EP3943377B1 - Underwater craft less likely to be detected across great distances - Google Patents

Description

The invention relates to an underwater vehicle, in particular a submarine, with an external shape, wherein the shape is optimized to reduce detectability by means of active sonar. As a result, the distance from which the underwater vehicle is likely to be detectable can be significantly reduced.

Underwater vehicles, especially military submarines, currently usually have a roughly simplified cylindrical basic shape in the middle of the ship with a hemispherical bow and a conical stern. This shape is aerodynamic and can be easily manufactured as a single-hull or double-hull boat.

Today, sonar is used in particular to detect submarines, with detection preferably taking place over long distances, for example 100 km. This means that the sound waves from the sonar hit an underwater vehicle at a very shallow angle parallel to the water surface. To avoid detection, reflection of the sound waves must be avoided, particularly towards the transmitter, where the receiver is usually located. From this geometric consideration, it follows that the detectability of an underwater vehicle over long distances depends in particular on the reflection of sound at an angle of ± 20°, especially at an angle of ± 10°.

At short distances, other detection options are relevant, especially heat, sound emission, magnetic behavior and many others, so that detectability is regularly determined by other parameters.

However, a cylindrical body has the property of reflecting a wave practically vertically isotropically and thus emitting practically the same energy in all vertical spatial directions. This means that the detection in the critical flat angle range is not particularly low.

From the US$1,500,997 is a plate-shaped cladding of a submarine to reduce the signature.

From the GB 531 892 A is an electrically powered micro-submarine known.

From the DE 196 25 127 C1 A sound absorber is known for reducing the target dimension.

From the DE 197 54 333 A1 is a catamaran submarine known.

From the DE 1 196 531 A is an underwater vehicle with a curved surface.

From the US 2005/0145159 A1 A ship hull construction is known which has a curvature.

From the US 4 577 583 A is an underwater vehicle with a streamlined hull.

From the EP 0 850 830 A2 A submarine with three thrust bodies is known.

From the US 1 500 997 A is a known submarine design.

The object of the invention is to create an underwater vehicle which has a significantly reduced detection probability under the conditions of location over a distance.

This object is achieved by an underwater vehicle having the features specified in claim 1. Advantageous further developments emerge from the subclaims, the following description and the drawings.

The underwater vehicle according to the invention with reduced detection probability has an outer hull. The underwater vehicle has a bow section, a stern section and a midship section. The outer hull of the midship section has a polygonal cross-section transverse to the longitudinal direction of the underwater vehicle. Furthermore, the outer hull of the midship section has a curvature along the longitudinal direction of the underwater vehicle over the entire length of the midship section.

The polygonal cross-section itself is known for the targeted reflection of a detection wave in a direction deviating from the transmitter. This is used in aircraft construction or shipbuilding, for example the Sea Shadow, is known in principle. Here, large, flat and tilted surfaces are used as reflectors.

This alone has the disadvantage that higher order reflections also occur at other angles, meaning that detectability can also occur in the critical flat angle range. Furthermore, such an arrangement alone is not as effective for a submarine as it is for an aircraft, for example, because a submarine is surrounded by several interfaces where reflections to the transmitter can occur. Such interfaces are, for example, primarily the seabed and the water surface, but also areas that can result from the stratification of the sea water and represent reflection planes.

In order to minimize this disadvantage, according to the invention the outer shell of the midship section has a curvature along the longitudinal direction of the underwater vehicle. This causes both effects, reflection and dispersion, to occur. The effect is that the energy of the detection wave in the critical flat angle range can be significantly minimized. The curvature of the outer shell of the midship section extends over the entire length of the midship section. The curvature can have a variable radius of curvature over the length, but the radius of curvature must not be infinite. This would form a flat surface at least in one place, which would reflect an incoming beam without dispersion.

The midship section is arranged between the bow section and the stern section. The bow section has a length of 5% to 40%, preferably 5% to 30%, particularly preferably 5% to 20% of the total length of the underwater vehicle, with the bow section beginning at the bow of the underwater vehicle. The stern section has a length of 5% to 40%, preferably 5% to 30%, particularly preferably 5% to 20% of the total length of the underwater vehicle, with the stern section beginning at the stern of the underwater vehicle. The midship section thus has a length of 20% to 90%, preferably 40% to 90%, particularly preferably 60% to 90% of the total length of the underwater vehicle.

This allows the power of the wave reflected in the direction of the transmitter to be reduced by a factor of 10,000, for example, compared to a conventional cylindrical underwater vehicle. This reduces the distance at which detection is likely by up to of a magnitude. This significantly increases the freedom of movement of an underwater vehicle.

A triangle or a square can be used as a polygonal cross-section, for example, although these two polygons are less preferred due to the limited scope for adaptation. Polygons with 5 to 10 corners or sides are preferred, although the length of the sides preferably differs. Opposite sides are particularly preferred if they are the same length in pairs.

In an exemplary embodiment, which is not claimed, the polygonal cross-section has rounded corner areas. This is advantageous in terms of manufacturing technology and hydrodynamics.

In a further embodiment of the invention, the polygonal cross-section has a mirror plane perpendicular to the longitudinal axis. This means that the outer contour of the port side and the starboard side are the same.

In a further embodiment of the invention, the outer hull of the midship section has a curvature along the longitudinal direction of the underwater vehicle over the entire cross section, transverse to the longitudinal direction of the underwater vehicle.

In a further embodiment of the invention, the outer shell has at least a first segment, the first segment forming a first conic section in the longitudinal direction of the underwater vehicle or being composed of two or more conic sections. A segment is defined as an area which is limited at the top and bottom by the edges of the polygonal cross section. In the longitudinal direction, the extent of the segment is limited by the extent of the midship section. A conic section is a partial area of the shell of a cone. Particularly preferably, a first segment and a corresponding second segment on the opposite side of the ship have mirror-image conical sections. A cone is a geometric figure which is defined by height and radius. In a conical section, the radius of curvature thus changes continuously transversely to the longitudinal direction of the underwater vehicle. Of course, it can also be a conical section of an oblique cone in which the height axis is not centered on the circular base.

In a further embodiment of the invention, the outer shell has at least a third segment, wherein the third segment forms a third conic section at least in sections, preferably completely, in the longitudinal direction of the underwater vehicle, wherein the height and/or radius of the third conic section are different from the height and/or radius of the first conic section.

In a further embodiment of the invention, the cone of the conic section has a height, wherein the ratio of height to length of the underwater vehicle is between 0.5 and 1,000, preferably between 3.5 and 130, particularly preferably between 8.0 and 35.

In a further embodiment of the invention, the cone of the conic section has a diameter, wherein the ratio of cone diameter to length of the underwater vehicle is between 2 and 100, preferably between 6 and 50, particularly preferably between 10 and 20.

In a further embodiment of the invention, the underwater vehicle has a tower in the midship section. The tower particularly preferably has outer walls inclined by at least 10°, particularly preferably by at least 20°, relative to the vertical.

Particularly preferably, the tower has the same angle as the side of the polygonal cross-section adjacent below the tower.

According to the invention, the curvature of the midship section has a radius of curvature, wherein the ratio of radius of curvature to length of the underwater vehicle is between 5 and 1,000, preferably between 10 and 250, particularly preferably between 25 and 100.

The curvature of the midship section does not have to be constant over the entire length. The curvature of the midship section can increase towards the sections, particularly adjacent to the bow section and/or stern section, for example to create a transition. Preferably, the curvature increases in the transition from the midship to the bow section and decreases in the transition from the midship to the area of the stern section.

For example, for an underwater vehicle with a length of 80 m, this results in a curvature of the midship section which causes an increase in the cross-section of an imaginary circle enclosing the midship compared to an uncurved, straight cylinder shape of about 0.5 m to 2 m, whereby the tower or other superstructures or attachments are not taken into account here.

In a further embodiment of the invention, the polygonal cross-section has a widest point, wherein the widest point of the polygonal cross-section is arranged below or above the center, wherein the center defines half the height of the polygonal cross-section.

The deviation from a symmetrical design makes it possible to specifically deflect a larger part of the incoming detection wave in the same direction. If the widest point is below the middle, the larger part is reflected upwards and thus to the water surface. If the widest point is above the middle, the larger part is reflected downwards and thus to the seabed. The first variant is preferred for boat stability, the second for reducing the target size.

In a further embodiment of the invention, the widest point of the polygonal cross-section is arranged at least 10%, preferably at least 20% of half the height of the polygonal cross-section below or above the center.

In a further embodiment of the invention, all planes of the polygonal cross-section have an inclination of at least 10°, preferably of at least 20°, relative to the vertical.

In a further embodiment of the invention, all planes of the polygonal cross-section have an inclination of 10° to 40° or 50° to 80° relative to the vertical. The angle of 45° should also be avoided, since the incoming wave is reflected, for example, onto the water surface, reflected back from there and then reflected directly back to the transmitter. Although the intensity is reduced by the multiple reflection, it is still significantly higher than at other angles.

In a further embodiment of the invention, the outer shell has a sound-absorbing property. In addition to the optimized geometry, the outer shell can be made of a consist of, contain or be coated with sound-absorbing material. Since absorption can never be complete, the two effects combine positively.

In a further embodiment of the invention, the outer shell is essentially reflective and/or absorbent for sound waves in the frequency range from 100 Hz to 100 kHz, in particular in the range from 1 kHz to 25 kHz. Since other, non-optimized structures can be arranged under the outer shell, the transmission through the outer shell must be kept as low as possible. The sum of the reflectance, absorbance and transmittance is by definition 1. It is considered to be essentially reflective and/or absorbent if the reflectance and/or transmittance is at least 0.75, preferably at least 0.9, particularly preferably at least 0.95.

According to the invention, the underwater vehicle has a substantially cylindrical pressure hull under the outer hull.

In a further embodiment of the invention, the outer shell does not completely enclose the cylindrical pressure body. The pressure body thus forms the outer shell in some areas. This can be the case, for example, in less critical places, for example on the underside.

In a further embodiment of the invention, sensors, in particular passive sonar sensors and/or fuel reservoirs, are arranged between the outer hull and the pressure hull.

Fuel storage includes all forms of storage goods that are required to operate the submarine, for example gasoline or diesel tanks, hydrogen storage, for example in the form of compressed gas storage, liquid hydrogen storage or metal hydride storage, oxygen storage, for example in the form of compressed gas storage or liquid oxygen storage, methanol storage, ethanol storage, batteries, accumulators and compressed gas storage for gas turbines, but also autonomous or remote-controlled underwater vehicles, weapons, such as torpedoes or missiles, or decoys.

In a further embodiment of the invention, a propeller is arranged at the level of the widest point of the outer skin.

In a further embodiment of the invention, the underwater vehicle is a submarine. Preferably, the underwater vehicle is a military underwater vehicle, particularly preferably a military submarine.

• Fig. 1 Aufsicht auf ein erfindungsgemäßes Unterwasserfahrzeug
• Fig. 2 Querschnitt eines ersten beispielhaften Unterwasserfahrzeugs
• Fig. 3 Querschnitt eines zweiten beispielhaften Unterwasserfahrzeugs
• Fig. 4 Querschnitt eines dritten beispielhaften Unterwasserfahrzeugs
• Fig. 5 Querschnitt eines vierten beispielhaften Unterwasserfahrzeugs

The underwater vehicle according to the invention is explained in more detail below using embodiments shown in the drawings.

• Fig.1 View of an underwater vehicle according to the invention
• Fig.2 Cross section of a first exemplary underwater vehicle
• Fig.3 Cross section of a second exemplary underwater vehicle
• Fig.4 Cross section of a third exemplary underwater vehicle
• Fig.5 Cross section of a fourth exemplary underwater vehicle

In Fig.1 the top view shows an underwater vehicle 10 with a bow section 20, a midship section 30 and a stern section 40, the underwater vehicle having a rudder 60, here in the form of a cruiser, and a propeller 70 in the stern section 40. The underwater vehicle 10 has an outer hull 50, which has a curvature of the midship section in the longitudinal direction of the underwater vehicle 10, as can be seen in comparison to a pressure hull 80 shown simplified as a cylinder. In practice, the pressure hull 80 will also have rounded ends at the bow and stern, preferably hemispherical ends, which has been neglected here for the sake of simplicity. The pressure hull 80 also does not have to take up the full length. In particular, weapon barrels can be arranged in the bow.

Fig.2 shows a first example cross-section. The outer shell 80 has a hexagonal cross-section, the widest point 100 is exactly at the height of the center 90, which is formed by the center of the cylindrical pressure body 80. This point is used here and below as the center according to half the height of the polygonal cross-section, since these practically coincide, but the center is easier to represent visually. All surfaces of the outer shell 50 have an angle of 30° or 90° with respect to the vertical.

Fig.3 shows a second exemplary cross-section. The outer shell 80 has an irregular hexagonal cross-section, with the widest point 100 clearly above which is arranged at 90° in the middle. This means that a large part of the incoming waves are reflected to the seabed, which further minimizes the probability of detection.

Fig.4 shows a third exemplary cross-section. The outer shell 80 has an irregular hexagonal cross-section, with the widest point 100 being arranged significantly below the center 90. As a result, a large part of the incident waves are reflected to the water surface, but the center of gravity of the underwater vehicle 10 can be arranged lower. This is advantageous for the stability of the underwater vehicle 10.

As opposed to Fig. 2 to Fig. 4 shows Fig.5 a cross-section with rounded corners, which is otherwise basically the same as the second exemplary cross-section from Fig.3 In addition, fuel storage 110 and sonar sensors 120 are arranged between the outer hull 50 and the pressure hull 80.

Alone Fig. 2 to Fig. 5 The cross-sections shown are mirror-symmetrical. This is not necessary, but preferred.

Reference symbols

10

Underwater vehicle

20

Bow section

30

Central nave section

40

Rear section

50

Outer shell

60

Rudder

70

propeller

80

Pressure hull

90

center

100

widest point

110

Fuel storage

120

Sonar sensors

Claims (12)

1. Underwater vehicle (10) with reduced probability of detection, wherein the underwater vehicle (10) has an outer hull (50), wherein the underwater vehicle (10) has a bow section (20), a stern section (40) and a midship section (30), wherein the outer hull (50) of the midship section (30) has a polygonal cross-section transverse to the longitudinal direction of the underwater vehicle (10), wherein the outer hull (50) of the midship section (30) has a curvature along the longitudinal direction of the underwater vehicle (10) over the entire length of the midship section (30), wherein the underwater vehicle (10) has a substantially cylindrical pressure hull (80) under the outer hull (50), characterised in that that the curvature of the midship section has a radius of curvature, wherein the ratio of the radius of curvature to the length of the underwater vehicle (10) is between 5 and 1.000, wherein the polygonal cross-section has three to 10 corners.
2. Underwater vehicle (10) according to claim 1, characterised in that the polygonal cross-section has a mirror plane perpendicular to the longitudinal axis.
3. Underwater vehicle (10) according to one of the preceding claims, characterised in that the outer hull (50) of the midship section (30) has a curvature transverse to the longitudinal direction of the underwater vehicle (10) over the entire cross-section along the longitudinal direction of the underwater vehicle (10).
4. Underwater vehicle (10) according to claim 3, characterised in that the outer shell (50) forms a conical section in the longitudinal direction of the underwater vehicle (10) or is composed of two or more conical sections.
5. Underwater vehicle (10) according to one of the preceding claims, characterised in that the underwater vehicle (10) has a turret in the midship section (30).
6. Underwater vehicle (10) according to one of the preceding claims, characterised in that the ratio of the radius of curvature to the length of the underwater vehicle (10) is between 10 and 250, particularly preferably between 25 and 100.
7. Underwater vehicle (10) according to one of the preceding claims, characterised in that the polygonal cross-section has a widest point (100), wherein the widest point (100) of the polygonal cross-section is arranged below or above the centre (90), wherein the centre (90) is defined as half the height of the polygonal cross-section.
8. Underwater vehicle (10) according to claim 7, characterised in that the widest point (100) of the polygonal cross-section is arranged at least 10%, preferably at least 20% of half the height of the polygonal cross-section below or above the centre (90).
9. Underwater vehicle (10) according to one of the preceding claims, characterised in that all planes of the polygonal cross-section have an inclination of at least 10°, preferably of at least 20°, relative to the vertical.
10. Underwater vehicle (10) according to one of the preceding claims, characterised in that all planes of the polygonal cross-section have an inclination of 10° to 40° or 50° to 80° relative to the vertical.
11. Underwater vehicle (10) according to one of the preceding claims, characterised in that the outer shell (50) has a sound-absorbing property.
12. Underwater vehicle (10) according to one of the preceding claims, characterised in that sensors, in particular passive sonar sensors (120), and/or fuel accumulators (110) are arranged between the outer hull (50) and the pressure hull (80).

Images