Watercraft

Abstract

The invention relates to a method and a watercraft (1), in particular a glider, having: a hull (2); a main drive (1A), preferably an electric drive, in particular at least one electric rear engine; and an air nozzle unit (3) with a compressor (4), in particular a radial compressor, for generating an air flow, an air supply line (12) which guides the air flow, and an air nozzle (5), which is connected to the compressor (4) via the air supply line (12), for bringing the air flow to the exterior of the hull (2), wherein a flat nozzle (6A) is provided as the air nozzle (5), which extends, in plan view, outwards from the central region of the hull (2) and preferably rearwards as well, and the flat nozzle (6A) has an elongated air outlet gap (9) at the rear end for discharging the air flow. The flat nozzle also has a water separation edge (12) at the rear end so that an air film can be formed along the exterior of the hull (2) behind the elongated air outlet gap (9) of the flat nozzle (6A).

Description

[0001] watercraft

[0002] The invention relates to a watercraft, in particular a glider, comprising: a hull, a main drive, preferably an electric drive, in particular at least one electric rear motor, an air nozzle unit with a compressor, in particular with a radial compressor, for generating an air flow, with an air supply line carrying the air flow and with an air nozzle connected to the compressor via the air supply line for applying the air flow to the outside of the hull.

[0003] Furthermore, the invention relates to a method for moving a watercraft, in particular in planing motion, on a body of water.

[0004] Watercraft, particularly boats, come in two distinct types that differ significantly in terms of their design, operation, and intended uses. Displacement boats are designed to displace water as they move through the water. This means that displacement boats dive into the water and push some of the water sideways to move forward. Displacement boats have a hull that usually has a characteristic hull shape with a V-shaped hull. This hull shape provides stability and good seakeeping; however, the maximum speed of displacement boats is limited to the hull speed. Displacement boats are used for things like cruise ships, cargo ships, and sailboats where speed is not crucial.In contrast, planing boats are designed to plane on the water as they gain speed, rather than displacing it. Planing boats achieve higher speeds by gliding on the surface of the water rather than submerging in it. The hull of planing boats often has a flat shape, which allows them to use hydrodynamic drag to lift themselves off the water and plane on the surface. Planing boats are generally lighter and have a shallower draft than displacement boats, which increases their speed and maneuverability. Planing boats are often found on pleasure boats and fast workboats, for example those used by the coast guard.

[0005] Plane boats consume a lot of energy because, due to their special design and higher speed, they require more power to glide across the water. The required energy increases exponentially with increasing speed, necessitating powerful motors to operate these boats. This has made the use of electric motors in planing boats unviable so far, because the energy density of the energy storage for the electric motor is too low to allow the planing boat to operate for extended periods.

[0006] In the state of the art, various attempts have also been made to reduce the hull friction of watercraft, since it has already been recognized that at higher speeds the hull friction accounts for the majority of the propulsion power, whereas the water displacement at planing speed only accounts for a fraction of the propulsion power.

[0007] US 3 690 283 A discloses a generic watercraft in which a device is provided for reducing the viscous resistance when a ship's hull moves through a body of water. For this purpose, a device at the bow of the ship's hull is connected to a plate section of the hull via pins and nuts. Compressed air from a compressor can be introduced via an inlet opening into a channel of the device, which is formed between a flat plate section and a cover element. The compressed air then flows through a perforated wall element into a diffuser chamber before the compressed air is blown out through slit-shaped openings. The diffuser chamber is divided by baffles in order to divide it into different pressure ranges. Furthermore, in this prior art, the openings in the perforated wall element are spaced apart from one another at different distances.The distance between the openings is smallest at the bottom, deepest part of the device, where the highest pressure prevails. Thus, US Pat. No. 3,690,283 A merely recognized that the flow conditions can be influenced to a certain extent by the arrangement of the openings.

[0008] However, practice has shown that this adjustment is not sufficient to form a stable gas film along the hull. Tests have shown that the flow film reacts very sensitively to the amount of air. The air film thickness can only be kept stable within a certain range. If too little air is released, the air film can break and water can get to the hull. But too much air is also disadvantageous because it can create turbulence, which is a new source of friction. The air film cannot be adequately regulated solely by changing the distances between the openings in the perforated wall element depending on the depth, as proposed in US 3 690 283 A.

[0009] CN 116 461 642 discloses a device which is intended to reduce the resistance of ships in the water with the aid of air bubbles. The device consists of a first bubble generator and a plurality of second bubble generators. The first bubble generator has a slot-shaped opening and is arranged in the front area of ​​the ship; the plurality of second bubble generators have circular openings and are arranged in the rear area of ​​the ship. In the first bubble generator, rectangular guide walls are attached to a bottom plate of the ship via a supporting structure. Tension and compression rods are attached to the front and rear sides of the rectangular guide walls, by means of which the angle of the rectangular guide walls can be adjusted. In order to prevent further resistance, the lower end of the rectangular guide walls is on the same level as the bottom plate of the hull.Since the air vents are set back in the bow, this bubble generator would be unsuitable for creating an air film. Furthermore, with this state of the art technology, there is no way to adjust the air film to suit current conditions.

[0010] D3 US 5 524 568 A discloses a ship's hull that reduces drag in water using air bubbles. Air can enter through air inlets and is then released through openings on the submerged part of the hull. This creates a film on the hull that reduces drag. The openings are located in grooves extending outward from the keel area. The grooves have an upwardly extending front surface on which the spaced-apart openings are located. Opposite the front surface is an inclined rear surface against which the air exiting the opening flows. This prior art therefore does not offer any possibility of forming an air film along the hull depending on the ambient and operating conditions.

[0011] KR 2022 0160826 A discloses a method for controlling an air lubrication system for ships. A variable frequency drive is used to control a motor of an air compressor. Air is compressed by the air compressor and directed into an air chamber located in the lower part of the ship. The air chamber has a plurality of air outlets through which the air is directed onto the hull, thereby reducing the resistance between the water and the hull. The amount of compressed air supplied to the air chamber is determined using a flow meter. Using this information, the motor speed can be changed to adjust the amount of compressed air.

[0012] This method therefore only allows for centralized control of the amount of air flowing into the air chamber and released from there via the air outlets. However, such centralized control has proven unsuitable in practice for creating an air film along the fuselage, as the varying conditions at the air outlets are not taken into account. In KR 2022 0160826 A, the formation of an air film is not even intended; rather, it merely aims to reduce average friction through bubble formation. However, the energy savings of such a design are very limited, so the use of this device would not be worthwhile, especially for gliders.

[0013] EP 2 123 551 A1 shows a method by which the frictional resistance between the hull of a ship and the water can be reduced by the release of gases. For this purpose, a plurality of gas outlets are arranged on the hull of the ship. In one embodiment, the gas outlets are arranged laterally along a keel line 301. Furthermore, an embodiment of a ship with a flat hull underside is described. One embodiment using a pipe system can also be retrofitted, i.e., installed on ships that are already in operation. In another embodiment, several gas outlets are already taken into account during manufacture of the ship and are thus integrated into the hull. A supply chamber pressurizes air / gas (ambient air or exhaust gases) or a mixture of air and gas in order to transport it via pipes to the gas outlets.Before the gas escapes at the outlets, it can be "vaporized" by a heating device, causing the resulting air bubbles to rise along the hull and along a flow line. The heating device is located on the circumference of each gas outlet. If turbulent flows develop due to higher ship speeds, high and low pressure areas could arise along the hull, where very high frictional resistance occurs. To counteract this phenomenon, the amount of gas escaped at the outlet openings can be controlled. For example, more gas could be released in certain sections to specifically counteract high or low pressure areas a, b. This effect is described for 10 knots (~18.5 km / h) and 15 knots (~27.7 km / h). However, with this known design, only a slight reduction in friction can be achieved. The gas discharge does cause air bubbles to rise along the boat's hull.However, hull friction increases rapidly at high speeds.

[0014] Other designs with air discharge onto a boat hull are described in DE 10 2017 101 055 Al, GB 2508027 A and CN 102897282 A.

[0015] The object of the invention is therefore to alleviate or eliminate at least some of the disadvantages of the invention. This object is achieved by a watercraft according to claim 1 and a method according to claim 12. Preferred embodiments are specified in the dependent claims.

[0016] A flat nozzle is provided as the air nozzle, which is arranged flat against the underside of the fuselage. The flat nozzle extends, in plan view, from a central region of the fuselage outwards, in particular as far as one of the two outer regions of the fuselage, and preferably also extends rearwards. The flat nozzle has an elongated air outlet gap at the rear end for the outlet of the flow of compressed air, referred to below as air flow for short, which is guided from the compressor via the air supply line to the flat nozzle. In addition, the flat nozzle has a water separation edge at the rear end, which is designed so that an air film can be formed along the outside of the fuselage behind the elongated air outlet gap of the flat nozzle.

[0017] Advantageously, by reducing the hull friction of the watercraft, the energy requirement per mile can be significantly reduced. The faster the watercraft is moved through the water, the more advantages there are from the air nozzle unit according to the invention. The watercraft is preferably a planing vessel, in particular a planing boat, preferably a sports or work boat, for example for a coast guard. Due to their use, such watercraft are travelled at planing speed for a large part of their travel time. According to the invention, an air film is built up between the water and the hull. For this purpose, the air nozzle unit has an external energy source in the form of the compressor in order to achieve the required air pressure and the associated delivery rate. In a preferred embodiment, the air pressure is generated by a radial compressor.With the help of this pressure generation, an air flow, preferably with a defined pressure difference and consequently air outlet quantity, can now be emitted from the flat nozzle and guided along the fuselage.

[0018] To form the air film on the underside of the fuselage, the flat nozzle has an elongated air outlet gap, the center line of which preferably runs substantially parallel to the adjacent section of the fuselage. The length of the air outlet gap is many times, preferably at least 5 times, particularly preferably at least 10 times or at least 50 times, in particular at least 100 times or at least 200 times, greater than the height of the air outlet gap perpendicular to the outside of the fuselage.

[0019] In order to distribute the air evenly along the underside of the hull that comes into contact with the water, the air outlet gap is provided in the rear area of ​​the flat nozzle, which also has a water separation edge in the rear area, so that the flat nozzle is designed as a disruptive body. At the water separation edge, the water film is lifted off the watercraft so that a hollow space is created behind the flat nozzle, viewed in the direction of movement of the boat, which hollow space is kept clear by the air flow. The flat nozzle preferably covers an imaginary hull line that is still below the waterline when planing, in particular 50mm to 200mm, for example 150mm, below the waterline. Starting from the central area of ​​the hull, in particular from the keel area of ​​the hull, the air behind the flat nozzle is distributed outwards in line with the planing surface of the watercraft.Advantageously, the air jet unit according to the invention can create a stable layer of air beneath the fuselage, which results in a significantly greater reduction in friction than the prior art described above. Advantageously, the effect becomes even more pronounced with increasing speed.

[0020] Example :

[0021] By lifting the boat hull off the water film, friction can be reduced considerably, in theory by up to a factor of 100. In practice, it has been shown that residual friction remains, for example due to incomplete lifting of the water, partial collapse of the air film or hull surfaces not covered by air. In order to correctly assess this effect, it must be taken into account that from a boat speed of around 20 km / h, hull friction accounts for around 90% of the total propulsion power. Theoretically, this friction power increases with the cube of the boat speed. At a boat speed of 20 km / h, water displacement when planing only accounts for around 10% of the propulsion power. The power for water displacement only increases linearly with boat speed. This means that at higher speeds, hull friction is almost exclusively responsible for the boat's power requirement.In conclusion, it can be assumed that in almost all sports and fast work boats the air jet unit according to the invention reduces the propulsion power, and thus the energy requirement, to up to approx. 10% of the conventional energy requirement. In addition to this energy saving, the oxygen input into the waters navigated is increased. Today, all bodies of water suffer from a notorious lack of oxygen. The invention can therefore have a positive effect in this regard as well. A further advantage is that the reduction in propulsion power enables the use of alternative drives. An electric motor which receives its energy from a battery is therefore particularly preferably provided as the main drive. The watercraft can have a photovoltaic panel to charge the battery.

[0022] For the purposes of this disclosure, the location and direction specifications refer to the intended operating position of the vessel on the body of water. "Forward" means closer to the bow, "aft" means closer to the stern of the vessel. "Inward" and "outward" refer to the vertical plane of symmetry of the hull.

[0023] To accelerate the air flow before exiting the flat nozzle, the flat nozzle, in a preferred embodiment, has an air outlet section that opens into the elongated air outlet gap and tapers toward the rear when viewed in longitudinal section. Furthermore, the tapering of the air outlet section promotes a more uniform exit flow, thereby counteracting any possible collapse of the air film.

[0024] In a preferred embodiment, the flat nozzle has a front section which, viewed in longitudinal section, i.e., relative to a section parallel to the vertical plane of symmetry of the hull, rises rearward. Thus, the flat nozzle rises rearward (i.e., opposite to the direction of travel) along the front section, starting from the front end of the flat nozzle. Preferably, the flat nozzle tapers rearward along the air outlet section to the elongated air outlet gap at the rear end of the flat nozzle. The flattening of the flat nozzle toward the front reduces water resistance.A connecting section can be provided between the front section and the air outlet section, which is preferably connected to the compressor via the air supply line, so that the compressed air flows from the compressor via the air supply line into the connecting section and from there into the air outlet section of the flat nozzle.

[0025] In a preferred embodiment, the elongated air outlet gap directly borders the adjacent section of the exterior of the hull, which is in contact with the water when the air nozzle unit is deactivated. The air outlet gap can be bounded on one side by the exterior of the hull and on the other side by a longitudinal web of the flat nozzle. In this embodiment, the longitudinal web also forms the water separation edge, at which the flowing water separates and is lifted off the exterior of the hull by the air film.

[0026] In a preferred embodiment, the elongated air outlet gap has a height (i.e. an extension perpendicular to the adjacent portion of the fuselage exterior) of 1 to 5 mm, for example substantially 3 mm.

[0027] The length of the air outlet gap depends on the dimensions of the vessel. If the vessel is a boat with a length of 6 to 10 m, the length of the air outlet gap from the inner to the outer end can be 150 to 200 cm.

[0028] Depending on the design, the length of the air outlet gap can be more than 150 cm, but also more than 250 cm, and especially more than 300 cm. The preferred length of the air outlet gap is between 150 cm and 200 cm.

[0029] In a preferred embodiment, the water separation edge extends at a distance of 1 to 5 mm, for example substantially 3 mm, from the adjacent portion of the outside of the hull.

[0030] In order to form an air film on each of the two longitudinal halves of the hull to reduce friction, the air nozzle unit in a preferred embodiment has an adjacent flat nozzle which is located essentially at the same longitudinal position as the flat nozzle in the central region of the hull, in particular in the region of the keel, and extends from there outwards, preferably also to the rear.

[0031] In order to further reduce water friction in a longer watercraft, the air nozzle unit in a preferred embodiment has a rear flat nozzle at a longitudinal distance (i.e. a distance viewed in the direction of the longitudinal axis of the watercraft) behind the flat nozzle, preferably also an adjacent rear flat nozzle at a corresponding longitudinal distance behind the adjacent flat nozzle.

[0032] Depending on the length of the vessel, a central flat nozzle may also be provided, viewed longitudinally, between the flat nozzle and the rear flat nozzle and / or an adjacent central flat nozzle, viewed longitudinally, between the adjacent flat nozzle and the adjacent rear flat nozzle.

[0033] Preferably, the rear or middle flat nozzles described above are constructed in the same way as the front flat nozzles also described above, so that repetitions can be omitted.

[0034] In order to be able to adapt the respective air flows depending on the operation, a control and / or regulating device is provided according to the invention for controlling and / or regulating the respective air flow, in particular the mass flow of the respective air flow, from the elongated air outlet gap of the flat nozzle and at least one further one of the above-mentioned flat nozzles, i.e. the respective air flow from the elongated air outlet gap of the adjacent flat nozzle and / or from the elongated air outlet gap of the rear flat nozzle, and depending on the design also the respective air flow from the elongated air outlet gap of the adjacent rear flat nozzle and / or from the elongated air outlet gap of the middle flat nozzle and / or from the elongated air outlet gap of the adjacent middle flat nozzle.

[0035] The control and regulating device is designed according to the invention for controlling and / or regulating the respective air flow from the respective air outlet gap, in particular the mass flow of the respective air flow, by adjusting flow regulating elements, in particular throttle valves, for regulating the flow of the respective air flow. The respective flow regulating element can be adjusted in order to adapt the flow resistance of the respective air flow before it exits the respective flat nozzle. Since the air nozzle unit has a plurality of the flat nozzles described above, a plurality of flow regulating elements are provided, for example in the respective air supply lines, so that the air flows from the flat nozzles can be individually adjusted. The flow resistances along the air supply lines from the compressor to the air outlet gaps can thus be individually regulated.This advantageously allows for individual adjustment of the individual air streams. Thus, the air streams exiting the individual flat nozzles are regulated individually. Unlike centralized regulation as in the prior art, the air streams can be individually adjusted so that the appropriate amount of air always exits the individual flat nozzles. This advantageously enables the formation of a stable air film.

[0036] Furthermore, the control and regulating device can be designed to control and / or regulate the respective air flow from the respective air outlet gap, in particular the mass flow of the respective air flow, by adjusting the compressor, in particular by adjusting a speed of an impeller of the compressor, in particular of the radial compressor.

[0037] To adapt the air flow exiting the air outlet gap to the operating and ambient conditions, the compressor can be controlled or regulated to increase or decrease the pressure provided by the compressor. If the compressor has an impeller, the air flow, particularly the mass flow rate, can be changed by adjusting the impeller speed.

[0038] In a preferred embodiment, the control and / or regulating device has at least one sensor, preferably at least one sensor per flat nozzle, which preferably continuously detects at least one operating or environmental parameter of the watercraft. The sensor's measurement signal serves as an input variable for controlling or regulating the respective air flow.

[0039] A travel speed sensor, preferably designed for installation in the water, for example a vane anemometer, an impeller or a paddle wheel, can be provided as the sensor for detecting the travel speed of the watercraft. The compressor or the at least one flow regulating element can thus be adjusted depending on the travel speed. For example, the speed of the compressor can be increased and / or the flow resistance can be reduced by means of the flow regulating element when the travel speed of the watercraft increases. Conversely, the speed of the compressor can be reduced and / or the flow resistance can be increased by means of the respective flow regulating element when the travel speed of the watercraft decreases.

[0040] An air mass sensor for detecting an air mass flow from the flat nozzle can also be provided as a sensor. In addition, at least one further air mass sensor can be provided for detecting a further air mass flow from at least one of the further flat nozzles, i.e., the adjacent flat nozzle, the rear flat nozzle, the adjacent rear flat nozzle, the central flat nozzle, and the adjacent central flat nozzle.

[0041] Preferably, one air mass sensor is provided for each flat nozzle. This allows the flow control elements to be adjusted depending on the measured air mass flows from the flat nozzles. This allows the air film to be kept particularly stable. Furthermore, particularly sensitive control is possible.

[0042] The air mass sensor is preferably arranged directly upstream of the respective elongated air outlet gap, as viewed in the direction of air flow. Preferably, all air mass sensors are arranged directly upstream of the respective elongated air outlet gap, as viewed in the direction of air flow.

[0043] An air pressure sensor for detecting an air pressure in the air supply line between the compressor and the flat nozzle can also be provided as a sensor. In addition, at least one further air pressure sensor can be provided in a further air supply line between the compressor and one of the further flat nozzles, i.e. the adjacent flat nozzle, the rear flat nozzle, the adjacent rear flat nozzle, the middle flat nozzle and the adjacent middle flat nozzle. Preferably, further air pressure sensors are provided in all further air supply lines between the compressor and the further flat nozzles. In this way, the compressor or the at least one flow regulating element can be adjusted depending on the measured air pressure in the respective at least one air supply line.

[0044] The use of air mass sensors in conjunction with flow control elements is particularly preferred, as this allows more sensitive control than air pressure to be achieved.

[0045] A water pressure sensor can also be provided as a sensor for detecting the water pressure at the elongated air outlet gap of the flat nozzle. In this embodiment, too, at least one further water pressure sensor can be provided for detecting the water pressure at the elongated air outlet gap of one of the further flat nozzles. Such water pressure sensors are preferably provided at the elongated air outlet gaps of all further flat nozzles. The at least one water pressure sensor is preferably arranged in the central region, in particular in the keel region, of the hull. The water pressure sensor can be used to detect how deep the respective measuring point is below the water surface. The measurement signal from the at least one water pressure sensor can be used to control the compressor or the at least one flow regulation element.In a preferred embodiment, the control and / or regulating device is designed to allow the respective air flow to emerge from the elongated air outlet gap of the flat nozzle and / or the adjacent flat nozzle and / or the rear flat nozzle and / or the adjacent rear flat nozzle and / or the middle flat nozzle and / or the adjacent middle flat nozzle at an exit speed that substantially corresponds to the traveling speed of the watercraft. This makes it possible to reduce hull friction particularly effectively. Particularly preferably, the air mass flows from the flat nozzles are regulated via the flow regulating elements in such a way that the air flows emerge from the elongated air outlet gaps of the flat nozzle and at least one further flat nozzle, i.e.the adjacent flat nozzle and / or the rear flat nozzle and / or the adjacent rear flat nozzle and / or the middle flat nozzle and / or the adjacent middle flat nozzle, preferably all other flat nozzles.

[0046] In a preferred embodiment, the control and / or regulating device is connected to a steering device for steering the watercraft, the regulating device being designed to control or regulate the respective air flow depending on the current position of the steering device. In order to keep the air film on the outside of the hull as stable as possible when cornering, it is advantageous if the regulating device is coupled to the steering device for steering the watercraft. This allows the flat nozzle and the adjacent flat nozzle (and optionally the flat nozzles of the rear or middle nozzle pair) to be controlled differently depending on the position of the steering. This control can take into account the fact that the two longitudinal halves are at different depths in the water depending on the position of the steering, particularly when cornering.

[0047] In a preferred embodiment, the control device is designed to control the flat nozzle and the rear flat nozzle, preferably also the adjacent flat nozzle and the adjacent rear flat nozzle, and particularly preferably also the middle flat nozzle and the adjacent middle flat nozzle, differently depending on the speed of travel. This allows for the fact that the watercraft lifts itself more strongly out of the water with increasing speed, which changes the water pressure at the respective air outlet gaps.

[0048] The compressor preferably has an impeller whose speed is adjustable.

[0049] The preferred compressor is a radial compressor, also called a centrifugal compressor. The radial compressor is a turbo compressor or turbocharger in which the air to be compressed is set in rotation by an impeller running in a specially designed housing and accelerated from the inside out. In the subsequent diffuser, the kinetic energy is converted into pressure. The air flow can be adjusted by changing the speed of the impeller.

[0050] Furthermore, a side channel compressor can be provided as a compressor.

[0051] In a preferred embodiment, an ionizer for ionizing the air flow is arranged upstream of the flat nozzle. Ionizing the air downstream of the compressor allows for a more stable adhesion of the air film to the boat hull.

[0052] The method according to the invention for moving the watercraft comprises at least the following steps:

[0053] Generating an air flow with a compressor and discharging the air flow along the outside of a hull of the vessel,

[0054] Outflow of the air flow from an elongated air outlet gap of a flat nozzle from a central area of ​​the hull to one of the two outer areas of the hull, lifting of the water from the rear end of the flat nozzle,

[0055] Formation of an air film behind the elongated air outlet gap of the flat nozzle between the outside of the hull and the water.

[0056] In a preferred embodiment, the method further comprises the following steps:

[0057] Discharge of an air flow from an adjacent flat nozzle from one central area of ​​the fuselage to the other of the two outer areas of the fuselage,

[0058] Lifting the water from the rear end of the adjacent flat nozzle,

[0059] Formation of an air film behind the adjacent flat nozzle.

[0060] In a preferred embodiment, the method further comprises the steps of:

[0061] Discharge of an air flow from a rear flat nozzle, preferably discharge of an air flow from an adjacent rear flat nozzle,

[0062] Lifting the water from the rear end of the rear flat nozzle, preferably lifting the water from the rear end of the adjacent rear flat nozzle,

[0063] Forming an air film behind the rear flat nozzle, preferably forming an air film behind the adjacent rear flat nozzle.

[0064] In a preferred embodiment, the method further comprises the steps of:

[0065] Regulating the respective air flow, in particular the mass flow of the respective air flow, from the respective air outlet gap of the flat nozzle and / or the adjacent flat nozzle and / or the rear flat nozzle and / or the adjacent rear flat nozzle as a function of at least one operating or environmental parameter of the watercraft, wherein the at least one operating or environmental parameter preferably comprises: the current speed of the watercraft and / or the air pressure in an air supply line between the compressor and the respective flat nozzle and / or the water pressure at a measuring point adjacent to the elongated air outlet gap and / or the position of a steering device of the watercraft.

[0066] In a preferred embodiment, the respective air flow, in particular the mass flow of the respective air flow, is controlled and / or regulated by adjusting the compressor, in particular by adjusting a speed of the compressor, in particular the radial compressor, and / or by flow regulation of the respective air flow.

[0067] The present invention further relates to a watercraft, in particular a glider, according to the following embodiments.

[0068] 1. Watercraft, in particular a glider, comprising: a hull, a main drive, preferably an electric drive, in particular at least one electric rear motor, an air nozzle unit with a compressor, in particular with a radial compressor, for generating an air flow, with an air supply line carrying the air flow and with an air nozzle connected to the compressor via the air supply line for applying the air flow to the outside of the hull, characterized in that a flat nozzle is provided as the air nozzle, which extends outwards, preferably also rearwards, from a central region of the hull when viewed from above, that the flat nozzle has an elongated air outlet gap at the rear end for the outlet of the air flow and that the flat nozzle has a water separation edge at the rear end,so that behind the elongated air outlet gap of the flat nozzle an air film can be formed along the outside of the fuselage.

[0069] 2 . Watercraft according to item 1, characterized in that the flat nozzle ( has an air outlet section ( which opens into the elongated air outlet gap and which, viewed in longitudinal section, is tapered towards the rear.

[0070] 3 . Watercraft according to item 1 or 2, characterized in that the flat nozzle has a front section which rises towards the rear when viewed in longitudinal section.

[0071] 4. Watercraft according to one of points 1 to 3, characterized in that the elongated air outlet gap has a height of 1 to 10 mm, for example substantially 3 mm, and / or a length of 50 cm to 300 cm, wherein the water separation edge preferably extends at a distance of 1 to 10 mm, for example substantially 3 mm, from the outside of the hull (2).

[0072] 5. Watercraft according to one of points 1 to 4, characterized in that the air nozzle unit further comprises: an adjacent flat nozzle which starts at substantially the same longitudinal position as the flat nozzle in the central region of the hull and extends from there outwards, preferably also to the rear, and / or a rear flat nozzle at a longitudinal distance behind the flat nozzle and / or an adjacent rear flat nozzle at a corresponding longitudinal distance behind the adjacent flat nozzle, preferably also a middle flat nozzle seen in the longitudinal direction between the flat nozzle and the rear flat nozzle and / or an adjacent middle flat nozzle seen in the longitudinal direction between the adjacent flat nozzle and the adjacent rear flat nozzle.

[0073] 6. Vessel according to point 5, characterized in that a control and / or regulating device is provided for controlling and / or regulating the respective air flow, in particular the mass flow of the respective air flow, from the elongated air outlet gap of the flat nozzle and / or the adjacent flat nozzle and / or the rear flat nozzle and / or the adjacent rear flat nozzle and / or the middle flat nozzle and / or the adjacent middle flat nozzle.

[0074] 7. Vessel according to point 6, characterized in that the control and regulating device is designed to control and / or regulate the respective air flow, in particular the mass flow of the respective air flow, by adjusting the compressor, in particular by adjusting a speed of an impeller of the compressor, in particular of the radial compressor, and / or by adjusting a flow regulating element, in particular a throttle valve, for flow regulation of the respective air flow.

[0075] 8. Watercraft according to point 6 or 7, characterized in that the control and / or regulating device (19) has: a driving speed sensor for detecting the driving speed of the watercraft and / or an air pressure sensor for detecting an air pressure in the air supply line between the compressor and the flat nozzle, preferably at least one further air pressure sensor in a further air supply line between the compressor and the adjacent flat nozzle or the rear flat nozzle or the adjacent rear flat nozzle or the middle flat nozzle or the adjacent middle flat nozzle, and / or at least one water pressure sensor for detecting the water pressure at the elongated air outlet gap of the flat nozzle, preferably at least one further water pressure sensor for detecting the water pressure at the elongated air outlet gap of the adjacent flat nozzle or the rear flat nozzle orthe adjacent rear flat nozzle or the middle flat nozzle or the adjacent middle flat nozzle. 9. Watercraft (1) according to one of points 6 to 8, characterized in that the control and / or regulating device is designed to allow the respective air flow to exit the elongated air outlet gap of the flat nozzle and / or the adjacent flat nozzle and / or the rear flat nozzle and / or the adjacent rear flat nozzle and / or the middle flat nozzle and / or the adjacent middle flat nozzle at an exit speed that substantially corresponds to the traveling speed of the watercraft.

[0076] 10. Watercraft (1) according to one of items 6 to 9, characterized in that the control and / or regulating device is connected to a steering device for steering the watercraft, wherein the regulating device is designed to control or regulate the respective air flow depending on a current position of the steering device.

[0077] 11. Method for moving a watercraft (1), preferably according to one of the items 1 to 10, in particular in planing motion, on a body of water, comprising the steps:

[0078] Generating an air flow with a compressor, in particular with a radial compressor, and discharging the air flow along the outside of a hull of the watercraft, characterized by discharging the air flow from an elongated air outlet gap of a flat nozzle from a central region of the hull to one of the two outer regions of the hull,

[0079] Lifting of the water from the rear end of the flat nozzle , forming an air film behind the elongated air outlet gap of the flat nozzle between the outside of the hull and the water .

[0080] 12 . Procedure according to point 11 , characterized by :

[0081] Discharge of an air stream from an adjacent flat nozzle from one central area of ​​the hull to the other of the two outer areas of the hull, lifting of the water from the rear end of the adjacent

[0082] Flat nozzle,

[0083] Formation of an air film behind the adjacent flat nozzle between the outside of the hull and the water.

[0084] 13 . Procedure according to item 11 or 12 , characterized by :

[0085] Discharge of an air flow from a rear flat nozzle, preferably discharge of an air flow from an adjacent rear flat nozzle,

[0086] Lifting the water from the rear end of the rear flat nozzle, preferably lifting the water from the rear end of the adjacent rear flat nozzle,

[0087] Forming an air film behind the rear flat nozzle, preferably forming an air film behind the adjacent rear flat nozzle.

[0088] 14 . Method according to one of the items 11 to 13 , characterized by :

[0089] Regulating the respective air flow, in particular the mass flow of the respective air flow, from the flat nozzle and / or from the adjacent flat nozzle and / or from the rear flat nozzle and / or from the adjacent rear flat nozzle depending on at least one operating or environmental parameter of the watercraft, wherein the at least one operating or environmental parameter preferably comprises: the current speed of the watercraft and / or the current water pressure at a measuring point adjacent to the elongated air outlet gap and / or the current position of a steering device of the watercraft.

[0090] 15. Method according to one of points 11 to 14, characterized in that the respective air flow, in particular the mass flow of the respective air flow, is controlled and / or regulated by adjusting the compressor, in particular by adjusting a speed of the radial compressor, and / or by flow regulation of the respective air flow.

[0091] The invention is further explained below with reference to an embodiment shown in the drawings.

[0092] Fig. 1 shows a rear view of a watercraft according to the invention.

[0093] Fig. 2 shows a sectional view of the vessel along the line AA in Fig. 1.

[0094] Fig. 3 shows a sectional view of the vessel along the line BB in Fig. 1

[0095] Fig. 4 shows a bottom view of the vessel in the direction of arrow D in Fig. 1.

[0096] Fig. 5 shows a sectional view of the vessel along the line FF in Fig. 4.

[0097] Fig. 6 shows detail E in Fig. 3.

[0098] Fig. 7 shows detail G in Fig. 5.

[0099] Fig. 8 shows a sectional view along a flat nozzle, which is arranged on the underside of the hull of the watercraft.

[0100] Fig. 9 shows a detail of Fig. 8.

[0101] Fig. 10 shows a side view of the flat nozzle from Fig. 8, so that an elongated air outlet gap of the flat nozzle is visible.

[0102] Fig. 11 shows a block diagram of a control device of the watercraft of Figs. 1 to 10.

[0103] Fig. 12 shows a diagram of a further embodiment of the control device of the watercraft of Figs. 1 to 10. Figs. 1 to 5 show a watercraft 1, which in the embodiment shown is a planing vessel, in this case a planing boat. The planing boat has a hull 2 ​​in planing shape. This means that the hull 2 ​​is shaped so that the planing boat lifts itself out of the water with increasing speed and glides on it. The planing boat can thus transition from a displacement mode to a planing mode. The planing boat has a main drive 1A (symbolically shown in Fig. 3), which is preferably an electric motor. The electric motor can be arranged at the stern of the watercraft 1. The main drive can be designed in any desired way (not shown).

[0104] As can be seen from Figs. 1 to 5, the watercraft 1 also has an air nozzle unit 3 with at least one compressor 4 (symbolically shown in Fig. 3), which is in fluid communication with an arrangement of air nozzles 5. The compressor 4, which is in particular a radial compressor, generates a compressed air flow, hereinafter referred to as air flow, which is discharged via the individual air nozzles 5 along the underside of the hull 2.

[0105] As can also be seen from Figs. 1 to 5, the arrangement of air nozzles 5 comprises a flat nozzle 6A and an adjacent flat nozzle 6B, which, as seen in plan view (i.e., a bottom view of the ship's hull), each extend from a central region of the hull 2, here from a keel 2A, outwards (i.e., toward the respective longitudinal side of the hull 2) and rearwards (i.e., toward the stern). The flat nozzle 6A and the adjacent flat nozzle 6B form a front nozzle pair, which is arranged closer to the bow than to the stern of the watercraft 1.

[0106] In addition, the air nozzle unit 3 in the example shown has a rear flat nozzle 7A and an adjacent rear flat nozzle 7B, which also extend outwards and rearwards from the central region of the hull 2, here again from the keel 2A. The rear flat nozzle 7A and the adjacent rear flat nozzle 7B form a rear nozzle pair, which is arranged closer to the stern than to the bow of the watercraft 1. Finally, the air nozzle unit 3 in the example shown has a middle flat nozzle 8A and an adjacent middle flat nozzle 8B, which also extend outwards and rearwards from the central region of the hull 2, here from the keel 2A. The middle flat nozzle 8A and the adjacent middle flat nozzle 8B form a middle nozzle pair, which, viewed in the longitudinal direction of the watercraft 1, is located between the front and rear nozzle pairs.

[0107] Depending on the length of the watercraft 1, the arrangement of air nozzles 5 can alternatively comprise just a single nozzle pair, exactly two nozzle pairs, or even more than the three nozzle pairs shown. The flat nozzles of each nozzle pair are each identically designed and arranged in a mirror image with respect to a vertical center plane of the watercraft 1. If reference is made below to the flat nozzle 6A, these statements apply accordingly to the other flat nozzles. The flat nozzle 6A has a flattened shape, with which the flat nozzle 6A nestles against the hull 2.

[0108] As can be seen from Fig. 10, the flat nozzle 6A has an elongated air outlet gap 9 at the rear end, through which the air flow is jetted out to the rear. The air outlet gap 9 extends essentially over the entire length of the flat nozzle 6A from an end near the keel to an end far from the keel. In addition, the flat nozzle 6A has a water separation edge 10 at the rear end, at which the water is spaced apart from the hull 2 ​​by the air flow from the air outlet gap 9. For this purpose, the air flow behind the elongated air outlet gap 9 of the flat nozzle 6A forms an air film, i.e. a flat air layer, along the outside of the hull 2, which separates the hull 2 ​​from the water behind the flat nozzle 6A.

[0109] Fig. 8 shows a longitudinal section through the flat nozzle 6A parallel to the vertical center plane of the watercraft 1. Accordingly, the compressed air from the compressor 4 is guided via an air supply line 12 in the direction of the flat nozzle 6A. Further air supply lines 12 (not shown) lead to the other flat nozzles. The compressed air is conveyed by means of a connecting part 13 through the hull 2 ​​into the flat nozzle 6A. The compressed air is then distributed laterally over the length of the flat nozzle 6A and flows rearwardly through the elongated air outlet gap 9 out of the flat nozzle 6A. A check valve to prevent water from entering can be provided in the air supply line 12 or in the flat nozzle 6A (not shown).

[0110] As can be seen from Fig. 8, the flat nozzle 6A has an air outlet section 14 which opens into the elongated air outlet gap 9 and which tapers towards the rear when viewed in longitudinal section. In addition, the flat nozzle 6A has a front section 15 which rises towards the rear when viewed in longitudinal section. The front section 15 is connected to the air outlet section 14 via a connecting section 16. The connecting part 13, via which the compressed air is introduced into the flat nozzle 6A, opens into the connecting section 16.

[0111] As can be seen from Fig. 8, the elongated air outlet gap 9 directly adjoins the outside of the hull 2. In the example shown, the elongated air outlet gap 9 has a height of, for example, substantially 3 mm. The length of the air outlet gap 9 from the end near the keel to the end far from the keel is, for example, substantially 200 cm. In the example shown, the water separation edge 10 runs at a distance of, for example, substantially 3 mm from the outside of the hull 2.

[0112] As can be seen from Fig. 8, the flat nozzle 6A in the example shown is designed as an attachment cap, which is attached to the hull 2 ​​of the watercraft 1 via fastening elements 17. Alternatively, the flat nozzle 6A can also be formed integrally with the hull 2.

[0113] As can be seen schematically in Fig. 11, the watercraft 1 has a control device 19 with which the individual air flows of the air nozzle unit 3 can be controlled. The control device 19 has a controller 20 which is connected to at least one sensor for detecting at least one operating or environmental parameter. In the example shown, several sensors are provided for detecting various operating and environmental parameters. Depending on the design, only one of these sensors or a selection of these sensors can be provided. The controller 20 can be connected to a travel speed sensor 21 for detecting the travel speed of the watercraft 1. Furthermore, the controller 20 can be connected to an arrangement of air mass sensors 22 with which the respective air mass flow from the respective flat nozzle 6A, 6B; 7A, 7B; 8A, 8B is measured.Furthermore, the controller 20 can be connected to an arrangement of air pressure sensors (not shown), each of which measures the air pressure in the respective air supply line 12 between the compressor 4 and the respective flat nozzle 6A, 6B; 7A, 7B; 8A, 8B. In addition, the controller 20 can be connected to an arrangement of water pressure sensors 23, each of which measures the local water pressure adjacent to the respective air outlet gap 9 of the respective flat nozzle 6A, 6B; 7A, 7B; 8A, 8B. The water pressure sensors 23 are preferably located adjacent to the keel-side end of the respective air outlet gap 9. Finally, the controller 20 can be connected to a steering device 24 for steering the watercraft 1, so that the respective air flow can be controlled or regulated depending on the current position of the steering device. This allows, for example, cornering to be taken into account during the control process.

[0114] The various sensors supply the input signals for the controller 20, which uses the input signals from the sensors to create corresponding control signals for adjusting the individual air flows from the air outlet gaps. For this purpose, the controller 20 is connected on the one hand to the compressor 4, so that the air pressure provided by the compressor 4 can be adjusted. If the compressor 4 is a radial compressor or a side channel compressor, the controller 20 can regulate the speed of the compressor in order to adjust the pressure ratio compared to the ambient pressure. In the example shown, the controller 20 is additionally or alternatively connected to an arrangement of flow regulating elements 25, in particular throttle valves, for regulating the flow of the respective air flow, i.e. for influencing the flow resistance, in the respective air supply line 12.

[0115] With the control device 19, the respective air flow can be jetted out of the flat nozzles 6A, 6B; 7A, 7B; 8A, 8B at an exit speed that essentially corresponds to the speed of the watercraft 1. Furthermore, the current immersion depth of the respective flat nozzle 6A, 6B; 7A, 7B; 8A, 8B into the water can be taken into account. The nozzle pairs can have different immersion depths due to their different longitudinal positions on the hull 2. Furthermore, the immersion depth changes due to the speed of the watercraft 1. Finally, the immersion depths of the two flat nozzles of each nozzle pair can constantly change relative to one another because the watercraft 1 is subject to fluctuations or is cornering.By continuously controlling the compressor 4 and the flow control elements 25 depending on the input signals from the sensors, the air films behind the flat nozzles 6A, 6B; 7A, 7B; 8A, 8B can be reliably maintained.

[0116] Fig. 12 shows schematically a further embodiment of the control device 19.

[0117] The control device 19, in turn, has the controller 20, which acts as the central control. The controller 20 is connected to the following sensors:

[0118] The air mass sensors 22 detect the air mass flows which are sprayed out of the flat nozzles 6A, 6B; 7A, 7B; 8A, 8B.

[0119] The speed sensor 21 detects the speed of the watercraft 1. The water pressure sensors 23 detect the respective water pressure at the elongated air outlet gaps 9 of the flat nozzles 6A, 6B; 7A, 7B; 8A, 8B.

[0120] An optional air pressure sensor 24 measures the air pressure downstream of the compressor 4. In the example shown, a silencer 26 is provided for the compressor 4.

[0121] The signals of these sensors are processed by the controller 20 into control signals with which the flow regulation elements 25 are adjusted so that the air mass flows specified by the controller 20 are discharged from the individual flat nozzles 6A, 6B; 7A, 7B; 8A, 8B.

[0122] In addition, the regulator 20 can be connected to the compressor 4 in order to regulate the air pressure provided by the compressor 4.

Claims

Claims:

1. Watercraft (1), in particular a glider, comprising: a hull (2), a main drive (1A), preferably an electric drive, in particular at least one electric rear motor, an air nozzle unit (3) with a compressor (4), in particular with a radial compressor, for generating an air flow, with an air supply line (12) carrying the air flow and with an air nozzle (5) connected to the compressor (4) via the air supply line (12) for applying the air flow to the outside of the hull (2), wherein a flat nozzle (6A) is provided as the air nozzle (5), which extends outwards, preferably also rearwards, from a central region of the hull (2) as seen in plan view, wherein the flat nozzle (6A) has an elongated air outlet gap (9) at the rear end for the outlet of the air flow and wherein the flat nozzle (6A) has a water separation edge at the rear end (12),so that behind the elongated air outlet gap (9) of the flat nozzle (6A) an air film can be formed along the outside of the fuselage (2), characterized in that the air nozzle unit (3) further comprises: an adjacent flat nozzle (6B), which is located essentially at the same longitudinal position as the flat nozzle (6A) in the central region of the fuselage (2) and extends from there outwards, preferably also rearwards, and / or a rear flat nozzle (7A) at a longitudinal distance behind the flat nozzle (6A), wherein a control and / or regulating device (19) is provided for controlling and / or regulating the respective air flow, in particular the mass flow of the respective air flow, from the elongated air outlet gap (9) of the flat nozzle (6A) and the adjacent flat nozzle (6B) and / or the rear flat nozzle (8A), wherein the control and regulating device (19) is provided for controlling and / or regulating the respective air flow, in particular of, Mass flow of the respective air flow, by adjusting flow regulating elements (25), in particular throttle valves, for flow regulation of the respective air flow from the elongated air outlet gap (9) of the flat nozzle (6A) and the adjacent flat nozzle (6B) or the rear flat nozzle (8A).

2. Watercraft (1) according to claim 1, characterized in that the flat nozzle (6A) has an air outlet section (14) which opens into the elongated air outlet gap (12) and which, viewed in longitudinal section, is tapered towards the rear.

3. Watercraft (1) according to claim 1 or 2, characterized in that the flat nozzle (6A) has a front section (15) which rises rearward when viewed in longitudinal section.

4. Watercraft (1) according to one of claims 1 to 3, characterized in that the elongated air outlet gap (12) has a height of 1 to 10 mm, for example substantially 3 mm, and / or a length of 50 cm to 300 cm, wherein the water separation edge (12) preferably extends at a distance of 1 to 10 mm, for example substantially 3 mm, from the outside of the hull (2).

5. Watercraft (1) according to one of claims 1 to 4, characterized in that the air nozzle unit (3) further comprises: an adjacent rear flat nozzle (7B) at a corresponding longitudinal distance behind the adjacent flat nozzle (6B), preferably also a middle flat nozzle (8A) seen in the longitudinal direction between the flat nozzle (6A) and the rear flat nozzle (7A) and / or an adjacent middle flat nozzle (8B) seen in the longitudinal direction between the adjacent flat nozzle (6B) and the adjacent rear flat nozzle (7B).

6. Watercraft (1) according to one of claims 1 to 5, characterized in that the control and / or regulating device (19) is provided for controlling and / or regulating the respective air flow, in particular the mass flow of the respective air flow, from the elongated air outlet gap (9) of the adjacent rear flat nozzle (8B) and / or the middle flat nozzle (8A) and / or the adjacent middle flat nozzle (8B).

7. Watercraft (1) according to one of claims 1 to 6, characterized in that the control and / or regulating device (19) has: an air mass sensor (22) for detecting an air mass flow from the flat nozzle (6) and at least one further air mass sensor (22) for detecting an air mass flow from the adjacent flat nozzle (6B) or from the rear flat nozzle (7A), preferably at least one further air mass sensor (22) for detecting an air mass flow from the adjacent rear flat nozzle (7B) or from the middle flat nozzle (8A) or from the adjacent middle flat nozzle (8B).

8. Watercraft (1) according to one of claims 1 to 7, characterized in that the control and / or regulating device (19) comprises: a travel speed sensor (21) for detecting the travel speed of the watercraft (1).

9. Watercraft (1) according to one of claims 1 to 8, characterized in that the control and / or regulating device (19) has: at least one water pressure sensor (23) for detecting the water pressure at the elongated air outlet gap (9) of the flat nozzle (6a), preferably at least one further water pressure sensor (23) for detecting the water pressure at the elongated air outlet gap (9) of the adjacent flat nozzle (6B) or the rear flat nozzle (8A) or the adjacent rear flat nozzle (8B) or the middle flat nozzle (8A) or the adjacent middle flat nozzle (8B).

10. Watercraft (1) according to one of claims 1 to 9, characterized in that the control and / or regulating device (19) is designed to allow the respective air flow to exit the elongated air outlet gap (9) of the flat nozzle (6A) and / or the adjacent flat nozzle (6B) and / or the rear flat nozzle (8A) and / or the adjacent rear flat nozzle (8B) and / or the middle flat nozzle (8A) and / or the adjacent middle flat nozzle (8B) at an exit speed that substantially corresponds to the traveling speed of the watercraft (1).

11. Watercraft (1) according to one of claims 1 to 10, characterized in that the control and / or regulating device (19) is connected to a steering device (24) for steering the watercraft (1), wherein the regulating device (19) is designed to control or regulate the respective air flow depending on a current position of the steering device (24).

12. Method for moving a watercraft (1), preferably according to one of claims 1 to 11, in particular in planing motion, on a body of water, comprising the steps: Generating an air flow with a compressor (4), in particular with a radial compressor, and discharging the air flow along the outside of a hull (2) of the watercraft (1), Outflow of the air flow from an elongated air outlet gap (12) of a flat nozzle (6A) from a central region of the fuselage (2) to one of the two outer regions of the fuselage (2), Outflow of an air flow from an adjacent flat nozzle (6B) from a central region of the fuselage (2) to the other of the two outer regions of the fuselage and / or outflow of an air flow from a rear flat nozzle (7A), Lifting the water from the rear end of the flat nozzle (6A) and lifting the water from the rear end of the adjacent flat nozzle (6B) or the rear flat nozzle (7A), Forming an air film behind the elongated air outlet gap (12) of the flat nozzle (6A) and the adjacent flat nozzle (6B) or the rear flat nozzle (7A) between the outside of the hull (2) and the water, characterized by regulating the respective air flow, in particular the mass flow of the respective air flow, from the flat nozzle (6A) and from the adjacent flat nozzle (6B) or from the rear flat nozzle (7A) by flow regulation of the respective air flow.

13. Method according to claim 12, characterized by: Outflow of an air flow from a rear flat nozzle (7A), Discharge of an air flow from an adjacent rear flat nozzle (7B), Lifting the water from the rear end of the adjacent rear flat nozzle (7B) , Formation of an air film behind the adjacent rear flat nozzle (7B) .

14. Method according to claim 12 or 13, characterized by: Regulating the respective air flow, in particular the mass flow of the respective air flow, from the flat nozzle (6A) and / or from the adjacent flat nozzle (6B) and / or from the rear flat nozzle (7A) and / or from the adjacent rear flat nozzle (7B) depending on at least one operating or environmental parameter of the watercraft (1), wherein the at least one operating or environmental parameter preferably comprises: the current travel speed of the watercraft (1) and / or the current water pressure at a measuring point adjacent to the elongated air outlet gap (9) and / or the current position of a steering device (24) of the watercraft (1).

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