Hydrolift system for watercraft flotation and propulsion

Abstract

A hydrolift system includes a rotor, a drive shaft, and a hydrolift control system. The rotor operates in water, and in response to being rotated, generates hydrodynamic lift. The drive shaft is mechanically coupled to the rotor and transmits rotational power to the rotor. The hydrolift control system operatively coupled to the drive shaft and the rotor, controls operation of the rotor and the drive shaft. The rotation of the rotor in water generates hydrodynamic lift which is independent of forward translational motion or movement of the watercraft. The hydrolift control system regulates lift output of the hydrolift system such that the watercraft is selectively operable in a buoyancy-supported flotation state and a lift-based flotation state in which the hydrodynamic lift generated by the rotor supports at least a portion of a weight of the watercraft.

Description

Attorney Docket No.: 2032-0011-PCTHYDROLIFT SYSTEM FOR WATERCRAFT FLOTATION AND PROPULSION CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of the filing date of U.S. Provisional Application No. 63 / 740,319, filed on December 31, 2024, and entitled Lift-Based Mechanism for Watercraft Flotation and Propulsion, the content of which is incorporated herein by reference in its entirety.TECHNICAL FIELD

[0002] The present disclosure relates to a hydrolift system for watercraft flotation and propulsion, and specifically to a system using rotating hydrofoils in water that creates a lift force to enable flotation and propulsion for watercrafts.BACKGROUND

[0003] The development of efficient and versatile watercraft designs has been a longstanding focus in marine engineering. Traditional hull-based watercraft rely on buoyancy and drag reduction to achieve flotation and propulsion. While effective, these designs are often limited by high resistance at increased speeds and diminished maneuverability. Hydrofoils, which use lift generated by submerged wing-like structures to elevate the hull above the water, have emerged as a solution to minimize drag and improve performance. However, existing hydrofoil systems are frequently constrained by their fixed geometries, complex mechanical systems, and reduced efficiency in varying water and operational conditions.

[0004] Modem applications demand watercraft capable of high efficiency, adaptability, and reduced environmental impact across diverse operational scenarios. From recreational boating to cargo transport, achieving optimal performance under varying speeds and loads remains a challenge for existing hydrofoil designs. A need exists for innovative flotation and propulsion mechanisms that provide improved hydrodynamic efficiency, stability, and adaptability, enabling watercraft to operate effectively in a wide range of conditions while addressing modern sustainability concerns.

[0005] Conventional hydrofoil systems employ fixed or passively controlled hydrofoil surfaces that rely on forward translational motion of the watercraft to generate lift. As a result, such systems provide little or no lift at zero or low forward speeds and typically operate efficiently only within a narrow speed range. Outside this range, fixed hydrofoils mayAttorney Docket No.: 2032-0011-PCTexperience reduced lift, increased lift-induced drag, diminished controllability, and poor performance under varying payload and operating conditions.SUMMARY

[0006] A system to enable watercrafts to float above water using a rotary hydrofoil assembly is described.

[0007] In some aspects, the techniques described herein relate to a hydrolift system for generating hydrodynamic lift for a watercraft. The hydrolift system includes a rotor, a drive shaft, and a hydrolift control system. The rotor operates in water, and in response to being rotated, generates hydrodynamic lift. The drive shaft is mechanically coupled to the rotor and transmits rotational power to the rotor. The hydrolift control system operatively coupled to the drive shaft and the rotor, controls operation of the rotor and the drive shaft. The rotation of the rotor in water generates hydrodynamic lift which is independent of forward translational motion or movement of the watercraft. The hydrolift control system regulates lift output of the hydrolift system such that the watercraft is selectively operable in a buoyancy-supported flotation state and a lift-based flotation state in which the hydrodynamic lift generated by the rotor supports at least a portion of a weight of the watercraft.

[0008] In some aspects, the techniques described herein relate to a method of operating a watercraft including: providing a watercraft having one or more hydrolift systems in water; in response to the one or more hydrolift systems being inactive, supporting the watercraft in the water by buoyancy; activating at least one hydrolift system mounted to the watercraft; rotating a rotor of the at least one hydrolift system in the water to generate hydrodynamic lift that is independent of forward translational motion or movement of the watercraft; controlling operation of the at least one hydrolift system using a hydrolift control system to regulate lift output such that the watercraft transitions from a buoyancy- supported flotation state to a lift-based flotation state in which hydrodynamic lift generated by the rotor supports at least a portion of a weight of the watercraft; and deactivating operation of the at least one hydrolift system to allow the watercraft to return to buoyancy-supported flotation.BRIEF DESCRIPTION OF DRAWINGS

[0009] Fig. 1 illustrates a hydrolift system submerged in water.

[0010] Fig. 2A illustrates a side view of a watercraft with multiple hydrolift systems installed.Attorney Docket No.: 2032-0011-PCT

[0011] Fig. 2B illustrates a front view of a watercraft with multiple hydrolift systems installed.

[0012] Fig. 3 illustrates a small watercraft equipped with one or more hydrolift systems mounted beneath a watercraft.

[0013] Fig. 4 illustrates an implementation in which a hydrolift system is configured to generate both lift and thrust by orienting a rotor of the hydrolift system assembly at an angle relative to a watercraft.

[0014] Fig. 5 illustrates a hydrolift system implementation in which hydrodynamic lift is generated by a rotor disc.

[0015] Fig. 6A illustrates a hydrolift system in a deployed position.

[0016] Fig. 6B illustrates a hydrolift system in a retracted position.

[0017] Fig. 7 illustrates a hydrolift system implementation in which a rotary hydrofoil assembly is enclosed within a protective rotor screen.

[0018] Fig. 8A illustrates a watercraft in a lift-based operating mode in which a hydrolift system is switched on.

[0019] Fig. 8B illustrates a watercraft in a non-lift operating mode in which a hydrolift system is switched off.

[0020] Fig. 9A illustrates a watercraft in a lift-based operating mode in which a hydrolift system is actively driven to generate hydrodynamic lift.

[0021] Fig. 9B illustrates a watercraft in a buoyancy-supported operating mode in which a hydrolift system is switched off or otherwise not generating lift and flotation is provided by flotation collars.

[0022] Fig. 10 illustrates a system-level architecture of a hydrolift system integrated with a watercraft.

[0023] Fig. 11 is a flowchart of a method of operating a watercraft equipped with one or more hydrolift systems to generate hydrodynamic lift and control watercraft motion.

[0024] Fig. 12 is a flowchart of a method of operating a watercraft in which a hydrolift system is activated to rotate a rotor in water to generate hydrodynamic lift and selectively transition the watercraft between buoyancy-supported flotation and lift-based flotation.

[0025] Fig. 13 is a flowchart describing a basic control loop for the hydrolift control system.

[0026] Fig. 14 depicts a rotor orientation in a hydrolift system.Attorney Docket No.: 2032-0011-PCTDETAILED DESCRIPTION

[0027] Conventional watercraft propulsion and flotation technologies suffer from inherent limitations that restrict performance, efficiency, and operational flexibility.Traditional buoyancy-supported hulls rely on displacement of water for flotation, resulting in significant hydrodynamic drag, particularly at higher speeds. Fixed hydrofoil systems reduce hull-water contact and associated drag; however, such systems depend on forward translational motion of the watercraft to generate lift. As a result, fixed hydrofoils provide little or no lift at zero or low forward speeds, exhibit narrow optimal operating ranges, and often suffer from reduced efficiency, high lift-induced drag, and limited controllability under varying pay loads and operating conditions.

[0028] Existing propulsion systems, including propellers, water jets, and cycloidal or azimuth drives, are primarily configured to generate thmst rather than primary lift. These systems do not provide a mechanism for actively generating hydrodynamic lift sufficient to support a watercraft independently of forward translational motion, nor do they enable selective transition between buoyancy-supported and lift-based flotation states. Consequently, conventional systems require separate structures or mechanisms to address flotation, propulsion, and stability, thereby limiting adaptability.

[0029] What is needed is a hydrodynamic lift system capable of generating primary lift independent of forward translational motion of the watercraft, enabling lift-based flotation at zero or low speed while maintaining controllable lift output across a wide range of operating conditions. What is further needed is a system that allows selective transition between buoyancy-supported and lift-based flotation states, supports scalability across different watercraft sizes, and enables coordinated control of lift for stability, maneuverability, and propulsion.

[0030] The hydrolift systems described herein address these needs by employing actively driven rotary hydrofoil assemblies configured to generate hydrodynamic lift through rotation in water, independent of watercraft translational motion. By controlling rotor rotational speed, blade angle of attack, and rotor orientation, the disclosed systems enable precise regulation of lift output, selective replacement or supplementation of buoyancy, and, in certain implementations, simultaneous generation of lift and thrust. This approach provides improved efficiency, enhanced maneuverability, reduced hydrodynamic drag, and expanded operational capability relative to conventional buoyancy-supported hulls, fixed hydrofoil systems, and thrust-only propulsion technologies.Attorney Docket No.: 2032-0011-PCT

[0031] Unlike fixed hydrofoil systems, the hydrolift system described herein generates hydrodynamic lift through active rotation of hydrofoil blades in water. As such, relative motion between the hydrofoils and the surrounding water is produced by rotor rotation rather than by forward motion of the watercraft. As a result, hydrodynamic lift may be generated while the watercraft is stationary or moving at low speed.

[0032] As used herein, a hydrolift system refers to an integrated lift-generating assembly including at least a rotor, a drive shaft mechanically coupled to the rotor, and a hydrolift control system operatively coupled to the drive shaft and the rotor. The hydrolift system is configured to generate hydrodynamic lift when the rotor is rotated in water under control of the hydrolift control system. In certain implementations, the hydrolift system may further optionally include a power transmission assembly and an engine or motor. In certain implementations, the hydrolift system generates primary lift sufficient to support all or a majority of the weight of the watercraft during operation in water.

[0033] Fig. 1 illustrates a hydrolift system submerged in water. As depicted, a watercraft 102 includes at least one hydrolift system that generates lift sufficient to support at least a portion of the weight of the watercraft. The hydrolift system includes a rotor 108 positioned below the watercraft 102, a drive shaft 106 mechanically coupled to the rotor 108, and a hydrolift control system 1014 (described in Fig. 10) configured to control operation of the rotor 108 and the drive shaft 106.

[0034] The drive shaft 106 is operatively coupled to a power source, which in the illustrated implementation includes an engine 101 connected through a power transmission assembly 104. The terminology power transmission assembly, drive coupling, or transmission may be used interchangeably.

[0035] In alternate implementations, the power source may include a motor 1010 powered by batteries 1012 or another energy storage system. The drive shaft 106 transmits rotational power to the rotor 108 under control of the hydrolift control system 1014.

[0036] The rotor 108 includes a rotor head 110 and one or multiple rotor blades 112 extending radially from the rotor head 110. Each rotor blade 112 is shaped as a hydrofoil that may generate hydrodynamic lift when rotated through water 114. The hydrolift control system 1014 controls one or more operating parameters of the hydrolift system, including rotor rotational speed (RPM) and, in some implementations, blade angle of attack, in order to regulate lift generation as well as the rotor orientation of the hydrolift system relative to the watercraft.Attorney Docket No.: 2032-0011-PCT

[0037] In some implementations, the hydrolift control system adjusts rotor rotational speed and blade angle of attack to regulate lift output while accounting for hydrodynamic drag acting on the rotor. The rotor head 110 may also be referred to as a hub. The rotor head 110 may be the center section where each of the rotor blades 112 join together and where additional mechanisms may be included to enable modifying the angle of each of the rotor blades 112 with respect to a given plane. The rotor head 110 may include sensors and other actuators to individually move each of the rotor blades 112.

[0038] In an implementation, the drive shaft 106 is mechanically coupled to the rotor 108, so that the drive shaft 106 can transmit rotary motion to the rotor head 110 and each of the rotor blades 112.

[0039] The magnitude of hydrodynamic lift generated by the hydrolift system may be regulated by controlling one or more operating parameters, including rotor rotational speed, rotor orientation and blade angle of attack. By adjusting these parameters, lift output may be increased or decreased to accommodate changes in payload mass, operating conditions, or desired watercraft behavior. Operating parameters of the hydrolift systems may be adjusted in response to different environmental water conditions.

[0040] During operation, rotation of the rotor 108 in the water 114 generates hydrodynamic forces on each of the rotor blades 112. These forces include a lift force 116 acting generally upward on the watercraft 102 and a drag force 118 acting generally opposite relative motion between the blades and surrounding water. The lift force 116 generated by the hydrolift system is independent of forward translational motion or movement of the watercraft 102 and may be generated while the watercraft is stationary or moving at low speed. Forward translational motion or movement may refer to speed, forward motion, a motion vector, etc.

[0041] In some implementations, the lift force 116 generated by the hydrolift system is configured to reduce contact between the hull of the watercraft and the water 114 during operation. This is referred to as a lift-based flotation state. In other implementations, the lift force 116 supplements buoyancy such that the hydrolift system supports only a portion of the weight of the watercraft 102. This is referred to as a buoyancy-supported state. Therefore, the hydrolift system is configured to selectively transition a watercraft between a buoyancy-supported flotation state and a lift-based flotation state. The transition is achieved by selectively activating, deactivating, or adjusting operation of one or more hydrolift systems to increase or decrease hydrodynamic lift generated by rotation of the rotor. In the lift-based flotation state, hydrodynamic lift generated by rotation of the rotor in water supports at least aAttorney Docket No.: 2032-0011-PCTportion of the weight of the watercraft, while in the buoyancy-supported flotation state the hydrolift system is inactive and buoyant forces support the watercraft. In a complete liftbased flotation state, the watercraft hull is fully lifted out of water so there is no direct contact between the watercraft hull and the water.

[0042] The hydrolift control system 1014 is further configured to modulate lift output in response to operating conditions, payload mass, or operator input by adjusting rotor speed, blade angle of attack, rotor orientation or all. Multiple hydrolift systems may be provided on a single watercraft 102 and controlled individually or collectively to distribute lift and maintain stability. In some implementations, the hydrolift control system 1014 adjusts rotor rotational speed, rotor orientation and blade angle of attack to regulate lift and drag characteristics based on watercraft mass, operating conditions, or translational motion or movement. In some implementations, different hydrolift systems mounted to a single watercraft are operated at different lift outputs or orientations to intentionally generate asymmetric lift or thrust forces, enabling active control of yaw, pitch, roll, or combined watercraft motion.

[0043] In one example implementation, a watercraft having a total mass of approximately 10,000 kg is supported by four rotary hydrofoil assemblies, each having a rotor radius of approximately 1-2 meters. The rotors arc driven at rotational speeds in the range of hundreds of revolutions per minute (RPM) such that the combined lift force generated by the hydrofoils matches the gravitational force on the watercraft. Lift may be increased or decreased by adjusting rotor speed, blade angle of attack, rotor orientation of the hydrolift system, or some combination of these. In this configuration, the watercraft may be fully lifted above the water surface during operation.

[0044] In another example implementation, a large watercraft having a displacement on the order of tens of thousands of metric tons is supported by one or more rotary hydrofoil assemblies distributed along the hull. Each assembly may have a rotor radius on the order of several meters and be driven at rotational speeds sufficient to collectively generate lift matching the watercraft’s weight. Lift distribution across the assemblies is controlled to maintain stability of the watercraft while minimizing drag.

[0045] The hydrofoil blades may be operated at depths and rotational speeds selected to avoid cavitation, and blade geometry and operating parameters may be adjusted accordingly.Attorney Docket No.: 2032-0011-PCT

[0046] In implementations employing multiple rotary hydrofoil assemblies, the system is configured such that failure or shutdown of one assembly does not result in loss of flotation, with remaining assemblies compensating by increasing lift output.

[0047] The rotor blades may employ any hydrofoil geometry suitable for generating hydrodynamic lift in water, including symmetric or cambered profiles, and may be selected based on operating speed, load, and cavitation considerations.

[0048] Adjusting an orientation of a rotational axis of the rotary hydrofoil rotor relative to an upright reference direction, also known as rotor orientation, causes rotation of the rotor in water to produce both lift and thrust components, enabling the hydrolift system to provide flotation and propulsion simultaneously. A second horizontal force, the drag force, is also created, which needs to be minimized.

[0049] By reducing or eliminating contact between the hull and the surrounding water during lift-based operation, the hydrolift system may reduce hydrodynamic drag relative to buoyancy- supported operation. This reduction in drag may improve energy efficiency, increase achievable operating speeds, and enhance maneuverability under certain operating conditions.

[0050] Fig. 2A and Fig. 2B illustrate a large watercraft 200 with multiple hydrolift systems installed. Specifically, the watercraft 200, such as a cargo ship, tanker, bulk carrier, or similar commercial vessel, is equipped with multiple hydrolift systems 204 mounted along a ship hull 206. The watercraft 200 is configured to transport cargo 202 while being at least partially supported above the water by lift generated by the hydrolift systems 204 during operation.

[0051] Fig. 2A illustrates a side view of the watercraft 200, in which multiple hydrolift systems 204 are distributed along the length of the ship hull 206. The hydrolift systems 204 are positioned below the bottom of the ship hull 206 such that their associated rotors operate in water and generate hydrodynamic lift forces acting upward on the watercraft 200. The longitudinal spacing of the hydrolift systems 204 may be selected to distribute lift along the length of the ship hull 206 and to reduce bending moments and structural loads on the ship hull.

[0052] Fig. 2B illustrates a front view of the watercraft 200, illustrating hydrolift systems 204 mounted on opposing sides of the ship hull 206. The hydrolift systems 204 may be arranged symmetrically about a centerline of the watercraft 200 to provide balanced lift and to maintain roll stability during operation. In some implementations, additional hydroliftAttorney Docket No.: 2032-0011-PCTsystems 204 may be mounted near a centerline of the ship hull 206 or at other locations depending on the watercraft size, hull geometry, and desired lift distribution.

[0053] Each hydrolift system 204 includes at least a rotor, a drive shaft, and a hydrolift control system, as described herein. The hydrolift systems 204 may be powered by one or more engines or motors located on the watercraft 200 and may be controlled individually or collectively by the hydrolift control system to regulate lift output. By independently controlling the lift generated by different hydrolift systems 204, the hydrolift systems 204 may actively manage pitch, roll, and heave of the watercraft 200.

[0054] In operation, the hydrolift systems 204 generate lift sufficient to support a substantial portion of the weight of the watercraft 200 (e.g., over 5%) and its cargo 202. In some implementations, the combined lift generated by the hydrolift systems 204 reduces or substantially (e.g., more than 1%) eliminates contact between the ship hull 206 and the surrounding water, thereby reducing hydrodynamic drag associated with hull displacement. In other implementations, the hydrolift systems 204 supplement buoyancy such that the watercraft 200 operates in a partially lifted state.

[0055] The number, size, and placement of hydrolift systems 204 may be selected based on watercraft vessel displacement, cargo mass, operating speed, and environmental conditions. The illustrated arrangement demonstrates scalability of the hydrolift system to large commercial watercraft vessels, enabling lift-based operation for ships that traditionally rely entirely on buoyancy for support.

[0056] In smaller watercraft implementations, including recreational, patrol, or highspeed utility craft, the hydrolift systems enable lift-based operation at relatively low forward speeds and with compact rotor dimensions. For such small watercraft, the ability to generate lift independent of forward translational motion allows rapid transition from displacement or semi-displacement operation to a fully or partially lifted state, significantly reducing hydrodynamic drag and improving acceleration, maneuverability, and energy efficiency. This capability further enables operating regimes and maximum speeds that are impractical or unattainable for conventional buoyancy-supported hulls of comparable size.

[0057] For purposes of this disclosure, the phrase “independent of forward translational motion” refers to hydrodynamic lift that is generated without requiring forward movement of the watercraft through the water. In such implementations, hydrodynamic lift is produced by rotation of the rotor relative to the surrounding water, such that lift may be generated while the watercraft is stationary, moving at low speed, or moving at higher speed.Attorney Docket No.: 2032-0011-PCTForward translational motion of the watercraft may be present during operation but is not needed to generate the hydrodynamic lift.

[0058] Fig. 3 illustrates a small watercraft 300 equipped with one or more hydrolift systems 302 mounted beneath the watercraft. The hydrolift systems 302 are positioned such that their associated rotors extend below the lower surface of the watercraft 300 and operate in water to generate hydrodynamic lift.[00059J In the illustrated implementation, the hydrolift systems 302 are arranged to provide balanced lift about a centerline of the watercraft 300. The number and placement of hydrolift systems 302 may be selected based on watercraft size, payload, and desired operating characteristics. For example, a single hydrolift system 302 may be used for very small watercraft, while two or more hydrolift systems 302 may be used to improve stability and load distribution.

[0060] Each hydrolift system 302 includes a rotor, a drive shaft, and a hydrolift control system, as defined elsewhere herein. During operation, the hydrolift control system regulates rotor speed (RPM), the rotor orientation and, in some implementations, blade angle of attack to generate lift sufficient to support at least a portion of the weight of the watercraft 300. The lift generated by the hydrolift systems 302 is independent of forward translational motion or movement of the watercraft 300.

[0061] In some implementations, the hydrolift systems 302 generate sufficient lift to raise the watercraft 300 such that contact between the hull and the water is substantially reduced or eliminated during operation. This reduces hydrodynamic drag and enables higher acceleration, improved maneuverability, and increased maximum speed compared to conventional buoyancy-supported small watercraft. In other implementations, the hydrolift systems 302 supplement buoyancy such that the watercraft 300 operates in a partially lifted state.

[0062] The implementation depicted in Fig. 3 demonstrates the suitability of the hydrolift system for small and lightweight watercraft, including recreational watercraft, patrol vessels, and high-speed utility watercraft, where rapid transition to lift-based operation and efficient high-speed performance are desirable.

[0063] In some implementations, the hydrodynamic lift is generated by relative motion between the rotating rotor and the surrounding water, rather than by forward motion of the watercraft through the waler.

[0064] In some implementations, the rotor is coupled to a mounting structure that supports the rotor relative to the watercraft and permits adjustment of an orientation of aAttorney Docket No.: 2032-0011-PCTrotational axis of the rotor, the rotor orientation. The mounting structure may include one or more pivots, actuators, linkages, or articulated supports configured to adjust the orientation of the rotor during operation.

[0065] Fig. 4 illustrates an implementation in which a hydrolift system is configured to generate both lift and thrust by orienting a rotor of the hydrolift system assembly at an angle relative to a watercraft 402, the rotor orientation. In this implementation, an engine 400 provides rotational power to a transmission 404, which drives a drive shaft 406 mechanically coupled to a rotor 408. The rotor 408 includes a rotor head 410 and one or more rotor blades 412 shaped as hydrofoils.

[0066] The rotor 408 is oriented such that its rotational axis of rotation is adjustable relative to an upright reference direction of the watercraft. During operation, rotation of the rotor 408 in water 420 generates hydrodynamic forces on the rotor blades 412 that resolve into a resultant hydrodynamic force 418. The resultant hydrodynamic force 418 generated by rotation of the rotor 408 may be decomposed into a lift force 414 acting generally upward on the watercraft 402, a thrust force 419 acting generally along a direction of motion of the watercraft, and a drag force 416 opposing rotation of the rotor. The hydrodynamic forces include a lift component acting generally upward on the watercraft 402 and a thrust component acting generally along a direction of motion of the watercraft. The relative motion between the rotating rotor 408 and the surrounding water produces hydrodynamic lift regardless of whether the watercraft 402 is undergoing forward translational motion.

[0067] By adjusting the rotor orientation of the rotor 408, the relative magnitudes and directions of the lift force 414 and thrust force 419 may be controlled. In this manner, the hydrolift system may simultaneously provide vertical lift and forward propulsion. The tilt angle may be adjusted dynamically during operation to optimize lift, thrust, or maneuverability based on operating conditions.

[0068] Control of the hydrolift system is performed by a hydrolift control system that regulates rotor rotational speed, blade angle of attack in implementations employing variablepitch blades, and rotor orientation. This coordinated control enables precise management of the resultant hydrodynamic force 418 to maintain stability, control acceleration, and execute directional maneuvers.

[0069] In some implementations, multiple tilted hydrolift systems may be employed on a single watercraft 402 to provide differential thrust and lift, enabling yaw, pitch, and roll control without the need for conventional rudders or propellers. The implementation shown in Fig. 4 demonstrates integration of lift generation and propulsion within a single hydroliftAttorney Docket No.: 2032-0011-PCTsystem, reducing mechanical complexity and improving efficiency relative to separate lift and propulsion systems.

[0070] In order to create forward thrust, a separate propeller or water jets or other known mechanisms may be utilized. Similar to traditional watercrafts, separate propellers may be used to provide thrust independently of the hydrolift system. Alternatively, a waterjet may be expelled through an impeller to create thrust, independent of the hydrolift system.[00071 J Fig. 5 illustrates a hydrolift system implementation in which hydrodynamic lift is generated by a rotor disc 502 rather than by discrete hydrofoil blades. In this implementation, a drive shaft 500 is mechanically coupled to the rotor disc 502 and configured to rotate the rotor disc about a central rotational axis under control of the hydrolift control system. In this embodiment, the hydrolift system consists of the rotor disc 502, the drive shaft 500 and the hydrolift control system.

[0072] The rotor disc 502 is positioned such that at least a portion of the disc is in contact with water 504 during operation. Rotation of the rotor disc 502 relative to the water 504 generates hydrodynamic pressure on the disc surface, producing lift acting on the associated watercraft. The lift generated by the rotor disc 502 results from actively driven relative motion between the disc and the water and is therefore independent of forward translational motion or movement of the watercraft.

[0073] In certain implementations, the rotor disc 502 is operated in a partially submerged or surface- skimming configuration such that hydrodynamic lift supports a substantial portion of the weight of the watercraft. In such configurations, the rotor disc 502 may produce a hydroplaning effect in which contact between the hull and the water is reduced or eliminated during operation. The magnitude of lift generated by the rotor disc 502 may be controlled by adjusting rotational speed of the disc as well as the rotor orientation.

[0074] The drive shaft 500 may be coupled to an engine, motor, or transmission system as described elsewhere herein, and rotational speed and rotor orientation of the rotor disc 502 may be regulated by the hydrolift control system to control lift output in response to payload, operating conditions, or operator input.

[0075] The disc-based hydro lift system illustrated in Fig. 5 represents an alternative rotor geometry within the hydrolift system and may be employed alone or in combination with blade-based rotary hydrofoil hydrolift systems on the same watercraft. In all such implementations, the rotor disc 502 functions as a lift-generating element of the hydrolift system and is configured to generate primary hydrodynamic lift sufficient to support at least aAttorney Docket No.: 2032-0011-PCTportion of the weight of the watercraft. In some implementations, the rotor disc 502 is configured to generate lift exceeding the weight of the watercraft during operation.

[0076] Fig. 6A and Fig. 6B illustrate a retractable hydrolift system implementation mounted to a watercraft 600. The hydrolift system includes a rotor 604 coupled to a rotor hoist 602, with the rotor hoist 602 being actuated by a first hydraulic arm 606 and a second hydraulic arm 608. The rotor 604 is mechanically coupled to a drive shaft and forms part of a hydrolift system as defined elsewhere herein.

[0077] Fig. 6A illustrates the hydrolift system in a deployed, operational position in which the rotor 604 is oriented generally downward and positioned below the watercraft 600 such that the rotor operates in water to generate hydrodynamic lift. In this position, rotation of the rotor 604 generates lift sufficient to support at least a portion of the weight of the watercraft 600, as described with respect to other hydrolift system implementations.

[0078] Fig. 6B illustrates the hydrolift system in a retracted position in which the hydraulic arms 606 and 608 reposition the rotor hoist 602 to rotate and raise the rotor 604 to a non-operational orientation. In the retracted position, the rotor 604 may be oriented sideways or upward and positioned closer to the hull of the watercraft 600. This configuration reduces exposure of the rotor 604 to debris, shallow water, or impact during docking, transport, or non-operational periods.

[0079] The hydraulic arms 606 and 608 may be independently or jointly actuated to control both the angular orientation and vertical position of the rotor hoist 602. Hinges and pivot joints associated with the rotor hoist 602 allow controlled rotation between the deployed and retracted positions. In some implementations, the hydraulic arms 606 and 608 may be replaced or supplemented by electric actuators, mechanical linkages, or other actuation mechanisms.

[0080] The retractable hydrolift system implementation shown in Figs. 6A and 6B enables selective deployment of lift-generating rotors only when required, improving operational flexibility, safety, and maintainability. In some implementations, the hydrolift system may be partially retracted during operation to adjust immersion depth of the rotor 604, thereby allowing control of lift magnitude, efficiency, or cavitation characteristics.

[0081] Multiple retractable hydrolift systems may be provided on a single watercraft 600, and the hydrolift control system may coordinate deployment, retraction, and operation of the systems individually or collectively.Attorney Docket No.: 2032-0011-PCT

[0082] As described in Figs. 6A and 6B above, the hydrolift system may be configured to be retractably mounted and movable between a deployed position and a retracted position, respectively.

[0083] Fig. 7 illustrates a hydrolift system implementation in which a rotary hydrofoil assembly is enclosed within a protective rotor screen. The hydrolift system is mounted to a watercraft 700 and includes an engine 702 coupled to a transmission 704, which drives a drive shaft 706 mechanically connected to a rotor 710. The rotor 710 forms part of the hydrolift system and is configured to generate hydrodynamic lift when rotated in water.

[0084] A rotor screen support 708 is mounted to the watercraft 700 and structurally supports a rotor screen 712 surrounding at least a portion (e.g., more than 1% of its planform area) of the rotor 710. The rotor screen 712 includes a high-porosity structure configured to permit water flow through the screen while providing a protective barrier between the rotor and external objects (e.g., debris, marine life, or foreign objects) in the water.

[0085] During operation, the engine 702 drives the rotor 710 through the transmission 704 and drive shaft 706 under control of the hydrolift control system. Rotation of the rotor 710 in water generates hydrodynamic lift sufficient to support at least a portion of the weight of the watercraft 700. The presence of the rotor screen 712 does not materially impede lift generation but provides mechanical protection and improved operational safety.

[0086] The rotor screen 712 may be formed from a mesh, lattice, grid, or perforated structure, and may be constructed from metal, composite, or polymer materials, or a combination of materials, selected for strength, corrosion resistance, and hydrodynamic performance. The rotor screen support 708 maintains structural spacing between the rotor 710 and the rotor screen 712 and may be configured to absorb impact loads or vibrations.

[0087] In some implementations, the rotor screen 712 is removable or hinged to allow access to the rotor 710 for inspection, maintenance, or replacement. In other implementations, the rotor screen 712 remains fixed during operation and non-operation. The screened hydrolift system implementation shown in Fig. 7 is particularly suited for environments with floating debris, shallow water, or marine life, and for applications where enhanced safety for nearby objects or personnel is desired.

[0088] Multiple screened hydrolift systems may be employed on a single watercraft 700, and the hydrolift control system may coordinate operation of the systems in the same manner as other hydrolift system implementations described herein.Attorney Docket No.: 2032-0011-PCT

[0089] Fig. 8A and Fig. 8B illustrate operational modes of a watercraft 800 equipped with one or more hydrolift systems, showing transition between lift-based operation and buoyancy-supported operation.

[0090] Fig. 8A illustrates the watercraft 800 in a lift-based operating mode in which a hydrolift system 802 is switched on. In this mode, the hydrolift system 802 is actively driven to generate hydrodynamic lift, raising the watercraft 800 above the surrounding water 806. Ihe lift generated by the hydrolift system 802 reduces or substantially eliminates contact between the hull of the watercraft 800 and the water 806, thereby reducing hydrodynamic drag during operation.

[0091] Fig. 8B illustrates the watercraft 800 in a non-lift operating mode in which the hydrolift system 804 is switched off. In this mode, the hydrolift system does not generate lift, and the watercraft 800 floats in the water 806 primarily by buoyancy. This configuration may be used during low-speed operation, docking, loading, unloading, maintenance, or when liftbased operation is not required.

[0092] The transition between the operating modes shown in Fig. 8A and Fig. 8B may be controlled by the hydrolift control system, which selectively activates or deactivates the hydrolift system based on operator input, operating conditions, or system constraints. The ability to switch between lift-based and buoyancy-supported operation enables flexible use of the watercraft 800 across a wide range of speeds, payloads, and environments.

[0093] In some implementations, partial activation of the hydrolift system may be employed to supplement buoyancy without fully lifting the watercraft 800 above the water 806. In other implementations, full lift-based operation may be employed to achieve maximum drag reduction and high-speed performance.

[0094] Fig. 9A and Fig. 9B illustrate an implementation of a watercraft 900 incorporating both hydrolift systems and auxiliary flotation devices to provide redundant support and safe operation across multiple operating conditions. The one or more auxiliary flotation devices or buoyant flotation devices may be housed on the watercraft, such that in response to the hydrolift being deactivated, the one or more buoyant flotation devices maintain flotation of the watercraft.

[0095] Fig. 9A illustrates the watercraft 900 in a lift-based operating mode in which a hydrolift system 902 is actively driven to generate hydrodynamic lift. In this mode, the hydrolift system 902 produces lift sufficient to raise the watercraft 900 above the surrounding water 904, thereby reducing or substantially eliminating contact between the hull and the water. The lift generated by the hydrolift system 902 is independent of forward translationalAttorney Docket No.: 2032-0011-PCTmotion or movement of the watercraft 900 and is controlled by the hydrolift control system as described elsewhere herein.

[0096] Fig. 9B illustrates the watercraft 900 in a buoyancy-supported operating mode in which the hydrolift system 906 is switched off or otherwise not generating lift and flotation is provided by flotation collars. In this mode, one or more flotation collars 908 arc deployed or inflated to provide buoyant support for the watercraft 900, allowing the watercraft to float safely in the water 904. The flotation collars 908 may be positioned around a perimeter of the watercraft 900 or at selected locations to provide stable buoyancy and maintain a desired attitude. In such implementations, when the hydrolift system is deactivated or otherwise not generating lift, the buoyant flotation devices maintain flotation of the watercraft in the water.

[0097] The flotation collars 908 may be inflatable, flexible, rigid, or semi-rigid structures and may be deployed automatically or manually. In some implementations, the flotation collars 908 are activated in response to detection of a fault condition, power loss, or shutdown of the hydrolift system. In other implementations, the flotation collars 908 are used during docking, maintenance, loading, unloading, or low-speed operation.

[0098] The implementation shown in Fig. 9B demonstrates a hybrid lift-and-buoyancy system in which the hydrolift system 902 provides primary lift during normal operation, while the flotation collars 908 provide redundant buoyant support when the hydrolift system 906 is inactive. This configuration enhances safety, reliability, and operational flexibility of the watercraft 900 across a wide range of operating conditions.

[0099] Fig. 10 illustrates a system-level architecture of a hydrolift system integrated with a watercraft. The system includes one or more energy sources and control components configured to power and regulate operation of one or more hydrolift systems mounted to the watercraft.[000100] A fuel source 1000 selected from a fuel source list 1002 supplies energy to an engine 1004 in implementations employing an internal combustion power source. The engine 1004 may operate on fuels including, but not limited to, diesel, natural gas, hydrogen, or other suitable fuels. In alternate implementations, a motor 1010 powered by batteries 1012 provides rotational power to the hydrolift system, either alone or in combination with the engine 1004. In yet other implementations, other types of prime movers may be used to provide power to the engine 1004.[000101] Power generated by the engine 1004 or motor 1010 is transmitted through a transmission 1006 to a hydrolift rotor 1008, which forms part of a hydrolift system as defined elsewhere herein. The transmission 1006 may include mechanical, electrical, orAttorney Docket No.: 2032-0011-PCTelectromechanical components configured to regulate torque and rotational speed delivered to the hydrolift rotor 1008.[000102] A hydro lift control system 1014 is operatively coupled to the engine 1004, motor 1010, transmission 1006, and hydrolift rotor 1008. The hydrolift control system 1014 executes control logic stored in a hydrolift control system list 1016 to regulate operation of the hydrolift systems. Control functions may include, without limitation, control of rotor rotational speed, rotor orientation, angle of attack, activation and deactivation of hydrolift systems, modulation of lift output, coordination among multiple hydrolift systems, and management of transitions between lift-based and buoyancy-supported operating modes.[000103] In some implementations, the hydrolift control system 1014 activates and deactivates the hydrolift system by gradually increasing or decreasing lift output to control transition dynamics between buoyancy-supported and lift-based operating modes. By gradually increasing or decreasing lift output, the transition may occur with minimum instability and in a controlled manner.[000104] The hydrolift control system 1014 is further configured to interface with watercraft navigation and control 1018. Through this interface, hydrolift system operation may be coordinated with watercraft vessel steering, propulsion, speed commands, and stability management. In some implementations, inputs from watercraft navigation and control 1018 are used to adjust lift distribution among multiple hydrolift systems to manage pitch, roll, and heave of the watercraft. In some implementations, the hydrolift control system 1014 regulates both lift forces and drag forces acting on the watercraft by adjusting rotor rotational speed, rotor orientation, and blade angle of attack.[000105] In some implementations, the hydrolift control system 1014 may receive feedback indicative of the state of the watercraft. The state may include operating conditions of the watercraft or other information such as watercraft attitude, load conditions, etc. The hydrolift control system 1014 may adjust the operation of the hydrolift system in response to the received feedback. The feedback may be transmitted to the hydrolift control system by one or more sensors on the watercraft, by an input device, by user instructions, etc.[000106] The architecture shown in Fig. 10 supports a modular hydrolift system in which multiple hydrolift systems may be controlled individually or collectively, powered by one or more energy sources, and integrated with existing watercraft control systems. This system-level configuration enables scalable deployment of hydrolift systems across a wide range of watercraft sizes and operating conditions.Attorney Docket No.: 2032-0011-PCT[000107] In some implementations, a single hydrolift control system is configured to control operation of multiple hydrolift systems mounted to a watercraft. In other implementations, respective hydrolift systems include associated control systems that communicate with one another in a distributed control arrangement to coordinate lift generation, stability control, and operational behavior among the hydrolift systems.[000108] In some implementations where multiple hydrolift systems are implemented, various different hydrolift systems mounted to a single watercraft may be operated with different rotor orientations to influence overall vessel motion.[000109] Fig. 11 is a flowchart of a method of operating a watercraft equipped with one or more hydrolift systems to generate hydrodynamic lift and control watercraft motion. The hydrolift system may be any system described above.[000110] At step 1100, a watercraft having one or more installed hydrolift systems is provided in water.[000111] In this initial condition, the watercraft may be stationary or moving at low speed, and the hydrolift systems are mounted to the watercraft as described elsewhere herein.[000112] In such implementations, the hydro lift systems are retractably mounted to the watercraft such that the rotor may be selectively positioned and moveable in a deployed position for lift generation or a retracted position for reduced exposure.[000113] At step 1102, when the hydrolift systems are not active, the watercraft floats in the water using natural buoyancy. In this state, the weight of the watercraft is supported primarily or entirely by buoyant forces acting on the hull, and the hydrolift systems do not generate lift.[000114] At step 1104, one or more hydrolift systems are activated. Upon activation, the hydrolift systems generate hydrodynamic lift that acts on the watercraft. The lift is generated by actively rotating one or more rotors of the hydrolift systems in the water, producing relative motion between the rotors and the surrounding water. The lift generated at this step is independent of forward translational motion or movement of the watercraft. Thus, the hydrodynamic lift is generated by rotation of the rotor relative to the surrounding water, rather than by forward motion of the watercraft.[000115] At step 1106, operational parameters of the hydrolift systems are actively controlled to stabilize the watercraft in the water. Control parameters include rotational speed of the rotors, angle of attack of hydrofoil blades where applicable, and rotor orientation of the hydrolift systems. These parameters are regulated by one or more hydrolift control systems to maintain a desired lift magnitude and watercraft attitude.Attorney Docket No.: 2032-0011-PCT[000116] At step 1108, the hydrolift systems interact with guidance systems of the watercraft. Operator instructions or autonomous navigation commands are converted into specific control operations of the hydrolift systems, including adjustments to lift distribution, rotor speed, blade angle of attack, or orientation, in order to achieve a desired effect such as forward motion, maneuvering, or stability control.[000117] At step 1110, the hydrolift systems are deactivated or operated at reduced output, terminating or reducing lift generation. As a result, the watercraft transitions from liftbased operation back to buoyancy-supported flotation, with the hull again being supported primarily by buoyant forces in the water.[000118] At step 1112, the method further includes installing more than one hydrolift system on a single watercraft and maintaining communication between the hydrolift systems. The hydrolift systems are coordinated through one or more control systems to ensure that required operational behavior is achieved, including balanced lift generation, stability control, and coordinated response to guidance or operator inputs.[000119] Fig. 12 is a flowchart illustrating an example method of operating a watercraft in which a hydrolift system is activated to rotate a rotor in water to generate hydrodynamic lift and selectively transition the watercraft between buoyancy-supported flotation and liftbased flotation.[000120] At step 1210, a watercraft having one or more hydrolift systems is provided in water.[000121] At step 1220, in response to the one or more hydrolift systems being inactive, the watercraft is supported in the water by buoyancy.[000122] At step 1230, at least one hydrolift system mounted to the watercraft is activated.[000123] At step 1240, a rotor of the at least one hydrolift system in the water is rotated to generate hydrodynamic lift that is independent of forward translational motion or movement of the watercraft.[000124] At step 1250, operation of the at least one hydrolift system is controlled using a hydrolift control system to regulate lift output such that the watercraft transitions from a buoyancy-supported flotation state to a lift-based flotation state in which hydrodynamic lift generated by the rotor supports at least a portion of a weight of the watercraft.[000125] At step 1260, operation of the at least one hydrolift system is deactivated to allow the watercraft to return to buoyancy-supported flotation. The hydrolift system may be partially deactivated or operated at reduced power.Attorney Docket No.: 2032-0011-PCT[000126] In some implementations, controlling operation of the at least one hydrolift system includes adjusting at least one of rotor rotational speed, blade angle of attack, or rotor orientation to regulate the hydrodynamic lift.[000127] In some implementations, generating hydrodynamic lift reduces contact between a hull of the watercraft and the surrounding water during operation in response to the watercraft being stationary or in translational motion.[000128] In some implementations, multiple hydrolift systems mounted to the watercraft are operated. Operation of the hydrolift systems to control at least one of pitch, roll, or heave of the watercraft is coordinated.[000129] In some implementations, an orientation of a rotational axis of the rotor, the rotor orientation, is adjusted such that rotation of the rotor in water produces both lift and thrust components acting on the watercraft.[000130] In some implementations, in response to deactivation of the hydrolift system, flotation of the watercraft is maintained using one or more buoyant flotation devices provided on the watercraft.[000131] The methods illustrated in Figs. 11 and 12 may be performed using bladebased rotary hydrofoil hydrolift systems, disc-based hydrolift systems, or combinations thereof. The steps of the method may be executed sequentially, concurrently, or repeatedly during operation of the watercraft.[000132] In some implementations, the methods may be performed while the watercraft is stationary prior to activation of the hydrolift systems.[000133] Fig. 13 describes a basic control loop of the hydrolift control system. When the hydrolift system is turned on, in the first step 1300, it receives instructions from the operator. The operator may be the watercraft operator, the watercraft guidance and navigation system, or an embedded logic.[000134] At step 1310, the hydrolift control system calculates an initial setting for control parameters of the hydrolift system, such as the RPM, blade angle-of-attack, and the rotor orientation, using the instructions and sensor data. The selected parameter settings are implemented by the hydrolift system which generates physical feedback.[000135] At step 1320, the hydrolift control system receives feedback from sensors associated with the watercraft and in communication with the hydrolift control system. The hydrolift control system receives commands or reference data from a watercraft guidance and navigation system indicative of desired operating conditions, and adjusts operation of the hydrolift system based on difference between the current and desired operating conditions. InAttorney Docket No.: 2032-0011-PCTsome implementations, the hydrolift control system may receive feedback indicative of watercraft state and adjust operation accordingly.[000136] At step 1330, based on the difference between current operating conditions and desired operating conditions, hydrolift control parameters are adjusted to bring the operating conditions closer to desired operating conditions. Operating conditions include lift force, which dictates submergence level, forward velocity, watercraft stability, and other factors relevant for safe, stable, and economic performance of the watercraft.[000137] Fig. 14 depicts the rotor orientation of the hydrolift system. The watercraft 1402 with an engine 1400 has a hydrolift system 1408 mounted to it via a transmission 1404 which delivers mechanical power from the engine 1400 to the hydrolift system. The hydrolift system 1408 includes the drive shaft 1406 and rotor blades 1407. Fig. 14 also shows a vertical line 1410 perpendicular to the watercraft base 1416. The rotor plane line 1412 is a line parallel to the plane of the rotor blades 1407. The angle between the vertical line 1410 and rotor plane line 1412 is the angle of rotor orientation 1414. This angle may be 90 degrees, in which case the rotor blades 1407 draw a circle that is in a plane parallel to the watercraft base 1416. In other implementations, this angle may be greater than or less than 90 degrees, but greater than 0 degrees. This angle determines the rotor orientation which is a parameter controlled by the hydrolift control system.[000138] The rotor orientation (also referred to as the angle of rotor orientation 1414) influences the magnitude and direction of the resultant force that the hydrolift system 1408 generates while its rotor 1407 is rotating in water. Varying the rotor orientation, changes the lift, thrust, and drag that the watercraft 1402 experiences from the hydrolift system 1408. In some implementations, the drive shaft 1406 itself may be tilted with respect to the watercraft base 1416, resulting in the same effect of creating an angle of rotor orientation 1414 which is not 90 degrees.[000139] In some implementations, by adjusting rotor orientation, the hydrolift system may generate force components acting in both upward and non-vertical directions.[000140] As described above, the hydrolift systems described herein differs from conventional marine propulsion and flotation technologies. Unlike conventional marine propulsion and stabilization systems, the hydrolift systems described herein are configured to generate hydrodynamic lift as a primary mechanism for supporting a watercraft in the water, rather than as an incidental or auxiliary effect of propulsion. In conventional propeller-based, or thruster-based systems, rotating underwater components are operated primarily to generate thrust, with any lift forces being secondary, incidental, or used for limited stabilizationAttorney Docket No.: 2032-0011-PCTpurposes. Similarly, fixed hydrofoil systems rely on forward translational motion of the watercraft to generate lift and are therefore ineffective at zero or low speeds.[000141] In contrast, the hydrolift systems described herein generate hydrodynamic lift through active rotation of hydrofoil blades in water, such that lift is produced by relative motion between the rotating rotor and the surrounding water and docs not depend on forward translational motion of the watercraft. This configuration enables selective operation between a buoyancy-supported flotation state and a lift-based flotation state, in which hydrodynamic lift generated by the hydrolift system supports the watercraft independently of hull speed. As a result, the hydrolift system provides a fundamentally different operational role than conventional propulsion or hydrofoil technologies.[000142] Furthermore, the hydrolift system provides operational capabilities not available to conventional watercraft, including lift-based flotation independent of forward translational motion. By lifting the watercraft out of water, the rotary hydrofoil assembly enables a significant advantage, which is the ability to avoid the form drag of water on the watercraft, while benefiting from the very high lift force of water (about 1000 times higher than air). As a result, the watercraft faces form drag primarily from air (about 1000 times less than water for same planform area), while generating lift from water.[000143] This allows watercrafts to achieve much lower drag losses in some conditions. This in turn enables much higher fuel efficiency, even after factoring in induced drag from the spinning hydrofoils. Similarly, it allows the watercraft to operate at much higher velocities than conventional buoyancy lifted watercraft due to potentially reduced drag at high velocities.[000144] Additionally, such a watercraft can be substantially more maneuverable than conventional buoyancy driven watercrafts.[000145] The words “example” or “exemplary” are used herein to mean serving as an example, instance, or illustration. Any aspect or design described herein as “example’ or “exemplary” is not necessarily to be construed as preferred or advantageous over other aspects or designs. Rather, use of the words “example” or “exemplary” is intended to present concepts in a concrete fashion. As used in this application, the term “or” is intended to mean an inclusive “or” rather than an exclusive “or”. That is, unless specified otherwise, or clear from context, “X includes A or B” is intended to mean any of the natural inclusive permutations. That is, if X includes A; X includes B; or X includes both A and B, then “X includes A or B” is satisfied under any of the foregoing instances. In addition, the articles “a” and “an” as used in this application and the appended claims should generally be construed toAttorney Docket No.: 2032-0011-PCTmean “one or more” unless specified otherwise or clear from context to be directed to a singular form. Moreover, use of the term “an embodiment” or “one embodiment” or “an implementation” or “one implementation” throughout is not intended to mean the same embodiment or implementation unless described as such.[000146] Reference throughout this specification to “one embodiment” or “an embodiment” means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, the appearances of the phrase “in one embodiment” or “in an embodiment” in various places throughout this specification are not necessarily all referring to the same embodiment. In addition, the term “or” is intended to mean an inclusive “or” rather than an exclusive “or.” [000147] It is to be understood that the above description is intended to be illustrative, and not restrictive. Many other embodiments will be apparent to those of skill in the art upon reading and understanding the above description. The scope of the disclosure should, therefore, be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled.

Claims

Attorney Docket No.: 2032-0011-PCTClaimsWhat is claimed is:

1. A hydrolift system for generating hydrodynamic lift for a watercraft, the hydrolift system comprising:a rotor configured to operate in water, the rotor configured to, in response to being rotated, generate hydrodynamic lift;a drive shaft mechanically coupled to the rotor, the drive shaft configured to transmit rotational power to the rotor; anda hydrolift control system operatively coupled to the drive shaft and the rotor, the hydrolift control system configured to control operation of the rotor and the drive shaft; wherein rotation of the rotor in water generates hydrodynamic lift, wherein the hydrodynamic lift is independent of forward translational motion or movement of the watercraft; andwherein the hydrolift control system is further configured to regulate lift output of the hydrolift system such that the watercraft is selectively operable in a buoyancy-supported flotation state and a lift-based flotation state in which the hydrodynamic lift generated by the rotor supports at least a portion of a weight of the watercraft.

2. The hydrolift system of claim 1, wherein the rotor comprises a rotor head and a plurality of hydrofoil blades extending radially from the rotor head, the rotor being configured for rotary motion in water to generate lift.

3. The hydrolift system of claim 1, wherein the rotor comprises a rotor disc configured to generate the hydrodynamic lift in response to being rotated in water.

4. The hydrolift system of claim 1, wherein the hydrolift control system is configured to regulate the hydrodynamic lift by controlling at least one of rotor rotational speed, blade angle of attack, or rotor orientation.

5. The hydrolift system of claim 1, wherein the hydrodynamic lift generated by the rotor is configured to reduce contact between a hull of the watercraft and the water during operation in response to the watercraft being either stationary or in translational motion.

6. The hydrolift system of claim 1, wherein the hydrolift system is configured to be retractably mounted and movable between a deployed position and a retracted position.

7. The hydrolift system of claim 1, further comprising a protective rotor screen configured to allow water flow, wherein the protective rotor screen further provides a protective barrier between the rotor and external objects in the water.Attorney Docket No.: 2032-0011-PCT8. The hydrolift system of claim 1, wherein the hydrolift control system is configured to coordinate operation of a plurality of hydrolift systems mounted to the watercraft to control stability of the watercraft.

9. The hydrolift system of claim 8, wherein the hydrolift control system is configured to coordinate operation of the plurality of hydrolift systems to control at least one of pitch, roll, or heave of the watercraft.

10. The hydrolift system of claim 1, wherein the hydrolift system is configured to operate in combination with one or more buoyant flotation devices housed on the watercraft, such that in response to the hydrolift being deactivated, the one or more buoyant flotation devices maintain flotation of the watercraft.

11. The hydrolift system of claim 1 , wherein the hydrolift control system is configured to adjust at least one of rotor rotational speed, rotor orientation, or blade angle of attack to regulate lift and drag forces in view of watercraft mass and operating conditions.

12. The hydrolift control system of claim 8 wherein the hydrolift control system comprises one of:a controller configured to control a plurality of hydrolift systems, ora plurality of distributed controllers associated with respective hydrolift control systems and configured to communicate with one another to coordinate operation of the hydrolift control systems.

13. The hydrolift control system of claim 1 , wherein the rotor is coupled to a mounting structure configured to adjust an orientation of a rotational axis of the rotor to provide lift and thrust components in response to the rotor being rotated in water.

14. The hydrolift control system of claim 1, further comprising a power source operatively coupled to the drive shaft through a power transmission assembly, wherein the power source comprises at least one of an engine or a motor.

15. A method of operating a watercraft comprising:providing a watercraft having one or more hydrolift systems in water;in response to the one or more hydrolift systems being inactive, supporting the watercraft in the water by buoyancy;activating at least one hydrolift system mounted to the watercraft;rotating a rotor of the at least one hydrolift system in the water to generate hydrodynamic lift that is independent of forward translational motion or movement of the watercraft:Attorney Docket No.: 2032-0011-PCTcontrolling operation of the at least one hydrolift system using a hydrolift control system to regulate lift output such that the watercraft transitions from a buoyancy- supported flotation state to a lift-based flotation state in which hydrodynamic lift generated by the rotor supports at least a portion of a weight of the watercraft; anddeactivating operation of the at least one hydrolift system to allow the watercraft to return to buoyancy-supported flotation.

16. The method of claim 15, wherein controlling operation of the at least one hydrolift system comprises adjusting at least one of rotor rotational speed, blade angle of attack, or rotor orientation to regulate the hydrodynamic lift.

17. The method of claim 15, wherein generating hydrodynamic lift reduces contact between a hull of the watercraft and surrounding water during operation in response to the watercraft being stationary or in translational motion.

18. The method of claim 15, further comprising operating a plurality of hydrolift systems mounted to the watercraft and coordinating operation of the plurality of hydrolift systems to control at least one of pitch, roll, or heave of the watercraft.

19. The method of claim 15, further comprising adjusting an orientation of the rotor such that rotation of the rotor in water produces both lift and thrust components acting on the watercraft.

20. The method of claim 15, further comprising, in response to deactivation of the hydrolift system, maintaining flotation of the watercraft using one or more buoyant flotation devices provided on the watercraft.

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