Ship for subsea survey and method for acquiring subsea survey data

Abstract

A sustainable method and environmentally friendly device for improving survey data acquisition is achieved by providing a vessel for subsea survey, at least one lift hydrofoil (10), a method of acquiring subsea survey data, a method of producing the vessel and the use of the vessel. The invention also relates to the improvement of sustainable development and environmental development, and we jointly create a safe and livable world.

Description

Technical Field

[0001] The present disclosure generally relates to a vessel for seafloor surveying, and more particularly to at least one lifting hydrofoil for use with a vessel for seafloor surveying, a method of acquiring seafloor survey data, a method of producing a vessel, and uses of the vessel. In gaining insights from geographic data, the present invention also relates to improvements in sustainable and environmental development: together we create a safe and livable world. Background Art

[0002] There is a general and ongoing need to improve the quality and speed of seafloor surveys. In seafloor surveys, at least one sensor is disposed beneath the surface of a body of water, such as an ocean, river, or lake. These sensors are disposed to capture survey data related to characteristics of the seafloor environment. For example, the survey data may be related to the geometry of the seafloor, but is not limited thereto and may also be used to detect, for example, boulders, and to map the seafloor for various seafloor operations. The survey data may also be related to the detection of subsurface objects buried beneath the seafloor, such as pipelines, unexploded ordnance (such as mines), and the like. In addition, the survey data may be related to the type of soil beneath the seafloor, which may be relevant to preliminary surveys of projects such as wind farm foundations.

[0003] In the process of acquiring seafloor survey data, it is often necessary to place sensors below the water surface so that the sensors can detect features associated with the seafloor environment. Different types of sensors have different types of requirements and limitations. Sensors towed behind a vessel or attached to the hull of a vessel often encounter issues such as unstable conditions, which can limit the data quality. For example, noise generated by the interaction between the hull and the water can affect the data quality. Vibrations generated by the propulsion of the ship can affect the sensors. The movement of the ship through the water can cause water to be entrained around the hull of the ship, that is, water mixed with air, which has a great impact on the acquisition of data from the sensors. In addition, the water passing over the hull forms a turbulent boundary layer, whose random vortices can also negatively affect the quality of the data acquired by the sensor.

[0004] It is known that the quality of data acquisition decreases with increasing speed, which also affects the quality of sensor data, as the increased water speed relative to the vessel's hull generates more ambient noise. Roughness on the vessel's surface causes additional turbulence in the boundary layer of the water flow, which also affects signal quality. Another issue associated with increased flow speed is increased drag, which limits the efficiency of the vessel. Since surveys often take long periods of time and may be in remote areas, the propulsion efficiency of the vessel is very important.

[0005] There is an ongoing effort to improve data quality and data acquisition efficiency while minimizing energy consumption. It is known to introduce sensors in a gondola below the hull of a vessel. A gondola is a structure located below the waterline of the vessel, positioned at a distance from the hull of the vessel, with its depth set so as to minimize disturbances such as waves. The stability of the sensors in a gondola is higher than the stability of the sensors in the hull of the vessel. For example, since the gondola does not break the waterline, there are fewer problems associated with entrained water and highly random turbulent boundary layers, which can affect data quality.

[0006] However, placing sensors in a gondola brings additional constraints such as increased drag, reduced efficiency, increased weight, and increased draft.

[0007] It is known that hydrofoils can increase the efficiency of a ship. The ship is provided with a hydrofoil system so that when the ship reaches a certain speed, the ship is lifted out of the water due to the lifting force of the hydrofoils. However, using gondolas to store sensors or setting sensors in the hull of the ship is incompatible with the use of hydrofoils. When the ship is lifted out of the water, the sensors are also lifted with it. The sensors may be lifted completely out of the water, or to some extent they are set in a less stable area, closer to the waterline of the ship. For example, if the sensors are not set at a deep enough depth, the waves may cause serious interference with the sensor data. In addition, the increase in speed required for the ship to gain lift results in a greater drag on the gondola, which greatly reduces efficiency. The gondolas greatly increase the drag and introduce instability to the sensors, which reduces the data quality. In addition, the gondolas must be more robust to withstand this increased drag, which further increases the propulsion requirements and reduces efficiency.

[0008] Therefore, known seafloor surveying techniques do not provide a solution that can obtain high-quality data while minimizing energy consumption.

[0009] An improved seabed survey vessel and method for acquiring seabed survey data are needed to solve the above problems. Summary of the invention

[0010] In one aspect of the invention, a vessel for seabed surveying is provided. The vessel comprises a hull. The vessel further comprises at least one lifting hydrofoil. The vessel comprises a connection structure for connecting the at least one lifting hydrofoil to the hull. The connection structure is arranged to convert the lifting force from the at least one lifting hydrofoil to the hull of the vessel. The at least one lifting hydrofoil comprises at least one survey sensor. By providing the vessel with at least one lifting hydrofoil, the efficiency of the vessel is improved. By providing at least one survey sensor in the lifting hydrofoil, the stability of the sensor is improved, thereby improving the data quality.

[0011] Sensor stability refers to the consistency of the data generated while the environmental characteristics remain unchanged. The stability of at least one survey sensor depends, among other things, on its interaction with the water flowing through the sensor. For example, entrained water, formed by the mixing of air with water, can severely affect the stability of the sensor due to its randomness and high energy density. In other words, entrained water carries kinetic energy, which can produce a strongly random response in the sensor. In addition, the noise generated by the interaction of the hull with the water can also negatively affect the results of sound-based sensors. The formation of a turbulent boundary layer can also produce a random response in the sensor, as eddies form around the sensor, which can affect the data quality and sensor stability. A turbulent boundary layer forms on a surface when water flows over a certain length of the surface. Initially, the boundary layer is laminar, and as the water velocity increases, the velocity profile between the surface and the water decreases and the laminar flow in the boundary layer transitions to turbulent flow. This turbulent boundary layer is random and can negatively affect the sensor if the sensor is located beyond the transition point between laminar and turbulent flow.

[0012] Lifting hydrofoils have not been used in the survey process because the vessel's hull and / or the gondola containing the sensors would be lifted out of the water, or close to the surface. This would significantly reduce sensor stability and result in survey data that does not meet quality requirements.

[0013] However, the present invention solves these disadvantages by positioning at least one survey sensor in a lifting hydrofoil. The expression "at least one survey sensor is positioned in a lifting hydrofoil" is to be understood as being placed in the hydrofoil, or being located at the surface of the hydrofoil so that the survey sensor forms part of the outer surface of the lifting hydrofoil, or being located in the body of the hydrofoil, depending on the type of survey sensor used. When the hull of the vessel is raised closer to or away from the water surface, the lifting hydrofoil is still underwater. The lifting hydrofoil in the present invention is also located in the water, farther from the water surface (deeper in the water), so that disturbances such as waves have less impact on the sensor. In addition, since the lifting hydrofoil is positioned away from the water surface, the impact of entrained water on the stability of the sensor is also reduced. In addition, since the lifting hydrofoil is arranged to lift the hull of the vessel and reduce its wetted surface, the total noise generated by the interaction of the hull with the water is further reduced, thereby improving the measurement results. Since the lifting hydrofoil usually has a relatively low length and a high width, the lifting hydrofoil has a relatively high proportion of the surface area where the boundary layer is laminar. In some embodiments, the flow over the lifting hydrofoil may even be completely laminar. This further improves the data quality of the sensor.

[0014] The motion of a vessel through the water can result in entrained water, i.e. water mixed with air, around the hull of the vessel, which can have a significant impact on the data acquired from the sensors. Additionally, water moving past the hull forms a turbulent boundary layer, the random eddies of which can also negatively impact the quality of data acquired by the sensors.

[0015] The efficiency of the vessel is thus improved by reducing the drag of the vessel and improving energy consumption. The drag of the vessel is reduced by reducing the frictional drag of the hull and optionally removing the gondola from the hull of the vessel. The improvement in energy efficiency helps to create a more sustainable vessel for seabed surveying, which is more environmentally friendly than traditional survey vessels.

[0016] The vessel can be any buoyant or semi-buoyant structure that is arranged to move relative to the seabed, such as a ship, a boat, a barge, a submarine, etc. The hull of the vessel is any outer surface of the vessel, including but not limited to the wetted surface below the waterline, the outer surface above the waterline, or for example the deck, etc. The wetted surface of the hull is the surface of the hull in contact with the water. The connection structure provides a connection between the hull and the lifting hydrofoil. This connection can be a direct connection or an indirect connection. For example, the connection structure can directly connect the lifting hydrofoil to the bottom side of the hull, or to the side of the hull above the waterline, for example. The connection can also be formed by a structure on the deck of the vessel, for example, by being pivotally attached to the lateral hydrofoil on the deck via, for example, a mounting structure. Alternatively or additionally, the hydrofoil can also be connected to a structure above the deck, such as a crane or a frame. This indirect connection structure is also arranged to convert the lifting force from the lifting hydrofoil to the hull of the vessel.

[0017] When a vessel is stationary, the force of gravity applied to the vessel is balanced by the force applied to the water by the displacement of the water, thereby creating buoyancy. This buoyancy is related to the wetted surface of the vessel's hull, because the wetted surface, together with the shape of the hull, dictates the amount of water displacement that causes buoyancy. The problem associated with this wetted surface is that when the vessel is moving, the wetted surface also provides friction in the form of, for example, frontal drag and frictional drag.

[0018] As the vessel moves, the lifting hydrofoils generate a lift that reduces the required buoyancy. In equilibrium, the buoyancy of the wetted surface and the lifting force of the lifting hydrofoils equal the weight on the vessel. With the hull fully lifted out of the water, the lifting force of the hydrofoils is substantially equal to the weight on the vessel, and the buoyancy is substantially zero. Thus, the lifting hydrofoils of the present disclosure are arranged to reduce the wetted surface of the vessel.

[0019] The connection structure may be integrally formed with the hull and the lifting foil. In such an embodiment, the hull is formed so that the connection structure is integrally formed, rather than being attached at a later stage, such as by welding or modular connection. The connection structure may also be integrally formed with the lifting foil.

[0020] In one embodiment, the connection structure can also be used to provide a data transmission and / or power transmission channel to power one or more sensors and transmit data collected from the sensors. In an alternative or additional embodiment, the lifting hydrofoil can include a power supply and / or a data storage unit, such as a hard drive, to store survey data after collecting data from the environment.

[0021] The lifting hydrofoil is arranged to provide lifting force to the hull of the ship through a connecting structure. The lifting hydrofoil can be any lifting body, surface or wing arranged to operate in water. The lifting force is generated by the pressure difference between the upper surface and the lower surface of the lifting hydrofoil. The pressure difference is usually generated by the curvature or shape on the upper and lower surfaces of the hydrofoil. The water flow difference on the upper and lower surfaces of the hydrofoil will produce a pressure difference, so that the pressure on the upper surface of the wing is lower than the pressure on the lower surface of the wing, thereby generating an upward net pressure. This upward net pressure and the area over which this pressure acts on the lifting wing will generate lifting force, thereby reducing the wetted surface of the ship, and therefore reducing its frontal drag and friction drag, thereby improving the efficiency of the ship.

[0022] In a preferred embodiment, the vessel comprises a plurality of lifting hydrofoils. The vessel may comprise more than two lifting hydrofoils. The vessel may comprise more than four lifting hydrofoils. The vessel may comprise more than six lifting hydrofoils. The plurality of lifting hydrofoils may all be connected to the hull of the vessel by a connecting structure. The plurality of lifting hydrofoils may be connected to the hull by a single connecting structure. Alternatively, the plurality of lifting hydrofoils may all have separate connecting structures. In one embodiment, the plurality of lifting hydrofoils are connected to the hull of the vessel by a plurality of connecting structures, such that a single connecting structure may connect one or more of the plurality of lifting hydrofoils to the hull of the vessel.

[0023] A survey sensor is any sensor that provides information about the vessel's environment, i.e. any feature not related to the vessel itself. Survey data is information acquired from a survey sensor. Survey sensors are understood to exclude sensors related to features of the vessel and / or the hydrofoil itself, such as motion sensors, accelerometers, gyro sensors, etc. In the context of the present disclosure, survey sensors only relate to sensors that provide information about the vessel's environment.

[0024] In an embodiment, at least one survey sensor includes at least one sensor from the following group of sensors: sonar systems, such as echo sounders; single beam, beamforming multi-beam, seafloor profiling systems; acoustic Doppler systems; interferometric sonar systems, including side-scan sonar and swath bathymetry systems; laser ranging systems, including lidar and laser stripping and accompanying camera vision technology. In the context of the present disclosure, the term survey sensor is understood to include sonar systems, which include transmitters and / or receivers. In an embodiment, the sensor may include the receiver itself or the transmitter itself.

[0025] By using such survey sensors, ships can be used for oceanographic research and to collect geographic data. In particular, sonar systems generally involve the use of sound propagation to navigate, measure distances, communicate with or detect objects on or under the water surface or even under the seabed. Two types of sonar systems are generally considered. First, passive sonar uses existing propagating waves to measure environmental characteristics, such as detecting seabed characteristics or detecting objects under the seabed, such as pipelines, soil types, pipelines or similar objects. Passive sonar basically uses environmental propagating waves that are not actively generated by the measuring instrument.

[0026] Another type of sonar system is an active system, in which the sensor transmits a pulse or continuous wave train and listens for the reflected propagating waves.Sonar can be used as a means of acoustically locating and measuring the echo signature of "targets" under the seabed in the water, above the water, or in the seabed soil.

[0027] An echo sounder is a system that uses sonar for ranging, commonly used to infer water depth and map the seabed, also known as sounding. Sound waves are transmitted into the water, and then the time of flight between transmission and reception of the returned signal is measured. By utilizing information related to the speed of sound in water, the total depth can be derived from the time of flight between transmission and reception of the signal. A single-beam echo sounder determines the depth at a given location based on the propagation time of a short sonar pulse. A multi-beam echo sounder uses a fan-shaped signal array to provide information in two dimensions, namely the seabed height along a line. The fan is advantageously extended transversely to the direction of motion of the surface vessel, thereby mapping the three-dimensional seabed and providing two-dimensional (x, y) information about the seabed height (z), i.e., water depth. To extract direction information from the returned propagated waves, a multi-beam echo sounder uses beamforming or spatial filtering to determine the time of flight of the directionally-signaled transmission. This is advantageously achieved by combining the elements in the antenna array such that signals at a particular angle are subject to constructive interference while other signals are subject to destructive interference. Beamforming techniques can be used at both the transmitting and receiving ends to achieve spatial selectivity. This improvement is referred to as the directivity of the array compared to omnidirectional reception and / or transmission.

[0028] An acoustic sub-bottom profiler (SBP) system is used to determine the physical properties of the seabed and image and characterize the geological information several meters below the seabed. A sub-bottom profiler typically consists of a single-channel sound source that sends acoustic pulses into the shallow seabed sediments. Depending on the difference in acoustic impedance (hardness) of the seabed and the subsequently buried sediment layers, the acoustic pulses bounce back from the seabed and the subsequently buried sediment layers. Acoustic impedance is related to the density of the material and the speed of sound in that material. The different times required for the signal to return and be recorded by the sub-bottom profiler indicate the depth of each layer below the seabed. The surfaces of the different rock layers below the seabed are mapped on a map of the study area.

[0029] The abbreviation of Acoustic Doppler Current Profiler or Acoustic Doppler Profiler is usually ADCP. This system is used to measure the speed at which water moves throughout the water column. ADCP measures water flow using sound, applying the principle of sound waves known as the Doppler effect. The ADCP works by transmitting "pings" of sound into the water at a constant frequency. As the sound waves propagate, they bounce off particles suspended in the flowing water and then reflect back to the instrument. Due to the Doppler effect, the sound waves bouncing off particles moving away from the profiler have a slightly lower frequency when they return. Particles moving towards the instrument send back waves with a higher frequency. The difference in frequency between the waves emitted by the profiler and those it receives is called the Doppler shift. The instrument uses this shift to calculate the speed of the particles and the water around them.

[0030] Sound waves that hit particles farther from the profiler take longer to return than when they hit particles closer. By measuring the time of flight and the Doppler shift when the waves bounce back, the profiler can measure flow speed at many different depths with each series of echoes.

[0031] Swath-sounding sonar systems measure depth on a line extending outward from a sonar transducer. As the survey vessel moves along a track line, the swath-sounding sonar transducer emits sonar signals at right angles to the track line and scans the seabed on each side of the vessel. It sweeps out a depth measurement area, called a swath. The term interferometry refers to a technique used to measure water depth. Interferometry techniques use the phase content of the sonar signal to measure the wavefront returning from the seafloor or other targets (such as seawalls).

[0032] Side scan uses a sonar device that transmits a cone or fan-shaped pulse downward toward the seafloor at a large angle perpendicular to the sensor's path through the water. The sonar device can be towed from a surface vessel or submarine or can be mounted on the hull of a ship. The intensity of the sound waves reflected from the seafloor by this fan-shaped beam is recorded in a series of cross-track slices. When these slices are stitched together along the direction of motion, they form an image of the seafloor within the line of sight (coverage width) of the beam. The sound frequencies used in side scan sonar are typically in the range of 100kHz to 500kHz; the higher the frequency, the better the resolution, but the smaller the range.

[0033] Lidar is a method of determining range (variable distance) by pointing a laser at an object or surface and measuring the time it takes for the reflected light to return to a receiver. It can also be used to make a digital three-dimensional representation of areas on the Earth's surface and on the seafloor in intertidal and near-shore zones by varying the wavelength of light. It has ground, airborne and mobile applications. Lidar is an abbreviation for "light detection and ranging" or "laser imaging, detection and ranging." It is sometimes also called 3D laser scanning, which is a special combination of 3D scanning and laser scanning.

[0034] Lidar uses ultraviolet, visible, or near-infrared light to image objects. It can target a wide range of materials, including non-metallic objects, rocks, rain, chemical compounds, aerosols, clouds, and even individual molecules. Narrow laser beams can map physical features at very high resolution; for example, an aircraft can map terrain at a resolution of 30 centimeters (12 inches) or more.

[0035] When using a sonar transducer, the transmitter is advantageously arranged in a direction parallel to the direction of movement of the lifting hydrofoil. The receiver is advantageously positioned transversely, extending in a direction between the two distal ends of the hydrofoil, substantially orthogonal to the direction of movement of the lifting hydrofoil. Substantially orthogonal to the direction of movement is understood to mean between about 80 and 100 degrees relative to the direction of movement of the lifting hydrofoil. In an advantageous embodiment, the receiver extends completely orthogonally to the direction of movement of the lifting hydrofoil, i.e. defines an angle of 90 degrees with the direction of movement.

[0036] In an embodiment, the at least one survey sensor comprises at least one sonar system which is positioned on the bottom surface in the hydrofoil towards the tail of the wing with respect to the direction of travel, ie at the rear region of the hydrofoil.

[0037] In an embodiment in which the vessel includes two or more lifting hydrofoils, the sonar system is advantageously positioned toward the rear area of ​​the vessel. In one embodiment, the vessel is a crewless vessel, that is, arranged to be remotely controlled and operated without the need for personnel on board to control and operate the vessel. Crewless vessels are also referred to as crewless surface vessels or autonomous surface vessels. This embodiment is advantageous because it reduces the need for humans to interact with physical vessels at sea. On the contrary, operations can be remotely controlled, thereby reducing the risk of injury to personnel. In addition, since personnel are no longer required on board, the size of the vessel can also be reduced. Since the vessel no longer requires space for personnel, such as work, sleep, dining and leisure space, the vessel may be smaller and lighter. This helps to improve energy efficiency and helps to create more sustainable and environmentally friendly ships. In an alternative embodiment, the ship is equipped with a crew. This includes ships equipped with a full crew or ships equipped with a partial crew. Ships equipped with a partial crew can be understood to include ships in which some operations are performed remotely and some operations are actually completed on the ship. Such a ship may only require one or several crew members (such as surveyors) to perform tasks on board that require personal presence. The remaining operations are performed remotely to minimize the presence of personnel on the vessel. By at least partially remotely controlling and operating the vessel, the impact of personnel on safety and vessel size can be reduced. In one embodiment, the vessel includes a launch and recovery system (LARS) for a remotely operated vessel / vehicle (ROV). The ROV can be deployed from the vessel for further investigation and / or operation at locations such as infrastructure. The ROV LARS can be provided so that further exploration, inspection and / or maintenance processes or similar operations can be performed in a single operation. That is, the vessel can directly respond to things identified using one or more survey sensors in the lifting hydrofoils of the vessel. For example, if one or more survey sensors identify a fault in a pipeline, the ROV can be deployed using LARS to further investigate and / or troubleshoot in a single vessel operation.

[0038] By positioning the sonar system towards the tail of the wing, disturbances caused by fluid dynamics are reduced. The sensor operates best when there is a laminar flow of fluid over the surface of the transducer. The disturbance of this flow directly affects the performance of the sensor and its ability to collect high quality accurate data. The shape of the hydrofoil and the placement of the sensor are optimized to minimize the disturbance or interference caused by objects passing through the water.

[0039] In one embodiment, the lifting hydrofoil comprises a high strength material, advantageously at least one of the following materials: glass reinforced plastic (GRP), also known as glass fiber; high density polyethylene (HDPE); polyamide, such as homopolymers and copolymers of PA46, PA48, PA410, PA46 / 6T, PA4T, PA6, PA610, PA6T, PA6 / 6T, PA6 / 10T, PA910, PA9T; polyester; nylon; carbon fiber; plastic; polymer, advantageously an ultra-high molecular weight polymer (such as ultra-high molecular weight polyethylene), an ultra-high density polymer (such as ultra-high density polyethylene); polyoxymethylene; resin; polyamide; polyetheretherketone; or polycarbonate. In the context of the present invention, the term "polymer" is understood to mean a homopolymer or a copolymer. In one embodiment, the lifting hydrofoil comprises at least about 50%, advantageously at least about 70%, more advantageously at least about 90% of non-magnetic material, the non-magnetic material advantageously being a non-conductive material, more advantageously being a non-metallic material. In an embodiment, the lifting hydrofoil comprises aluminum, titanium and / or steel.

[0040] In a preferred embodiment the lifting hydrofoil comprises a composite material, advantageously GRP. The use of composite materials is advantageous because of their high strength, low corrosion and the flexibility with which they can be manufactured in their shape and size.

[0041] In one embodiment, the lifting hydrofoil extends in a transverse direction between the first distal end and the second distal end. The lifting hydrofoil may include a leading end and a trailing end extending in a direction of motion substantially orthogonal to the transverse direction between the first distal end and the second distal end. A center point may be defined between the first distal end and the second distal end. In one embodiment, the connecting structure is connected to the lifting hydrofoil at the center point.

[0042] Attaching the connection structure to the lifting hydrofoil at a central point provides a stable lifting point, thereby limiting the relationship between the moments about the connection structure and the lift generated by the lifting hydrofoil. For example, embodiments in which the connection structure is connected to a single distal end of the lifting hydrofoil, while suitable in some circumstances, can produce bending moments on the connection structure requiring the connection structure to have greater structural integrity.

[0043] In one embodiment, the lifting hydrofoil comprises an elongated portion extending in the direction of motion, the elongated portion extending between the front tip and the rear end, with the center point located between the front tip and the rear end. In one embodiment, the elongated portion of the lifting hydrofoil comprises a propulsion device. In a preferred embodiment, the propulsion device comprises a motor and a propeller, and the motor and the propeller are connected by a longitudinal shaft.

[0044] In a preferred embodiment, the transmitter of the multibeam echosounder transmitter is arranged in the elongated portion, the transmitter extending in the direction of motion of the hydrofoil. In a preferred embodiment, the longitudinal axis, the motor and the propeller are all arranged at the center point of the lifting hydrofoil, located in the elongated portion. The arrangement of arranging the propulsion device at the center point of the lifting hydrofoil and attaching the connecting structure at the center point of the lifting hydrofoil also allows the multibeam echosounder transducer to be arranged in an optimal Millscross arrangement. In this arrangement, the receiver is arranged between the first and second distal ends of the hydrofoil, extending in a direction substantially orthogonal to the direction of motion, and the transmitter is arranged in the elongated portion so that the transmitter extends in a direction substantially parallel to the direction of motion.

[0045] In one embodiment, the lifting hydrofoil comprises a bottom surface, wherein the bottom surface comprises an acoustically transparent window. In one embodiment, the lifting hydrofoil comprises an acoustic sensor, such as a multi-beam echo sounder transducer. Other acoustic sensors may also be provided in the lifting hydrofoil. Advantageously, the acoustic sensor is positioned near the acoustically transparent window, advantageously above the acoustically transparent window. In a preferred embodiment, the acoustic signal transmitted or received through the acoustically transparent window is propagated while minimizing transmission losses. Thus, the acoustic signal received by the acoustic sensor provides high quality data while minimizing the impact on the fluid dynamic characteristics of the lifting hydrofoil.

[0046] The provision of an acoustically transparent window allows positioning of the sensor in the lifting hydrofoil, thereby minimizing the impact on the sensor while maintaining good signal quality. In addition, positioning the sensor behind the acoustically transparent window also maintains the fluid dynamic requirements of the lifting hydrofoil. Therefore, the lifting characteristics of the lifting hydrofoil are limited while maintaining optimal signal quality. In one embodiment, the acoustically transparent window has a high sound transmittance and very little absorption and diffraction of sound, thereby minimizing signal losses due to transmission. In general, transmission loss refers to the cumulative decrease in the intensity of the waveform energy as the wave propagates outward from the sound source, or as the wave propagates through a certain area or through a certain type of structure. The measurement of transmission loss can be expressed in decibels. In one embodiment, the acoustically transparent window is formed of a polymer material, advantageously polyoxymethylene (POM).

[0047] In one embodiment, the lifting hydrofoil includes a rigid internal skeleton structure. The provision of the rigid internal skeleton structure provides a hard mounting structure to fix at least one survey sensor. This allows the outer profile of the wing to be shaped as required to achieve the best stopping effect. The use of a rigid internal skeleton structure, while allowing the outer surface of the hydrofoil to be flexible, also advantageously allows the sensor to be placed in a predetermined position without restricting the hydrodynamic characteristics of the lifting hydrofoil.

[0048] In an embodiment, the rigid internal skeleton structure comprises a material having an elastic modulus of at least about 30 GPa, advantageously at least about 50 GPa, more advantageously at least about 70 GPa, and even more advantageously at least about 90 GPa. In an advantageous embodiment, the rigid internal skeleton structure comprises a high strength material, advantageously at least one of the following materials: glass reinforced plastic (GRP), also known as fiberglass; high density polyethylene (HDPE); polyamides, such as homopolymers and copolymers of PA46, PA48, PA410, PA46 / 6T, PA4T, PA6, PA610, PA6T, PA6 / 6T, PA6 / 10T, PA910, PA9T; polyester; nylon; carbon fiber; plastic; polymer, advantageously an ultra-high molecular weight polymer (such as ultra-high molecular weight polyethylene), an ultra-high density polymer (such as ultra-high density polyethylene); polyoxymethylene; resin; polyamide; polyetheretherketone; or polycarbonate. In the context of the present invention, the term "polymer" is understood to mean a homopolymer or a copolymer. In one embodiment, the rigid internal skeleton structure comprises at least about 50%, advantageously at least about 70%, more advantageously at least about 90% of non-magnetic material, which is advantageously a non-conductive material, more advantageously a non-metallic material. In one embodiment, the lifting hydrofoil comprises aluminum, titanium and / or steel.

[0049] In an embodiment, the connection structure is arranged to adjust the distance between the lifting hydrofoil and the hull of the vessel. In a preferred embodiment, the connection structure is a telescopic structure, which is arranged to be extended and shortened to increase or decrease the distance between the hydrofoil and the hull.

[0050] By allowing the distance between the hull and the lifting hydrofoil to be adjusted in this way, the depth of one or more survey sensors can be controlled. This allows the vessel to be operated at low speeds in shallow water, so that the lift generated by the lifting hydrofoil is insufficient to lift the vessel out of the water. In this case, the depth of the lifting hydrofoil can be reduced to prevent the hydrofoil from colliding with the seabed. Similarly, if the vessel is operating at high speeds in deep water, such that the vessel is completely out of the water, the distance between the hull and the hydrofoil can be increased to provide sufficient depth to stably acquire data.

[0051] In an embodiment, the lifting hydrofoils are arranged to provide lift such that the wetted surface of the vessel's hull is reduced by at least about 20%, advantageously by at least about 40%, more advantageously by at least about 60%, and even more advantageously by at least about 80%.

[0052] Such a lifting force allows a reduction in the wetted surface, thereby reducing the hydrodynamic drag of the water on the vessel, thereby increasing the efficiency and speed of the vessel. Since the lifting hydrofoil includes at least one survey sensor, lifting the vessel does not cause the sensor to be lifted out of the water, nor does it cause the sensor to be lifted in the waves. Therefore, the force increases efficiency and speed, but does not affect the ability of the vessel to obtain the required survey data.

[0053] In a preferred embodiment the lifting hydrofoils are arranged to provide lifting force such that the wetted surface of the hull of the vessel is reduced by 100% thereby lifting the hull as a whole out of the water leaving only the lifting hydrofoils and a portion of the connecting structure in the water.

[0054] In one embodiment, the length of the vessel is between about 1m and 200m, advantageously between about 5m and 100m, more advantageously between about 10m and 80m, and even more advantageously between about 20m and 60m. In one embodiment, the maximum width of the vessel is between about 0.5m and 50m, advantageously between about 1m and 40m, more advantageously between about 5m and 30m, and even more advantageously between 10m and 25m. In a preferred embodiment, the weight of the vessel is between about 100kg and 500 tons, advantageously between 1 ton and 200 tons, more advantageously between 10 tons and 100 tons, and even more advantageously between 20 tons and 60 tons.

[0055] In a preferred embodiment, the width of the lifting hydrofoil from the first distal end to the second distal end is between about 0.5m and 50m, advantageously between about 1m and 40m, more advantageously between about 5m and 30m, and even more advantageously between 10m and 25m. In a preferred embodiment, the vessel comprises a plurality of lifting hydrofoils, the width of the plurality of lifting hydrofoils from the first distal end to the second distal end is between about 0.5m and 50m, advantageously between about 1m and 40m, more advantageously between about 5m and 30m, and even more advantageously between 10m and 25m.

[0056] According to one aspect of the invention there is provided a lifting hydrofoil for use with a vessel for seabed surveying, the lifting hydrofoil being arranged to be connected to a connection structure for connecting the lifting hydrofoil to a hull of the vessel, wherein the lifting hydrofoil comprises at least one survey sensor.

[0057] The embodiments discussed with respect to the vessel according to the invention are equally applicable to lifting hydrofoils.

[0058] In one embodiment, at least one survey sensor includes at least one sensor from the following group of sensors: a sonar system, such as an echo sounder; a single beam, beamforming multi-beam, seafloor profiling system; an acoustic Doppler system; an interferometric sonar system, which includes side scan sonar and line beam bathymetry systems; a laser ranging system, which includes lidar and laser stripping and accompanying camera vision technology.

[0059] According to one aspect of the present invention, a method for acquiring seabed survey data is provided, the method comprising the following steps: providing a vessel according to any one of the embodiments disclosed herein; submerging the hydrofoil of the vessel in water; moving the vessel so that the hydrofoil defines a speed relative to the seabed; and acquiring survey data from the at least one survey sensor.

[0060] According to one aspect of the present invention, a method for producing a vessel according to any one of the embodiments disclosed herein is provided, the method comprising the following steps: providing a hull of the vessel; providing a lifting hydrofoil according to any one of the embodiments disclosed herein; providing a connecting structure for connecting the lifting hydrofoil to the hull, the connecting structure being arranged to convert the lifting force from the lifting hydrofoil to the hull of the vessel; and attaching the connecting structure to the lifting hydrofoil and the hull of the vessel.

[0061] According to one aspect of the present invention, there is provided a use of a vessel according to any one of the embodiments disclosed herein for acquiring seabed survey data. BRIEF DESCRIPTION OF THE DRAWINGS

[0062] In order to describe the manner in which the above and other advantages and features of the present disclosure can be obtained, the principles briefly described above will be described in more detail with reference to the specific embodiments shown in the accompanying drawings. It should be understood that these drawings only illustrate exemplary embodiments of the present disclosure and are therefore not to be considered as limiting the scope thereof. The principles herein will be described and explained in more detail and detail through the use of the accompanying drawings, in which:

[0063] Figure 1 is a three-dimensional view of an embodiment of the present invention showing a lifting hydrofoil;

[0064] Figure 2 is a three-dimensional view of an embodiment of the present invention, showing a vessel for seabed survey;

[0065] Figure 3 is a three-dimensional view of an embodiment of the present invention showing a vessel for seabed survey; and

[0066] Figure 4 is a schematic diagram showing a method for acquiring seabed survey data according to an embodiment of the present invention. DETAILED DESCRIPTION

[0067] The following is a description of certain embodiments of the invention, given by way of example only and with reference to the accompanying drawings.

[0068] Various embodiments of the present invention will be discussed in detail below. Although specific embodiments are discussed, it should be understood that this is for illustrative purposes only. Those skilled in the relevant art will recognize that other components and configurations may also be used without departing from the spirit and scope of the present disclosure. Therefore, the following description and drawings are only illustrative and should not be considered restrictive. Many specific details are described herein to provide a comprehensive understanding of the present disclosure. However, in some cases, in order to avoid ambiguous descriptions, known or conventional details are not described. The embodiments mentioned in the present disclosure may refer to the same embodiment or any other embodiment. Therefore, such references relate to at least one embodiment herein.

[0069] Reference to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic associated with the embodiment is included in at least one embodiment of the present disclosure. The phrase "in one embodiment" appearing in different places in the specification does not necessarily refer to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. In addition, various features described may be shown in some embodiments and not in other embodiments.

[0070] The terms used in this specification generally have their ordinary meanings in the art, in the context of the present disclosure, and in the specific context in which each term is used. Any one or more of the terms discussed herein may use alternative language and synonyms, and there should be no special significance for whether a certain term is elaborated or discussed herein. In some cases, synonyms for certain terms are provided. Narrating one or more synonyms does not exclude the use of other synonyms. The examples used anywhere in this specification (including examples of any terms discussed herein) are only for illustration, and are not intended to further limit the scope and meaning of the present disclosure or any example terms. Similarly, the present disclosure is not limited to the various embodiments given in this specification.

[0071] Without intending to limit the scope of the present disclosure, examples of instruments, devices, methods and related results thereof according to embodiments of the present disclosure are given below. Note that, for the convenience of the reader, titles or subtitles may be used in the examples, but this should never limit the scope of the present disclosure. Unless otherwise defined, the technical and scientific terms used herein have the meanings commonly understood by those of ordinary skill in the art related to the present disclosure. In the event of a conflict, this document (including definitions) shall prevail.

[0072] Other features and advantages of the present disclosure will be set forth in the following description, some of which will be apparent from the description or may be learned by practicing the principles disclosed herein. The features and advantages of the present disclosure may be realized and obtained by the instruments and combinations specifically indicated in the appended claims. These and other features of the present disclosure will become more apparent from the following description and the appended claims or may be learned by practicing the principles described herein.

[0073] Reference Figure 1 , showing a three-dimensional view of a lifting hydrofoil 10. The lifting hydrofoil 10 in the illustrated embodiment is arranged for use with a vessel for seabed surveying. The lifting hydrofoil 10 is arranged to be connected to a connection structure 3, which provides a connection between the lifting hydrofoil 10 and the hull 2 ​​of the vessel 1. In the illustrated embodiment, the connection structure 3 forms an integral connection with the lifting hydrofoil 10. The lifting hydrofoil comprises at least one survey sensor 4. The at least one survey sensor may be any suitable survey sensor 4.

[0074] In one embodiment, the at least one survey sensor 4 includes at least one sensor from the following group of sensors: a sonar system, such as an echo sounder; a single beam, beamforming multi-beam, seabed profile measurement system; an acoustic Doppler system; an interferometric sonar system, which includes a side scan sonar and a line beam bathymetric system; a laser ranging system, which includes a lidar and laser stripping and accompanying camera vision technology.

[0075] In the illustrated embodiment, the lifting hydrofoil extends in a transverse direction between a first distal end 11 and a second distal end 12, and wherein the lifting hydrofoil 10 comprises a leading end 13 and a trailing end 14 extending in a direction of motion substantially orthogonal to the transverse direction, wherein a center point 15 is defined between the first distal end 11 and the second distal end 12. In the illustrated embodiment, the connection structure 3 is connected to the lifting hydrofoil 10 at the center point 15. Thus, the lifting force generated by the lifting hydrofoil 10 is converted into a lifting force on the hull 2 ​​of the vessel 1, such that the lifting force from the lifting hydrofoil 10 provides a balanced upward force.

[0076] In the embodiment shown, the lifting hydrofoil 10 comprises an elongated portion 16. The elongated portion 16 extends in the direction of movement of the vessel 1 and the lifting hydrofoil 10. The elongated portion 16 extends between a front tip 17 and a rear end 18. The center point 15 is located between the front tip 17 and the rear end 18.

[0077] In the embodiment shown, the elongated portion 16 of the lifting hydrofoil 10 comprises a propulsion device 20. The propulsion device 20 comprises a motor 21 and a propeller 22, the motor 21 being advantageously located in the elongated portion 16. The motor 21 and the propeller 22 are advantageously connected by a longitudinal shaft between the motor 21 and the propeller 22.

[0078] Now refer to Figure 2 , a vessel 1 for seabed survey is shown. The vessel 1 comprises a hull 2, a lifting hydrofoil 10 and a connecting structure 3 for connecting the lifting hydrofoil 10 to the hull 2 ​​of the vessel 1. In the embodiment shown, the vessel 1 comprises two lifting hydrofoils 10, which are spaced apart at a distance in the moving direction of the vessel 1. Each of the two lifting hydrofoils 10 is connected to the hull 2 ​​of the vessel 1 by two connecting structures 3. The connecting structure 3 is connected to the lifting hydrofoil 10 at two laterally spaced positions. Similarly, the connecting structure 3 is connected to the hull 2 ​​of the vessel 1 at two laterally spaced positions on the vessel. Thus, a stable position of the vessel 1 is achieved.

[0079] The lifting hydrofoil 10 of the illustrated embodiment includes at least one survey sensor 4 according to any embodiment disclosed herein. In one embodiment, the lifting hydrofoil 10 includes a bottom surface 19, and the bottom surface includes an acoustic transparent window 30. In one embodiment, the lifting hydrofoil 10 includes an acoustic sensor 4, such as a multi-beam echo sounder transducer. Other acoustic sensors may also be provided in the lifting hydrofoil 10. The acoustic sensor 4 is located near the acoustic transparent window 30, advantageously located above the acoustic transparent window 30. The transmission loss of the acoustic signal transmitted or received through the acoustic transparent window 30 is minimized during the propagation process. Therefore, the acoustic signal received by the acoustic sensor 4 provides high-quality data while minimizing the impact on the fluid dynamic characteristics of the lifting hydrofoil 10.

[0080] The provision of the acoustically transparent window 30 allows the sensor to be positioned in the lifting hydrofoil 10, thereby minimizing the impact on the sensor 4 while maintaining good signal quality. In addition, positioning the sensor 4 behind the acoustically transparent window 30 maintains the fluid dynamic requirements of the lifting hydrofoil 10. Therefore, the lifting characteristics of the lifting hydrofoil 10 are limited while maintaining optimal signal quality.

[0081] Now refer to Figure 3, shows another embodiment of a vessel 1 for seabed survey. In the embodiment shown, the vessel 1 comprises a hull 2 ​​and two curved lifting hydrofoils 10. The lifting hydrofoils 10 are connected to the hull 2 ​​via a plurality of connecting structures 3. In the embodiment shown, the connecting structures 3 each comprise two struts 31 extending from the hydrofoils 10 to the hull 2 ​​of the vessel 1. This further increases the structural integrity of the connecting structure 3 between the lifting hydrofoils 10 and the hull 2, and increases the lateral movement resistance of the vessel 1 relative to the water.

[0082] Now refer to Figure 4 , a schematic diagram outlining a method of acquiring seabed survey data is shown to outline the following steps: providing 401 a vessel according to any of the embodiments disclosed herein; submerging 402 a hydrofoil of the vessel in water; moving 403 the vessel so that the hydrofoil defines a velocity relative to the seabed; and acquiring 404 survey data from at least one survey sensor.

[0083] The invention has been described with reference to certain embodiments discussed above. It will be appreciated that these embodiments are susceptible to various modifications and alternative forms well known to those skilled in the art.

[0084] In addition to the above modifications, further modifications may be made to the structures and techniques described herein without departing from the spirit and scope of the invention.Therefore, although specific embodiments have been described, these are merely examples and do not limit the scope of the invention.

Claims

1. A vessel (1) for seabed survey, the vessel (1) include: hull(2); at least one lifting hydrofoil (10); as well as a connecting structure (3) for connecting the at least one lifting hydrofoil (10) to the hull (2), the connecting structure (3) being arranged to transfer a lifting force from the at least one lifting hydrofoil (10) to the hull (2) of the vessel (1), Therein, the at least one lifting hydrofoil (10) comprises at least one surveying sensor (4).

2. The vessel (1) according to claim 1, in, The at least one survey sensor (4) comprises at least one sonar system.

3. A vessel (1) according to any one of the preceding claims, in, The vessel is an uncrewed vessel.

4. Vessel (1) according to any of the preceding claims, further comprising a launch and recovery system for a Remotely Operated Vessel / Vehicle (ROV).

5. A vessel (1) according to any one of the preceding claims, in, The at least one surveying sensor (4) comprises at least one sonar system which is positioned in the at least one lifting hydrofoil (10) at a rear region of the at least one lifting hydrofoil (10) relative to an expected direction of movement of the at least one lifting hydrofoil (10).

6. A vessel (1) according to any one of the preceding claims, in, The at least one lifting hydrofoil (10) extends in a transverse direction between a first distal end (11) and a second distal end (12), and wherein the at least one lifting hydrofoil (10) comprises a front end (13) and a rear end (14), wherein the front end (13) and the rear end (14) extend in a direction of movement substantially orthogonal to the transverse direction, wherein a center point (15) is defined between the first distal end (11) and the second distal end (12), and wherein the connecting structure (3) is connected to the at least one lifting hydrofoil (10) at the center point (15).

7. A vessel (1) according to any one of the preceding claims, in, The at least one lifting hydrofoil (10) comprises a bottom surface (19), wherein the bottom surface (19) comprises an acoustically transparent window (30), and wherein the at least one lifting hydrofoil (10) comprises an acoustic sensor (4).

8. A vessel (1) according to any one of the preceding claims, in, The at least one lifting hydrofoil (10) comprises a rigid internal skeleton structure.

9. A vessel (1) according to any one of the preceding claims, in, The connection structure (3) is arranged to adjust the distance between the at least one lifting hydrofoil (10) and the hull (2) of the vessel (1).

10. A lifting hydrofoil (10) for use with a vessel (1) for seabed surveying, the lifting hydrofoil (10) being arranged to be connected to a connection structure (3) for connecting the lifting hydrofoil (10) to a hull (2) of the vessel (1), in, The lifting hydrofoil (10) comprises at least one survey sensor (4).

11. The lifting hydrofoil (10) according to claim 10, in, The at least one survey sensor (4) comprises at least one sonar system.

12. A connection structure (3) for connecting a lifting hydrofoil (10) to a hull (2) of a vessel (1) according to any one of claims 1 to 9, the connection structure (3) being arranged to transfer a lifting force from the lifting hydrofoil (10) to the hull (2) of the vessel (1), and in, The connection structure includes a data transmission and / or power transmission channel.

13. A method for obtaining seabed survey data, the method The following steps are involved: - providing a vessel (1) according to any one of claims 1 to 9; - immersing at least one lifting hydrofoil (10) of the vessel (1) in water; - moving the vessel (1) such that the at least one lifting hydrofoil (10) defines a speed relative to the seabed; and - Acquiring survey data from at least one survey sensor (4).

14. A method for producing a vessel (1) according to any one of claims 1 to 9, the method The following steps are involved: - providing a hull (2) of a vessel (1); - providing at least one lifting hydrofoil (10) according to any one of claims 10 to 11; - providing a connection structure (3) for connecting at least one lifting hydrofoil (10) to the hull (2), the connection structure (3) being arranged to transfer a lifting force from the at least one lifting hydrofoil (10) to the hull (2) of the vessel (1); as well as - Attaching the connection structure (3) to the at least one lifting hydrofoil (10) and to the hull (2) of the vessel (1).

15. Use of a vessel (1) according to any one of claims 1 to 9 for acquiring seabed survey data.

Images