SURFACE PLATFORM, ESPECIALLY FOR TRACKING SUBMARINES

Description

[0001] The invention relates to a watercraft which is particularly designed for detecting submarines or other contacts in the water.

[0002] Over the past thirty years, the number of military vessels has declined, especially in Western Europe. Newer units are often no longer focused on submarine warfare, but rather, as the term "multi-role combat ship" suggests, are designed for a very broad range of uses. Submarines also have a greatly expanded range of missions, despite significantly fewer submarines. Today, helicopters are heavily relied upon for submarine warfare. However, these have a limited operational range due to weather and fuel constraints.

[0003] This makes it difficult to detect, track, and observe foreign submarines, while preferably remaining unnoticed. A further challenge is how to make this possible, for example, in the shallow Baltic Sea, as well as in the North Sea or North Atlantic.

[0004] A watercraft with a retractable keel is known from US 2015 / 0210359 A1.

[0005] An adjustable ballast for a sailing ship is known from US 2019 / 0016415 A1.

[0006] A submarine for combating oil spills is known from US 2014 / 319076 A1.

[0007] An unmanned underwater vehicle is known from DE 10 2006 045686 B3.

[0008] FR 2 768 393 A1 discloses a method for improving the stealth capability of conventional submarines.

[0009] A semi-submersible is known from GB 2 361 458 A.

[0010] From KR 2016 0028744 A, a structure for avoiding interference between towed sonar and propeller in a submarine as well as a submarine with such a structure and a sonar with towed arrangement, and an implementation method using the same are known.

[0011] A submarine and a method for its operation are known from US 2019 / 135387 A1.

[0012] The fundamentals of submarine propulsion are known from GABLER ULRICH: "PROPULSION PLANTS", 1 January 2000 (2000-01-01), SUBMARINE DESIGN, BERNARD UND GRAEFE VERL, BONN, DE, PAGE(S) 63 - 81, XP007908945, ISBN: 978-3-7637-6202-6.

[0013] From WO 2019 / 207263 A1 a system for deploying and retrieving an autonomous underwater device and a method for using it are known.

[0014] A fluid vehicle with a reduced signature is known from DE 10 2015 209723 A1.

[0015] The object of the invention is to create a simple and inexpensive platform that can locate and track a foreign submarine.

[0016] This object is achieved by a watercraft having the features specified in claim 1. Advantageous further developments emerge from the subclaims, the following description, and the drawings.

[0017] The watercraft according to the invention is designed as a semi-submersible boat. The watercraft is designed for unmanned operation. This means that the watercraft can be operated autonomously or remotely. Remote-controlled operation is preferred. However, it is common for watercraft designed for unmanned operation to also have a control station for manual operation. This can be used temporarily, for example, to enable immediate human intervention for legal reasons. On the other hand, manual operation can be used for operating modes in which automation or remote control would be complex or ineffective. For example, navigation into or out of a harbor can be manual, particularly since a high degree of interaction with other watercraft may be necessary here.Such operations can be carried out by a pilot, as is usual with ocean-going vessels.

[0018] The watercraft has a hull and a tower arranged on the hull. The watercraft is semi-submersible, which means that the vast majority of the buoyancy-generating structure is below the waterline. In the case of this invention, the hull is completely submerged in water during normal semi-submerged operation, while the tower arranged on the hull continually projects above the waterline. In contrast to other watercraft, the hull is completely surrounded by water, apart from the connecting surface of the tower, so that preferably at least 3 / 4, preferably at least 7 / 8, very particularly preferably 11 / 12 of the surface of the hull is in contact with the surrounding water. The hull has at least one first watertight hull region and at least one first water-flooded hull region.The watercraft has a propulsion unit in the first watertight hull area. The watercraft has at least one first sonar for detecting submarines.

[0019] The semi-submersible craft according to the invention can also be described as a monohull with a small waterline area, analogous to a twin hull with a small waterline area (Small Waterplane Area Twin Hull (SWATH)), in which only a portion of the conning tower protrudes above the waterline. The largest part of the craft lies below the waterline, while the portion of the conning tower above the waterline is small. The hull is preferably torpedo-shaped.

[0020] The watercraft according to the invention offers a number of advantages. Firstly, due to its sonar capability, it can perform the task of detecting submarines, particularly in a naval formation, as frigates and destroyers without this capability are increasingly in service or are being built, as these ships must cover increasingly broader tasks. Secondly, however, due to its clear focus solely on the detection of enemy submarines, combined with its unmanned design, the watercraft is comparatively small, simple, and inexpensive.

[0021] Furthermore, due to the unmanned design, a watercraft according to the invention can also be used at a greater distance from a convoy of ships, since such a unit does not have to be kept under the complete protection of the convoy, since the loss of an unmanned object is significantly less serious.

[0022] The semi-submersible design has two additional advantages. Firstly, only a small part, the upper section of the turret, protrudes above the water surface, which lowers the radar cross-section (RCS) compared to comparable purely surface vessels, such as the United States Navy's Anti-Submarine Warfare Continuous Trail Unmanned Vessel (ACTUV), and thus reduces the likelihood of detection by other surface units or aircraft. Secondly, the semi-submersible has the advantage over an underwater design in that, due to the constant contact with the surface, oxygen from the atmosphere is always available, exhaust gases can also be released into the atmosphere, and a pressure hull only needs to be designed for very shallow depths. This makes the design of a semi-submersible comparatively simple and inexpensive.

[0023] In a further embodiment of the invention, the semi-submersible boat is designed as a monohull with a small waterline area. The semi-submersible boat cannot surface, meaning its hull cannot break the waterline under its own power. This also largely eliminates the need for ballast tanks; only trim tanks, which can also compensate for weight changes due to fuel consumption, are advantageously provided. This allows the draft to be kept constant.

[0024] In a further embodiment of the invention, the watercraft has a towed sonar. A receiving device for the towed sonar is arranged in the first water-flooded hull area. A towed sonar is particularly well suited as the first sonar within the meaning of the invention because, due to its length and the distance to all objects on the watercraft that generate noise, it enables very good passive detection of submarines. Furthermore, the towed sonar is not limited to the length of the watercraft, whereby the greater detection extent facilitates locating, i.e. determining the position of a contact. The receiving device is, for example and preferably, a winch onto which the towed sonar is wound in order to take it on board.

[0025] In a further embodiment of the invention, the watercraft has a guide for the towed sonar. This guide allows the towed sonar to be guided past the propeller within a protected environment. This prevents the towed sonar from coming into contact with the propeller and being damaged in the process. The guide can be hydrodynamically molded to a skeg or the ship's hull, i.e., by a smooth transition of the surface, and can be long enough to extend beyond the propeller aft, preferably at least half the propeller diameter.

[0026] In a further embodiment of the invention, the watercraft has at least one first watertight tower area in the tower. The first watertight tower area is advantageous because, due to the design, waves could otherwise easily reach or even over the tower and thus water could penetrate. The first watertight tower area is arranged here to protect the devices arranged around the tower and also to prevent an unwanted increase in weight in the high-lying tower. The first watertight tower area preferably closes off the tower in the horizontal cross-section so that no water can penetrate from the outside through the tower into the ship's hull. This makes it possible to operate the watercraft even when the waves are higher than the tower above the waterline.

[0027] In a further embodiment of the invention, there is a watertight connection, for example in the form of a lock, between the first watertight tower area and the first watertight hull area.

[0028] In a further embodiment of the invention, the turret has a widening above the waterline. The widening can be in the ship's longitudinal direction, transverse to the ship's longitudinal direction, or both in the ship's longitudinal direction and transverse to the ship's longitudinal direction. This makes it possible to create a larger interior space in the turret that lies above the waterline, while keeping the waterline area, i.e. the area where the waterline is interrupted, to a minimum. The larger interior space can preferably be designed to be watertight. Furthermore, the larger interior space can be high enough for a person to stand upright. The larger interior space can create additional space, for example for people to stay or for a manual control station.

[0029] In a further embodiment of the invention, the watercraft has sonar evaluation electronics. The sonar evaluation electronics are preferably arranged in the first watertight turret area and connected to the towed sonar or other sonar devices in order to evaluate the signals from the towed sonar or the sonar devices. While an arrangement near the first sonar and thus within a watertight hull area would be advantageous due to shorter signal path lengths, the drive unit in the ship's hull generates heat during operation, which is problematic for the electronics. Therefore, a separation between the drive unit in the watertight hull area and the sonar evaluation electronics in the watertight turret area is expedient.

[0030] The term "sonar evaluation electronics" is to be understood broadly within the meaning of the invention. Since the preferred operating mode for the watercraft according to the invention is remote-controlled operation, the sonar data processed by the sonar evaluation electronics is transmitted via radio to a unit not located on the watercraft, where it is further processed. The unit can be, for example, a ship or a land-based base, which can then, for example, initiate target engagement, for example, with an on-board helicopter. Therefore, the processing of the sonar data can only be carried out to the extent that the raw data is processed to such an extent that it can be transmitted more quickly, for example in real time and / or encrypted, to the unit using suitable communication devices.

[0031] In a further embodiment of the invention, the drive unit comprises a diesel generator and a traction motor. To supply the diesel generator, the tower has at least one fresh air supply and one exhaust air exhaust. The traction motor is particularly preferably an electric traction motor.

[0032] In a further embodiment of the invention, the diesel generator is arranged in a first watertight hull area and the traction motor is arranged in a second watertight hull area.

[0033] In a further embodiment, the watertight hull area has receptacles for transport rails. During maintenance, transport rails can be inserted into these receptacles to enable components to be moved longitudinally. For maintenance purposes, the hull preferably has at least one hatch. The transport rails allow the components to be positioned below the hatch and lifted out of the ship's hull, eliminating the need to cut open the hull. Rotating the components may be necessary to keep the hatch as small as possible.

[0034] In a further embodiment of the invention, the watercraft has an accumulator. This can be used to better compensate for power fluctuations. Preferably, the accumulator is not designed for continuous operation of the entire watercraft for hours or days, as is the case with submarines. This results in significant savings in size and weight. This is also unnecessary in a semi-submersible vessel due to the constant availability of oxygen from the environment and the possibility of exhaust gases being released.

[0035] In a further embodiment of the invention, the exhaust air outlet has a gooseneck. A gooseneck ensures that, in the event of flooding of the tower and thus also the exhaust at the end of the exhaust air outlet, any water entering must first rise upwards against the direction of the outgoing exhaust gases before the water can reach the sloping area and thus the ship's hull. Without the gooseneck, the water could flow directly downwards into the ship's hull to the diesel generator.

[0036] In a further embodiment of the invention, at least a first diesel tank is arranged in the water-flooded hull area. Preferably, all diesel tanks are arranged in the water-flooded hull area. In particular, the diesel tanks are arranged either in pairs opposite each other on the starboard and port sides or along the longitudinal axis. This enables even fuel consumption, which minimizes the impact on the vessel's attitude and minimizes the need for trimming due to fuel consumption.

[0037] In a further embodiment of the invention, the diesel tanks are designed to be self-compensating. For example, and in particular, the diesel tanks each have at least one plastic shell inside, with ambient water being introduced into the plastic shell, while the fuel is drawn from the diesel tanks on the other side. During refueling, the process is reversed: the fuel flows into the diesel tanks and pushes the water from the plastic shells back into the environment. As a result, the trim does not change due to the weight of the consumed fuel, but only due to the weight difference between the fuel and the water replacing the fuel. This allows the trim system of the watercraft to be designed accordingly smaller and simpler.

[0038] In a further embodiment of the invention, the watercraft has a downwardly extendable keel. At least a first group of sonar sensors is arranged in the downwardly extendable keel. The extendable keel can be extended by at least 2 m, preferably at least 3 m, particularly preferably at least 5 m. The extendable keel can be extended by a maximum of 15 m, preferably a maximum of 10 m. The sonar sensors are in a fixed spatial relationship to one another, i.e. the position of all sensors is known and constant. Of course, changes can occur, for example due to temperature changes, but these are small and generally negligible. The first group of sonar sensors preferably has a length of 5 m to 30 m, particularly preferably 10 m to 20 m. The first group of sonar sensors preferably has 50 to 500 hydrophones arranged rigidly relative to one another, particularly preferably 100 to 250 hydrophones arranged rigidly relative to one another.For example, and in particular, the first group of sonar sensors is designed for a frequency range of 10 Hz to 5 kHz.

[0039] The advantage is that the sonar is positioned further down from a comparatively small platform and therefore further away from the water surface. Although towed sonars are known that make this possible, towed sonars also have disadvantages. Firstly, the hydrophones in a towed sonar are not truly stationary relative to one another. Secondly, the towed sonar can move, sag, or stretch, i.e. change its length. In addition to these factors that affect the spacing of the hydrophones, a towed sonar can also be an obstruction and even get caught in shallow water. However, if the first group of sonar sensors is integrated into an extendable keel, these problems are eliminated and a clearer sonar image can be created.

[0040] As a result, the watercraft according to the invention can close a currently existing capability gap in current fleets by providing a simple and therefore cost-effective platform with which the necessary capabilities can be supplemented.

[0041] In a further embodiment of the invention, the downwardly extendable keel has a first group of sonar sensors and a second group of sonar sensors, wherein the first group of sonar sensors and the second group of sonar sensors are arranged longitudinally next to one another and wherein the main detection plane of the first group of sonar sensors is directed to starboard and towards the seabed, preferably at an angle of 35° ± 20° downwards, and wherein the main detection plane of the second group of sonar sensors is directed to port and towards the seabed, preferably at an angle of 35° ± 20° downwards. This enables optimal location of submerged submarines.

[0042] In a further embodiment of the invention, the extendable keel is extendable by at least 2 m, preferably at least 3 m, particularly preferably at least 5 m. Furthermore, the extendable keel is extendable by a maximum of 15 m, preferably a maximum of 10 m. This magnitude represents a significant improvement in sonar performance. A greater distance, however, would require massive guide elements to ensure the relative position of the first group and optionally the second group of sonar sensors relative to the watercraft, for example in the case of crosscurrents. A bend of just 1 ° here can lead to a mislocation of almost one nautical mile at a distance of 50 nautical miles to the target. Alternatively, the exact position of the extendable keel in relation to the hull of the watercraft would have to be recorded to compensate for this error.

[0043] In a further embodiment of the invention, the extendable keel has a towed sonar. The towed sonar can be a passive towed sonar. However, it can also be an active towed sonar. For example, and in particular, the towed sonar has a length of 200 m to 1500 m. For weight and stability reasons, it may be advantageous if the extendable keel does not have a device for retrieving the towed sonar, but rather if the towed sonar is attached and removed by an accompanying vessel.

[0044] In a further embodiment of the invention, the turret cuts through the water surface when operating semi-submerged. This allows the actual hull to be completely submerged. The most important advantage of this design is the minimization of the vessel's vertical movements in rough seas, thus making it independent of the sea state. This seakeeping capability benefits the vessel's improved sonar capabilities, without requiring the construction of a submarine with a complex pressure hull.

[0045] In a further embodiment of the invention, the watercraft has at least one control cell for controlling the draft. Particularly preferably, the watercraft has a first control cell on the reverse and a second control cell on the stern. The control cell can be used to keep the draft constant through active control, particularly during semi-submerged operation.

[0046] In a further embodiment of the invention, the watercraft is diesel-powered. The semi-submerged design allows for a constant supply of fresh air and the removal of exhaust gases. At the same time, diesel generators are readily available, reliable, and easy to resupply with new fuel, even at sea, since this is already available for existing vessels. Particularly preferably, the watercraft has two diesel generators to ensure redundancy.

[0047] In a further embodiment of the invention, the watercraft has an electric traction motor.

[0048] In a further embodiment, the watercraft has a propeller connected to the propulsion motor via a shaft. Particularly preferably, the watercraft has two counter-rotating propellers, also mounted on one axle. The use of two counter-rotating propellers does not generate any torque on the watercraft. In a further preferred embodiment, the propeller or two propellers are encased in a housing, resulting in a waterjet propulsion system.

[0049] In a further embodiment of the invention, the watercraft has an accumulator for storing electrical energy. Particularly in combination with a diesel generator and an electric traction motor, this allows for temporary provision of more energy for higher speeds, for example, during a sprint.

[0050] In a further embodiment of the invention, the watercraft additionally has a bow sonar with a circular hydrophone arrangement.

[0051] In a further embodiment of the invention, the watercraft can be navigated with the keel retracted in the surfaced state. When surfaced, the hull, which is completely submerged in the semi-submerged state, breaks the water surface. This, along with the retraction of the keel, significantly reduces the draft, allowing navigation even in shallow waters or in harbors. For this purpose, a manual control station is located at the top of the tower.

[0052] In a further embodiment of the invention, the watercraft is an unmanned watercraft. The watercraft has a first communication device, wherein the first communication device is permanently arranged above the water surface. The design as an unmanned watercraft and thus the omission of any device for supporting a crew enables a smaller and thus much more cost-effective platform. Since the watercraft always has a part above the waterline, a first communication device, for example a satellite communication device, can easily be arranged here. This allows the watercraft to be remotely controlled at any time, even if the watercraft has autonomous operating mode. Secondly, the watercraft can also transmit contact data, in particular of a tracked submarine, to the rest of the fleet via the first communication device.

[0053] In a further embodiment of the invention, the watercraft has a second communication device. For example, and preferably, the first communication device is designed for long-range communication, for example via satellite communication, and the second communication device is designed for short-range communication, for example via radio. This allows a ship, for example a cruiser, a destroyer, a frigate, a corvette, or even a task force support ship, to assume command and remote control of the watercraft, particularly within line of sight. To further secure this connection, the second communication device can also be an optical communication device.

[0054] In a further embodiment of the invention, the watercraft has at least one effector, in particular a lightweight torpedo. If, for example, a submarine being tracked by the watercraft approaches a critical facility, the effector could be deployed, particularly remotely.

[0055] In a further embodiment of the invention, the watercraft has an active sonar. This makes it possible to use cooperative bistatic detection methods in cooperation with another watercraft, including another watercraft according to the invention, and thus to precisely locate even signature-optimized submarines. It is advantageous if the actively emitting watercraft according to the invention is designed as an unmanned and comparatively cost-effective platform, since the active transmitter is detected practically automatically with a bistatic method and is therefore exposed to the highest risk of destruction.

[0056] In a further embodiment of the invention, the inventive vessel serves to add submarine detection capabilities to a convoy. Many ships in use today are not equipped with the full sonar capacity to detect submarines. However, virtually any ship capable of carrying an onboard helicopter has the capability to engage them. Thus, by combining a inventive vessel with a ship equipped with an onboard helicopter, efficient anti-submarine protection for a convoy can be created.

[0057] In a further embodiment of the invention, the ship's hull has an outer shell made of fiber-reinforced plastic. This type of construction is common for submarines, where an inner shell is formed by a pressure hull, and between the pressure hull and the outer shell there is a water-filled area in which, for example, sensors or fuel tanks can be located.

[0058] According to the invention, the watercraft has a supporting frame structure. Preferably, both the outer shell and the pressure-resistant shell of the watertight hull area are arranged on the frame structure and connected to each other in a load-bearing manner.

[0059] In a further embodiment of the invention, the watercraft has a displacement of 100 t to 1000 t, preferably 150 t to 500 t, more preferably 200 t to 400 t. This size enables an optimal compromise for long service life at sea, especially for an unmanned platform, while maintaining low costs.

[0060] In In a further embodiment of the invention, the watercraft has a length of 20 m to 60 m.

[0061] In In a further embodiment of the invention, the watercraft has a draft of 3 m to 7 m in the surfaced state and a draft of 10 m to 18 m in the semi-submerged state. The deeper the draft in the semi-submerged state (with the keel extended), the deeper the sonar sensors are and the more stable they are against the movement of the water surface. At the same time, a shallow draft in the surfaced state with the keel retracted allows for good maneuverability in shallow water and access to all ports.

[0062] In a further embodiment of the invention, the watercraft has underwater effectors. In particular, the watercraft has lightweight torpedoes, for example, with a diameter of 325 mm. These are typically used by helicopters, aircraft, or surface units to combat submarines. Alternatively or additionally, the watercraft can have depth charges as underwater effectors. For this purpose, the watercraft is particularly preferably operated in a remote-controlled mode, so that the use of the underwater effectors can and must be authorized remotely by a human.

[0063] In a further embodiment of the invention, the watercraft has surface effectors. In particular, the watercraft has a close-range defense system as a surface effector. The advantage of this system is that both aircraft and small surface vehicles, such as inflatable boats, can be effectively engaged at close range. For this purpose, the watercraft is particularly preferably operated in a remote-controlled mode, so that the use of the surface effectors can and must be authorized remotely by a human.

[0064] In a further embodiment of the invention, the watercraft is designed to accommodate a mine belt, such as those known, for example, from the 206-class submarine. This allows the watercraft, in exceptional cases, to be used for another purpose: hunting submarines by laying mines.

[0065] The watercraft according to the invention is explained in more detail below using an embodiment shown in the drawings. Fig. 1 first watercraft in semi-submerged condition Fig. 2 first watercraft in surfaced state Fig. 3 second watercraft

[0066] In Fig. 1 a first watercraft 10 is shown in a semi-submerged state and with the keel 20 extended, in Fig. 2 the first watercraft 10 is shown in the surfaced state with the keel 20 retracted.

[0067] The first watercraft 10 has a keel 20 with a first group of sonar sensors 30, which can be extended downwards by, for example, 7 m and retracted again. This allows a very deep arrangement of the first group of sonar sensors 30 in the semi-submerged state with the keel 20 extended. In the semi-submerged state, only the upper end of the tower 40 protrudes above the water surface 50, and only the cross-section of the tower 40 intersects the water surface 50. This ensures a very stable position of the watercraft 10. For propulsion, the first watercraft 10 has a diesel generator 60, the electricity from which drives a traction motor 70, which in turn drives a propeller 100 via a shaft. The diesel generator 60 draws fuel from the diesel tank 80. The diesel generator 60 takes in fresh air through a fresh air supply and exhaust air 90, which runs through the tower 40, and releases the exhaust air again via these.A bow sonar 110 is arranged in the bow of the watercraft 10. Furthermore, the first watercraft 10 has a gun barrel 120 for accommodating a lightweight torpedo. A first communication device 130 in the form of a satellite communication system is arranged at the upper end of the turret 40, and thus permanently above the water surface 50. Furthermore, the first watercraft 10 has control cells 140, via which the draft can be regulated. For this purpose, water is pumped from the surrounding area into the control cells 140 or released from the control cells 140 into the surrounding area. This allows the draft to be kept constant even over extended periods, particularly during semi-submerged operation.

[0068] For example, the hull of the watercraft 10 has a diameter of 5 m, the turret 40 has a height of 7 m above the hull, and the keel can be extended, for example, 7 m below the hull. Thus, the first group of sonar sensors 30 would be very stably positioned approximately 15 m to 16 m below the water surface 50, which would significantly facilitate the location of a submarine being tracked. At the same time, a minimum draft of approximately 6 m would allow access to most ports.

[0069] In Fig. 3A second watercraft 10 is shown. The second watercraft 10 has a hull 150 and a turret 40. The hull 150 contains a first watertight hull section 160, a second watertight hull section 180, and a first watertight hull section 230. A diesel generator 60 is arranged in the first watertight hull section 160. The diesel generator 60 is supplied with ambient air via the fresh air supply and exhaust air outlet 90, which runs through the turret 40, and can discharge exhaust gases. The diesel generator 60 receives fuel from a diesel tank 80, which is arranged in the first watertight hull section 230. The watercraft 10 is driven by means of the traction motor 70, which is arranged in the second watertight hull section 180 and drives the propeller 100. A receiving device 210 for the towed sonar 200 is arranged between the first watertight hull area 160 and the second watertight hull area 180.To ensure that the towed sonar 200 can be guided smoothly past the propeller 100, the towed sonar 200 extends through the skeg 190. The data acquired by the towed sonar 200 are evaluated in the sonar evaluation electronics 220, which is located in the first watertight tower area 170. The sonar data can then be transmitted from the sonar evaluation electronics 220 to an accompanying vessel via the first communication device 130. Reference symbol

[0070] 10Vessel 20Keel 30First group of sonar sensors 40Turret 50Water surface 60Diesel generator 70Propulsion motor 80Diesel tank 90Fresh air supply and exhaust air 100Propeller 110Bow sonar 120Gun barrel 130First communication device 140Control cell 150Hull 160First watertight hull section 170First watertight turret section 180Second watertight hull section 190Skeg 200Towed sonar 210Recording device 220Sonar evaluation electronics 230First watertight hull section 240Outer hull

Claims

1. Watercraft (10), wherein the watercraft (10) is designed as a semi-submersible boat, wherein the watercraft (10) is designed for unmanned operation, wherein the watercraft (10) has a hull (150) and a turret (40) arranged on the hull (150), wherein the hull (150) has at least one first watertight hull region (160) and at least one first water-flooded hull region (230), the watercraft (10) having a drive unit in the first watertight hull region (160), the watercraft (10) having at least a first sonar for detecting submarines, wherein the watercraft (10) has a load-bearing frame structure.

2. Watercraft (10) according to claim 1, characterised in that the watercraft (10) has a towing sonar (200), wherein a receiving device (210) for the towing sonar (200) is arranged in the first water-flooded hull region (230).

3. Watercraft (10) according to claim 2, characterised in that the watercraft (10) has a guide for the towing sonar (200).

4. Watercraft (10) according to one of the preceding claims, characterised in that the watercraft (10) has at least one first watertight turret region (170) in the turret (40).

5. Watercraft (10) according to claim 4, characterised in that the watercraft (10) has sonar evaluation electronics (220), the sonar evaluation electronics (220) being arranged in the first watertight turret region (170).

6. Watercraft (10) according to one of the preceding claims, characterised in that the propulsion unit has a diesel generator (60) and a traction engine (70), wherein the turret (40) has at least one fresh air supply and one exhaust gas exhaust.

7. Watercraft (10) according to claim 6, characterised in that the exhaust gas exhaust air has a swan neck.

8. Watercraft (10) according to one of the preceding claims, characterised in that at least one first diesel tank (80) is arranged in the water-flooded hull region (230).

9. Watercraft (10) according to claim 8, characterised in that all diesel tanks (80) are arranged in the water-flooded hull region (230), the diesel tanks (80) being arranged either in pairs starboard and port opposite one another or on the longitudinal axis.

10. Watercraft (10) according to one of claims 8 to 9, characterised in that the diesel tanks (80) are designed to be self-compensating.

11. Watercraft (10) according to one of the preceding claims, characterised in that the watercraft (10) has a downwardly extendable keel (20), at least a first group of sonar sensors (30) being arranged in the downwardly extendable keel (20), the extendable keel (20) being extendable by at least 2 m, preferably at least 3 m, particularly preferably at least 5 m, the extendable keel (20) being extendable by at most 15 m, preferably at most 10 m.

12. Watercraft (10) according to one of the preceding claims, characterised in that the turret (40) cuts through the water surface (50) during semi-submerged travel.

13. Watercraft (10) according to one of the preceding claims, characterised in that the watercraft (10) has at least one control cell (140) for controlling the draught.

14. Watercraft (10) according to one of the preceding claims, characterised in that the watercraft (10) is an unmanned watercraft (10), wherein the watercraft (10) comprises a first communication device (130), wherein the first communication device (130) is permanently arranged above the water surface (50).

15. Watercraft (10) according to one of the preceding claims, characterised in that the hull (150) has an outer shell (240) made of a fibre-reinforced plastic.