprise a magnet (64) integral with one (24) of said tubular member (24) and said connector (21); and a magnetically attractable member (65) integral with the other (21) of said tubular member (24) and said connector (21).
A torpedo as claimed in Claim 4, characterized in that said magnetically attractable member (65) is fixed to said connector (21).
A torpedo as claimed in Claim 5, characterized in that said magnetically attractable member (65) is glued to said connector (21).
A torpedo as claimed in any one of Claims 4 to 6, characterized in that said magnetically attractable member (65) is made of martensitic steel.
A torpedo as claimed in any one of Claims 4 to 7, characterized in that said magnet (64) is fitted to a member (62); said member (62) being fixed to said tubular member (24), and being secured to said main body (2) to yield under said predetermined load.