Torpedo propulsion system for vessels

Abstract

Torpedo propulsion unit (1) for vessels, equipped with a structure (2) for coupling to the keel (10) of a vessel hull, said structure (2) being movable, by means of appropriate actuators (3), from a position of maximum distance from the keel ( 10) to a position of maximum proximity, all intermediate positions being continuously accessible; said structure (2) comprising a pair of uprights (102) connected at one end (112) to the keel of the hull of the vessel, arranged on the longitudinal axis of the hull at a given distance from each other, and at the opposite end being provided with sliding means (122) suitable for cooperating with a portal frame (202) arranged to slide between the two uprights (102), and in which a column element (302) is provided, positioned between the uprights (212) of said portal (202), the upper end of which is equipped with slide means (322) coupled to the uprights (212) of said portal (202), and the lower end (312) of which is coupled to the fuselage (101) of said torpedo propulsion unit (1), the drive means (3) of said slide means (122, 322) being positioned on said portal (202).

Description

[0001] TORPEDO PROPULSION SYSTEM FOR VESSELS

[0002] The present invention relates to shipbuilding , and in particular to the construction of SWATH and HYSWAS hulls and the refit of traditional hull vessels , preferably catamarans , through the adoption of mobile torpedo marine propulsion systems .

[0003] They include both the means of propulsion and the means of storing propulsion energy. These torpedoes can also be equipped with hydrofoils suitable for developing the hydrodynamic lift of the vessel ; the torpedo is connected to the keel of the vessel by one or more connecting pylons , which can be fixed or retractable .

[0004] Currently, electric or hybrid nautical or naval units are built using traditional shaft lines driven by motors inside the hull or by more efficient external propellers , driven by electric motors inside the propeller nacelle , or by mechanical transmission of motion to the propellers . In this case too , the prime mover is inside the hull .

[0005] In this regard, one can consider , for example , the standard configuration of a ship with electric propulsion and a diesel generator , or external propulsion systems such as that described in EP3604117 , or hybrid configurations such as that described in WO2021234748 .

[0006] In general , energy storage , whether in liquid form (hydrocarbons or hydrogen) or in various types of batteries , is carried out inside the hull . This allows for excellent accessibility to the various components but also requires the ship to be designed and built around them or taking them into account .

[0007] Furthermore , this means that the electrification or "hybridization" of an existing unit involves having to stop the ship for several months , surveying the current propulsion configuration , designing the modification , and working on board to find useful space for the installation of new components , which is not always available . This "revamping" is therefore not always feasible , both for reasons of space and weight .

[0008] Adding batteries , electric motors , drives , and other components to a ship designed for a certain displacement can reduce the payload and may require the batteries and other loads to be distributed to balance the trim. This means further increasing the weight and complexity of the system.

[0009] In the event of maintenance , identifying and repairing the fault can take days , weeks , or even months . In the management of a fleet of passenger vehicles , for example , this time leads to a significant increase in the total cost of maintenance and / or warranty .

[0010] A possible innovative solution to the problem has been introduced with the use of a special HYSWAS hull , with a torpedo propulsion unit and integrated energy storage , as described, for example , in document WO2024047545 . The torpedo of these vessels contains both the propulsion unit and the batteries or hydrogen cylinders .

[0011] In this case , the entire product life cycle is improved : from the design of the vessel , which is simpler as it primarily involves the integration of the standardized torpedo , to construction , durability and end of life ; a life that can be longer because upgrading the propulsion system will be simpler and more cost-effective .

[0012] In developing the design behind this invention , the applicant analyzed various issues and benefits related to this configuration . These benefits and issues can also be found in the application of the propulsive torpedo solution for the revamping of existing boats or projects , such as catamarans .

[0013] In these cases , it is also essential to keep the torpedo submerged as much as possible , in order to increase its efficiency and prevent the propellers from being exposed, and to retract it as far as possible towards the deck , in order to reduce the draft and also to access the inside of the torpedo out of the water for larger sizes . This means having very large useful strokes for its movement , which cannot be achieved with single-extraction linear guides .

[0014] In the field of sailing boats , solutions such as those described in WO2018087583 have been developed for keel movement . These solutions are applicable in boats designed to have a sufficient minimum retracted length of the keel post and space inside the vessel .

[0015] In the case of the vessels mainly dealt with by the applicant , but also in the case of electrical retrofits of traditional catamarans , the minimum length of the support pylon is low and the space inside the boat is minimal . In general , the retracted support would protrude onto the deck , invalidating the winning concept of a standardized "platform" with a "free" configuration above the deck ; in the case of retrofits , the space inside the boat is unknown and varies from one case to another . The aim of the present invention is therefore to provide a torpedo propulsion system that can be easily coupled to the keel of a specially designed boat or to the keel of an existing boat , by means of a suitable coupling structure capable of varying the distance between the keel and the torpedo in a widely adjustable manner , while at the same time achieving a minimal overall size compared to the possible range of movement .

[0016] A further aim of the present invention is a torpedo propulsion system optimally designed to optimize its hydrodynamic and propulsive configuration according to the immersion conditions and speed at which it operates .

[0017] The object of the present invention is therefore a torpedo propulsion system for vessels , equipped with a structure for coupling to the keel of a vessel , said structure being movable , by means of appropriate actuators , from a position of maximum distance from the keel to a position of maximum proximity, all intermediate positions being continuously accessible ; said structure comprising a pair of uprights connected at one end to the keel of the hull of the boat , arranged on the longitudinal axis of the hull at a given distance from each other , and at the opposite end being provided with sliding means suitable for cooperating with a portal frame arranged to slide between the two uprights , and in which there is provided a column element positioned between the uprights of said portal , the upper end of which is equipped with sliding means coupled to the uprights of said portal , and the lower end of which is coupled to the body of said torpedo , the means for actuating the movement of said sliding means being positioned on the aforementioned portal . In an embodiment , said actuating means comprise a gear motor coupled to means for transmitting motion to the sliding means of the uprights and the column element . In particular , said transmission means comprise a plurality of transmitting means coupled to a transmission belt or chain for transporting and synchronizing the movement .

[0018] Preferably, said coupling structure is enclosed in a telescopic box-shaped body, formed by two or more portions of similar section , coaxial and concentric with each other .

[0019] The coupling structure in the extended configuration is approximately twice as long , from one end to the other , as the structure in the retracted configuration . The sliding means correspond to approximately one quarter of the length of the element , upright or column , to which they are associated .

[0020] In one embodiment , the coupling structure is connected to the keel of the vessel by means of two plates that are coupled together at an opening in the keel , taking the keel wall between them, said plates being provided with sealing means that interact with the edge of the keel opening , the plate facing the outside of the keel being coupled with the uprights of the support structure .

[0021] A further object of the present invention is a torpedo propulsion unit whose fuselage has a substantially elliptical section , the major axis being parallel to the horizontal plane , provided with two pairs of wings positioned along the centerline of the fuselage , respectively in the vicinity of the stern ogive and the bow ogive ; the bow ogive and the stern ogive are movable and adjustable . In particular , the bow ogive is made of semi-rigid or inflatable material . This feature allows any impacts with submerged objects to be cushioned .

[0022] In one embodiment , the bow ogive moves upward or downward by means of an adjustment system that defines its angle of trim. In particular , the bow ogive is connected to the torpedo fuselage by means of an oscillating coupling between two plates facing each other , controlled by actuators .

[0023] In one embodiment , the stern ogive comprises two portions articulated to each other by means of a spherical joint , the motor shaft being connected to the propeller drive shaft by means of a cardan joint located in said spherical joint, actuators being provided for adjusting the relative position of the two portions .

[0024] In a further embodiment , the stern ogive comprises two portions articulated to each other by means of a spherical joint , pivoted by an axis perpendicular to the horizontal plane , of which a first proximal portion is connected directly to the torpedo fuselage , and the other distal portion entirely houses the motor inside it, with means for actuating the distal portion of the stern ogive ; alternatively, these means may be located in the proximal portion of the ogive , at the spherical joint , or may be located inside the distal portion of the ogive . In the latter case , these actuating means are in a substantially watertight environment .

[0025] In another embodiment , the wings of the torpedo propulsion system are mounted on the fuselage by means of a rotating wrist system that allows both the angle of attack to be controlled and the wing to be closed during manoeuvres , in port or in areas at risk of collision . Further advantages and features of the torpedo propulsion system according to the present invention will become apparent from the following description of an embodiment thereof , by way of example and not limitation , with reference to the accompanying drawings , in which :

[0026] Figure 1 is a side elevation view of the torpedo propulsion system according to the present invention , with the coupling structure to the hull of the boat in extended configuration ;

[0027] Figure 2 is a top view of the torpedo propulsion unit of Figure 1 ;

[0028] Figure 3 is a front elevation view of the coupling structure in the extended configuration ;

[0029] Figure 4 is a front elevation view of the coupling structure in the retracted configuration ;

[0030] Figure 5 is a top view of the coupling structure ;

[0031] Figure 6 is a side elevation view of the coupling structure ;

[0032] Figure 7 is a view with longitudinal sections of a variant of the connection between the coupling structure and the keel of the boat ;

[0033] Figure 8 is an enlarged perspective detail , with sections , of the variant shown in Figure 7 ;

[0034] Figure 9 is an enlarged detail with longitudinal sections of an embodiment of the stern ogive of the torpedo propulsion unit of Figure 1 ;

[0035] Figure 10 is an enlarged detail with longitudinal sections of an embodiment of the bow ogive of the torpedo propulsion unit of Figure 1 ; Figure 11 is a longitudinal sectional view of a first variant of the stern ogive of the torpedo propulsion system;

[0036] Figure 12 is a longitudinal sectional view of a second variant of the stern ogive of the torpedo propulsion system.

[0037] Figure 1 illustrates an embodiment of the torpedo propulsion system for vessels according to the present invention ; 1 denotes the torpedo propulsion system, which comprises the fuselage 101 , provided with the bow ogive 401 and the stern ogive 501 , from which the propeller 601 protrudes . Along the sides of the fuselage , near the bow ogive 401 , there is a pair of wings 201 , only one of which is visible in the figure , while near the stern ogive 501 there is a pair of wings 301 . The torpedo propulsion unit 1 is connected to the keel 10 of a boat by means of structure 2 ; this structure 2 comprises two uprights 102 which are fixed to the keel by means of plates 112 , while at the opposite ends there are skids 122 , which cooperate with the guides 222 provided on the outward facing surface of each of the two uprights 212 of the portal 202 . The guides 222 on the inward facing surface of the portal 202 are coupled to the slides 322 provided at the upper end of the column 302 , which at the opposite end has the plate 312 connected to the fuselage 101 . The coupling structure 2 is surrounded by the telescopic box-shaped body 4 , shaped to contain the aforementioned structure ; actuation is ensured by the actuation means 3 , which will be described in more detail below . Figure 2 shows the torpedo propulsion system according to the invention in plan view from above ; identical parts are identified by the same numbers . In this figure , comparing it with Figure 1 , the substantially elliptical cross-sectional shape of the fuselage 101 can be seen , with the major axis of the ellipse substantially parallel to the horizontal plane . The wings of the torpedo propulsion system can be mounted on the fuselage by means of a rotating wrist system, not shown here , which allows both the angle of attack to be controlled and the wing to be closed during maneuvers , in port or in areas at risk of collision .

[0038] Figure 3 shows the coupling structure of the torpedo propulsion system in its extended configuration ; identical parts are marked with the same numbers . The gear motor 103 is located on the portal 202 and drives the shaft 113 , on which the gear wheel 123 is keyed on one side . This meshes with the larger diameter gear wheel 203 , which in turn drives the wheels 303 , arranged on one of the two uprights 212 of the portal 202 , connected to each other by the chain 503 , and coupled to the slides 322 of the column 302 and to the slides 122 of the uprights 102 . On the other upright 212 , the wheels 303 are driven by wheel 403 , which is coupled to the shaft 113 of the gear motor 103 by means of belt 143. The slides 122 , 322 slide on the guides 222 of the uprights 212 of the portal 202 , which are essentially rail-shaped, thanks to the sliding means 132 , 332 . The counterclockwise rotation of shaft 113 causes the slides 322 of column 302 to slide upwards and the slides 122 of uprights 102 to slide downwards , thus bringing the coupling structure from the extended configuration to the retracted configuration shown in Figure 4 , in which the same numbers correspond to the same parts . The figure shows the compactness of the coupling structure 2 , and a comparison of Figure 4 with Figure 3 shows that the overall height of the coupling structure essentially doubles from the retracted configuration to the extended configuration .

[0039] Figure 5 shows a top view of the coupling structure ; identical parts are marked with the same numbers . The figure highlights the presence of tensioner 153 of belt 143 , which connects wheel 403 to wheel 133 , which is keyed onto shaft 113 of gear motor 103. Figure 6 shows the coupling structure in side elevation ; here too , the same numbers correspond to the same parts . This figure shows the overall balance of the support structure .

[0040] Figure 7 shows a variant design for connecting the coupling structure to the keel of the boat ; the same numbers correspond to the same parts . The keel 10 has an opening 11 with sloping outer edges 12 ; two plates 104 and 204 are secured to the edge of this opening 11 , facing outwards and inwards of the boat respectively; the two plates are fixed to the keel by threaded rods 304 that pass through the plates and the keel , and the corresponding bolts 314 . The outer plate 104 has a coupling flange 114 along its peripheral edge , from which a radial flap 124 protrudes , capable of coupling with the flap 224 protruding from the coupling flange 214 of the inner plate 204 . Triangular sealing elements 404 are inserted between the flaps 124 and 224 and the inclined walls 12 of the opening 11 . The plates 112 of the uprights 102 of the coupling structure 2 are coupled to the outer plate 104 by means of fasteners 122 . The respective openings 134 , 234 are made in both plates 104 , 204 to allow the passage of the power supply and control lines of the actuating means 3 of structure 2 ; in addition , the inner plate 204 has openings 244 in correspondence with the fastening means 122 protruding from the outer plate

[0041] 104 .

[0042] Figure 8 , in which equal parts are marked with equal numbers , better clarifies the configuration of opening 11 on keel 10 and highlights how plates 104 and 204 are connected to each other and to keel 10 .

[0043] Figure 9 shows a detail of the stern ogive of the torpedo propulsion system according to the present invention . The stern ogive 501 consists of a proximal portion 511 , connected to the torpedo fuselage , not shown in the figure , and a distal portion 521 , connected to each other by a spherical joint formed by the member 531 which branches off from the proximal portion 511 and the member 541 connected to the distal portion 521 . The bellows joint 581 is arranged between the two portions . Axially to the distal portion 511 is the terminal 611 of the motor shaft 631 of the propeller 601 , not shown in the figure , which is coupled to the motor shaft 631 by means of the reduction gear 641 and the cardan joint 621 , positioned between members 531 and 541 of the spherical joint . The casing 651 of the reduction gear 641 is permanently connected to the proximal portion 511 of the stern ogive 501 . The actuator 551 is located on the proximal portion 511 in 561 and is coupled to the distal portion 521 at the opposite end 571 .

[0044] Figure 10 illustrates the bow ogive 401 of the torpedo propulsion unit according to the present invention . The torpedo fuselage 101 has a first transverse plate 111 coupled by means of the bracket 131 to the slot 171 of a second transverse plate 151 ; the actuator 141 is connected to the second plate 151 by means of the pin 181 . The bellows joint 161 is arranged between the two plates . The second plate 151 is coupled to a cylinder portion 411 in which the piston-shaped element 421 is slidably inserted, from which a truncated cone-shaped flange 451 protrudes , to which the inflatable portion 461 of the ogive 401 is hooked . The movement between the cylindrical portion 411 and the element 421 is provided by the actuator 431 , and the bellows joint 441 connects the outer surface of the cylinder portion 411 to the piston element 421 . The inflation and deflation of the inflatable portion 461 of the ogive are ensured by the ducts 471 and 481 .

[0045] Figure 11 illustrates a first embodiment of the stern ogive of the torpedo propulsion unit according to the present invention ; the ogive 701 is connected to the end of the torpedo fuselage 101 by means of its proximal portion 721 , which has spherical sector walls 731 suitable for cooperating with the spherical sector walls 741 of the distal portion 711 . The proximal portion 721 has an axial cavity 761 in the center , in which an actuator 771 is arranged, which at one end connects to the aforementioned cavity at 781 , and at the opposite end couples to 781 ’ with the interior of the axial cavity 751 formed in the distal portion 711 of the ogive 701 ; the distal portion 711 is pivoted on the axis 791 , which is integral with the proximal portion 721 . The propeller 601 is keyed onto the axis 611 which is driven by the electric motor 661 , completely contained within the distal portion 711 of the stern ogive 701 .

[0046] Figure 12 illustrates a second variant of the stern ogive of the torpedo propulsion system according to the present invention ; the same numbers correspond to the same parts . In this case , the stern ogive 801 has a proximal portion 821 with spherical sector walls 831 designed to cooperate with the spherical sector walls 841 of the distal portion 811 . Inside the distal portion , which is crossed by the axis 851 integral with the proximal portion 821 , there is a plate 871 to which two actuators 861 are connected in a swinging manner at their ends , which are coupled at their respective opposite ends to the walls of the distal portion 811 .

[0047] The operation and structure of the torpedo propulsion unit according to the present invention will become apparent from the following . The fuselage of the torpedo propulsion unit has an elliptical crosssection with the major axis parallel to the horizontal plane and is provided, substantially centrally along the longitudinal axis , with a housing for positioning the coupling structure 2 . Advantageously, it can be seen that the plate 312 of the column 302 , intended for connection to the fuselage 101 of the torpedo propulsion unit , has a width substantially equal to the overall width of the structure 2 . This feature confers considerable stability to the coupling , particularly when compared to telescopic coupling systems known in the prior art .

[0048] The coupling structure described above allows for optimal use of the available space , providing a solid, stable coupling that allows for precise control of the distance between the keel 10 and the torpedo propulsion unit 1 . The slides 122 , 322 that run on the guides 222 of the uprights 212 of the portal 202 are made in a size that, on the one hand, allows considerable stroke between the extended and retracted configurations and, on the other hand, guarantees the stability of the extended configuration ; in particular , the slides are substantially a quarter of the length of the element to which they are associated, whether this is column

[0049] 302 or uprights 102 .

[0050] The slides are driven by chain 503 , which connects them to each other at a distance that allows slides 322 to be lowered while slides 122 rise at the same time , achieving maximum extension of structure 2 . Similarly, when the gear motor 103 is operated in the opposite direction , the portal 202 rises along the uprights 102 and the column 302 rises inside the portal 202 .

[0051] The shaft 113 of the gear motor 103 is coupled to a chain 503 by means of the gear wheel 123 , which drives the other gear wheel 203 , while with the other chain 503 the coupling is completed via the belt 143 ; this arrangement allows the two chains to rotate in opposite directions to each other .

[0052] The uprights 102 , column 302 , and portal 202 are advantageously made of steel , preferably stainless steel , and are constructed with a plurality of lightening openings and substantially box-shaped profiles , a feature that gives them strength and relative lightness .

[0053] The connection between the coupling structure 2 and the keel , as shown in Figures 7 and 8 , has the advantage of allowing the support structure to be released without the need to work inside the boat , and also provides , thanks to the seals 404 , a damping action that stabilizes the connection between the structure 2 and the keel , thereby improving the operation of the torpedo propulsion unit .

[0054] In the research that led to the present invention , the optimal configuration of the torpedo shape was studied, both in the bow and stern . This configuration changes depending on the speed and immersion of the torpedo ; where it has wings and is part of a hybrid foiling hull , the variation of the center of pressure on the torpedo at takeoff is also helpful .

[0055] Figure 9 shows the stern ogive movement system, which allows its angle to be adjusted by means of actuator 551 . The spherical joint , in cooperation with cardan joint 621 , allows the drive to be transferred correctly from motor shaft 631 to axle 611 . Advantageously, the motor shaft is connected to the cardan joint 621 via the reduction gear 641 ; the presence of the reduction gear is particularly useful in the case of electric motorization of the torpedo propulsion system . In particular , it is convenient to make the joint with the reduction gear in a single piece .

[0056] The mobilization of the stern ogive can be made easier if the motor , particularly in the case of an electric motor , is completely located inside the distal portion of the stern ogive , as shown in the variants illustrated in Figures 11 and 12 and described above . In the first case , illustrated in Figure 11 , efficient mobilization of the ogive is achieved, which effectively allows control of the propeller direction , while in the case of Figure 12 , control of the substantially watertight seal of the stern ogive mobilization mechanism is also achieved, which is completely contained within the distal portion of the same .

[0057] The bow ogive shown in Figure 10 shows three different types of control of its geometry variation ; the first control is provided by the possibility of oscillating the transverse plate 111 with respect to the transverse plate 151 by means of the actuator 141 . The second type of control is provided by the possibility of extending or retracting the piston element 421 with respect to the cylinder element 411 by means of the actuator 431 . The third type of control is provided by the possibility of inflating and deflating portion 461 , by means of supply and discharge ducts 471 and 481 , which can extend to the shape indicated by the dotted line 461 ’ . As shown in Figure 8 , the bow ogive can vary significantly in position relative to the fuselage axis , and this capability allows for an equally significant influence on the hydrodynamics of the propulsion unit . Advantageously, the inflatable portion of the ogive protects the torpedo propulsion unit from impact with submerged objects .

[0058] If the torpedo is equipped with lifting surfaces , it is extremely advantageous for these to have a high aspect ratio .

[0059] The apparent angle of attack also varies with the angle of attack of the torpedo , its speed, and its immersion . This latter feature is not found, for example , in the aerodynamics of aircraft flight .

[0060] For this last reason , a pivoting wing would be preferable to a fixed wing with flaps from the point of view of efficiency and the control system. The high aspect ratio would also lead, given the diameter of the central torpedo , to a wingspan greatly exceeding the outline of the deck and superstructure of most standard-width vessels , even in the case of catamarans .

[0061] Finally, it has been noted that one of the main problems limiting the application of hydrofoils is their exposure to debris and the potential damage this causes . In order to overcome these problems , it was therefore decided to apply a rotating wing system to the torpedo , which allows both the angle of attack to be controlled and the wing to be closed during maneuvers , in port or in areas where there is a risk of collision with the wings .

[0062] The torpedo propulsion unit designed in this way has numerous features that make it compatible with a variety of applications ; it can be used on a vessel designed specifically for this purpose or installed on an existing hull ; furthermore , the ability to control and adjust the distance of the propulsion system from the hull allows for much more effective use , which is further improved by the possibility of controlling the geometry, and therefore the hydrodynamics , of the torpedo ’ s ogives .

Claims

CLAIMS1. Torpedo propulsion unit (1) for vessels, equipped with a structure (2) for coupling to the keel (10) of a vessel hull, said structure (2) being movable, by means of appropriate actuators (3) , from a position of maximum distance from the keel (10) to a position of maximum proximity, all intermediate positions being continuously accessible; said structure (2) comprising a pair of uprights (102) connected at one end (112) to the keel of the hull of the vessel, arranged on the longitudinal axis of the hull at a given distance from each other, and at the opposite end being provided with sliding means (122) suitable for cooperating with a portal frame (202) arranged to slide between the two uprights (102) , and in which a column element (302) is provided, positioned between the uprights (212) of said portal (202) , the upper end of which is equipped with slide means (322) coupled to the uprights (212) of said portal (202) , and the lower end (312) of which is coupled to the fuselage (101) of said torpedo propulsion unit (1) , the drive means (3) of said slide means (122, 322) being positioned on said portal (202) .

2. Propulsion unit according to claim 1, wherein said drive means (3) comprise a gear motor (103) coupled to motion transmission means (123, 203, 133, 143, 403, 303) to the sliding means (122, 322) of the uprights (102) and the column element (302) .

3. Propulsion unit according to claim 2, wherein said transmission means comprise a plurality ofreturn means (303) coupled to a transmission belt or chain (503) .

4. Propulsion unit according to anyone of the preceding claims 1 to 3, wherein said coupling structure (2) is enclosed in a telescopic boxshaped body (4) formed by two or more portions of similar section, coaxial and concentric with each other .

5. Propulsion unit according to anyone of the preceding claims 1 to 4 , wherein the coupling structure (2) in extended configuration is approximately twice as long from one end to the other as in retracted configuration.

6. Propulsion unit according to anyone of the preceding claims 1 to 5 , wherein the slide means (122, 322) correspond to approximately one quarter of the length of the element, upright (102) or column (302) , to which they are associated.

7. Propulsion unit according to anyone of the preceding claims 1 to 6, wherein the coupling structure (2) is connected to the keel (10) of the boat by means of two plates (104, 204) which are coupled to each other at an opening (11) made in the keel (10) , taking between them the wall of the keel itself, said plates (104, 204) being provided with sealing means (404) that interact with the edge (12) of the opening (11) in the keel, the plate (104) facing the outside of the keel being coupled with the uprights (102) of the support structure.

8. Torpedo propulsion unit for vessels, in which the fuselage (101) has a substantially elliptical cross-section, the major axis being parallel to the horizontal plane, provided withtwo pairs of wings (301, 201) positioned along the centerline of the fuselage, respectively in the vicinity of the stern ogive (501) and the bow ogive (401) .

9. Torpedo propulsion unit according to claim 8, wherein the bow ogive (401) and the stern ogive (501) are movable and orientable.

10. Propulsion unit according to claim 8 or 9, wherein at least a portion (461) of the bow ogive (401) is made of semi-rigid or inflatable material .

11. Propulsion unit according to anyone of the preceding claims 8 to 10, wherein the bow ogive (401) is connected to the fuselage (101) of the torpedo (1) by means of an oscillating coupling between two plates (111, 151) facing each other, controlled by actuating means (141) .

12. Propulsion unit according to anyone of the preceding claims 8 to 11, wherein the stern ogive (501) comprises two portions, respectively proximal (511) and distal (521) , articulated to each other by means of a spherical joint (531, 541) , the motor shaft (631) being connected to the propeller drive shaft (611) of the propulsion unit by means of a cardan joint (621) located in said spherical joint (531, 541) , actuators (551) being provided for adjusting the relative position of the two portions (511, 521) .

13. Propulsion unit according to claim 12, wherein said motor shaft (631) is connected to said cardan joint (621) by means of a reduction gear (641) .

14. Propulsion unit according to claim 13, wherein the casing (651) of said reduction gear(641) is permanently coupled to said proximal portion (511) of the stern ogive (501) .

15. Propulsion unit according to anyone of the preceding claims 9 to 12, wherein the stern ogive (701; 801) comprises two portions (711, 721; 811, 821) articulated to each other by means of a spherical sector joint, pivoted on an axis (791; 851) perpendicular to the horizontal plane, one proximal portion (721; 821) of which is directly connected to the fuselage (101) of the torpedo, and the other distal portion (711; 811) entirely housing the engine (661) inside it, with means (771; 861, 871) for actuating the distal portion (711; 811) of the stern ogive.

16. Propulsion unit according to claim 15, wherein said means (771) are in the proximal portion (781) of the ogive, in correspondence with the spherical sector joint.

17. Propulsion unit according to claim 15, wherein said means (861, 871) are located inside the distal portion (811) of the ogive.

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