Multi-mode electric watercraft

Abstract

An electric watercraft includes a main foil subassembly with a fully submersible hydrofoil and a propulsion subassembly with a thruster comprising an electric motor and a propeller. The main foil and propulsion subassemblies each include at least one adjustable vertical strut to adjust the respective depths of the hydrofoil and the thruster in the water. The adjustable struts allow the watercraft to seamlessly transition between multiple modes of operation to accommodate a variety of sea states. The watercraft may further include airfoils and / or an aerodynamically shaped body to facilitate a wing-in-ground effect (WIGE), which provides a lifting force to raise the body above the water. This allows the hydrofoil to operate at a lower angle of attack, resulting in less hydrodynamic drag. Battery modules may be disposed within or on the vertical struts to lower the center of gravity of the watercraft, thus improving stability.

Description

MULTI-MODE ELECTRIC WATERCRAFTCROSS-REFERENCE TO RELATED APPLICATION(S)

[0001] This application claims the priority benefit, under 35 U.S.C. 119(e), of U.S. Application No. 63 / 585,374, filed September 26, 2023 and entitled, “Multi-Mode Electric Watercraft,” which is incorporated herein by reference in its entirety.BACKGROUND

[0002] A variety of conventional watercraft as well as conventional sea planes respectively employing hydrofoils and / or aerodynamic lifting features (e.g., airfoils) have been described in the prior art. An exemplary list of publications generally relating to such vessels or vehicles includes U.S. Pat. Nos. 1,307,135, 2,343,645, 3,064,370, 3,157,146, 3,485,198, 3,918,382, 4,080,922, 4,237,810, 4,452,166, 4,955,312, 4,964,357, 5,018,686, 5,544,607, 5,813,358, 6,014,940, 6,073,569, 6,199,496, 6,230,835, 6,546,886, 6,990,918, 7,188,580, 8,453,591, 10,099,754, 10,377,447, and 10,532,793, U.S. Pub. Nos. 2007 / 0245943, 2022 / 0355902, and 2023 / 0033965, PCT Pubs. W02022010402, W02022010404, WO2023135289, and WO2023135290, and Swedish Pub. SE1751183.SUMMARY

[0003] The present disclosure relates generally to electric watercraft for transporting passengers relatively short distances on coastal and inland waters safely, comfortably and efficiently in a variety of sea conditions (“sea states”). In some illustrative examples provided herein, one implementation of an electric watercraft is a relatively small craft (e.g., targeted to individual owners with conventional small craft basic safety training) that can be used for recreational purposes but also provides rapid, comfortable, and affordable point-to-point transport over water as an alternative to transport over land. The various examples of watercraft disclosed herein feature architectural and design innovations that provide significant advances in performance, ride experience, and energy efficiency (e.g., powered by electric motors rather than internal-combustion engines). Although some examples contemplate relatively smaller watercraft, one of ordinary skill in the art would readily appreciate that the inventive concepts disclosed herein can be applied generally to different sizes and configurations of watercraft.

[0004] As discussed in further detail herein, in example implementations the disclosed watercraft are “multi-mode” electric watercraft in that they are configured to be capable of multiple operating modes given different sea conditions during travel over water. By seamlessly transitioning amongst multiple modes of operation and, thus, being adaptable tovarying sea conditions, the electric watercraft disclosed herein enable an expanded range of energy efficient, safe and comfortable sea travel opportunities for watercraft of various sizes and purposes.

[0005] As would be appreciated by those of ordinary skill in the relevant arts, “sea state” typically refers to the overall condition of the sea surface in terms of wave height, wave frequency, and wave patterns caused by local wind-generated waves at a certain location and moment in time. Sea state is primarily influenced by wind speed, wind duration, and fetch (the distance over which wind blows across the water). “Swell” generally refers to waves that have traveled away from their area of origin and can be the result of distant weather systems or storms. Often, when trained mariners and oceanographers refer to "sea state," they are considering the immediate conditions of the sea in a given area, which would include both the local wind-generated waves as well as any swell that might be present. Accordingly, from the perspective of one of ordinary skill in the art in the context of the present disclosure, “sea state” includes both local wind-generated waves and swell when considering the overall condition of the sea surface at a certain location and moment in time (it should be appreciated, however, that in some specific technical or maritime engineering contexts, the term "sea state" might be used to specifically describe the locally generated waves by wind, and swell might be discussed separately).

[0006] As also would be appreciated by one of ordinary skill in the art, “sea state” and “turbulence” are related concepts in the context of the ocean, but they are not the same thing. They both refer to the movement and behavior of water in the ocean, but they have distinct meanings and implications. While sea state refers to the physical condition of the water surface in terms of its appearance and behavior due to waves and wind, turbulence on the other hand refers to the chaotic and irregular movement of fluid (in this case, seawater) caused by the interaction of different flows, currents, and forces. Turbulence involves the mixing of fluid properties like temperature, salinity, and momentum in a complex manner. It is characterized by fluctuations in velocity, pressure, and other physical properties. Turbulence in the ocean can arise from various sources, including wind, tidal forces, currents, and interactions with the seafloor.

[0007] While turbulence is a key factor contributing to the generation and behavior of waves (thus influencing sea state), it is not the only factor. As noted above, waves can also be influenced by factors like swell from distant storms and seafloor topography. Turbulence plays a role in the interaction between water layers, mixing of nutrients and heat, and the overalldynamics of the ocean, but it may not always be directly visible at the water surface like sea state. Thus, sea state pertains to the appearance of the ocean's surface due to wave action, while turbulence involves the complex, often invisible, movement and mixing of water masses beneath the surface.[0008| Sea state is often categorized using a graded scale that includes some number of grades or other descriptors; such grades or descriptors range from a grade / descriptor for relatively calm conditions to a grade / descriptor for extremely rough conditions. Two examples of graded scales used to describe sea state include the Beaufort Wind Scale and the Douglas Sea Scale. Generally speaking, the Beaufort Wind Scale tends to be more commonly used by trained mariners and oceanographers to describe sea state as compared to the Douglas Sea Scale.[0009} The Beaufort Wind Scale, developed by Sir Francis Beaufort in the early 19th century, is a widely recognized system for estimating wind speed and its effects on the sea's surface. It provides descriptions of sea conditions at various wind speeds, ranging from calm to hurricane force. The Beaufort Wind Scale is reproduced below, in which “Force” is often referred to alternatively as “Beaufort Number”:

[0010] The Beaufort Wind Scale is a commonly-used measure in oceanography and with trained mariners that provides a general assessment of sea conditions encompassing the combined effects of wind-generated waves and other factors like swell. For example, the scale's descriptions include observations of wave crests breaking, whitecaps forming, and foam being blown in streaks. These observations can give an indication of both wind-generated waves and the presence of swell.[OOH] The Douglas Sea Scale is a system developed by Rear Admiral H.P. Douglas in the mid-20th century. It focuses on describing the state of the sea based on wave height and wave conditions, rather than directly correlating with wind speed. The Douglas Sea Scale includes nine grades (as opposed to the twelve grades on the Beaufort Wind Scale) that are used to characterize wind sea waves and swell, respectively:

[0012] The Douglas Sea Scale is provided above for illustration and completeness, and it is used around the world for certain applications; however, as noted above, the Beaufort Wind Scale generally is more commonly used by trained mariners and oceanographers.

[0013] Measuring sea state is important for maritime safety, weather forecasting, oceanographic research, and various other applications. Sea state can be measured using a variety of methods and instruments, examples of which include, but are not limited to, the following:[00.14] Buoy-Based Measurements:

[0015] Buoy systems equipped with sensors can provide real-time data on wave height, period, direction, and frequency. These buoys are often part of networks such as the National Data Buoy Center (NDBC) in the United States. They use accelerometers, pressure sensors, and other instruments to measure the motion of the buoy and the pressure exerted by passing waves.

[0016] Ship Observations:[00.17] Ships at sea often report observations of sea state, including wave height, direction, and appearance, as part of routine maritime operations. These reports contribute to weather and oceanographic databases.

[0018] Remote Sensing Satellites:

[0019] Satellite-based remote sensing techniques, such as Synthetic Aperture Radar (SAR), can provide information about sea surface roughness, which is related to sea state. SAR images can reveal the spatial patterns and distribution of waves on the ocean's surface.

[0020] Coastal Radar Systems:

[0021] Coastal radar systems can track the movement of waves as they approach the shore. These systems can provide information about wave height, direction, and speed.

[0022] Wave Rider Buoys:

[0023] Wave rider buoys, also known as Datawell buoys, are specialized buoys that are designed to directly measure wave characteristics. They use accelerometers to measure the vertical motion of the buoy, which is used to calculate wave properties.

[0024] Laser Sensors:

[0025] Laser-based sensors, such as LiDAR (Light Detection and Ranging), can be used to measure wave heights and slopes by analyzing the reflections of laser beams off the water surface.

[0026] Aircraft Observations:

[0027] Research aircraft can fly over the ocean and use instruments like radar altimeters to measure wave characteristics from above.]0028] Acoustic Instruments:

[0029] Acoustic instruments, such as Acoustic Doppler Current Profilers (ADCPs), can provide information about the velocity of currents and waves in the water column.

[0030] These methods can be used individually or in combination to provide a comprehensive understanding of sea state conditions in different oceanic regions. The data collected from these measurements contribute to weather models, oceanographic research, and maritime safety efforts.

[0031] Multi-mode Operation of Electric Watercraft

[0032] Regarding the multi-mode operation of the inventive electric watercraft disclosed herein, in one non-limiting example a multi-mode electric watercraft is configured to be operated in at least five different modes, namely:

[0033] 1) a wing-in-surface-effect (WISE) foiling mode (also referred to herein as wing-in- ground effect or WIGE) in the presence of sufficiently calm or smooth sea states (e.g., waves of less than 2 feet or 0.5 meters, wind speed of less than or equal to 6 knots; Beaufort number 0 - 2);

[0034] 2) an elevated foiling mode in the presence of slight or moderate sea states (e.g., waves of from about 2 feet to 6 feet, or 0.5 meters to 2 meters; wind speed of from about 7 knots to 16 knots; Beaufort number 3 - 4);

[0035] 3) a displacement mode in the presence of rough sea states (e.g., waves of from about 6 feet to 9 feet, or 2 meters to 3 meters; wind speed of from 17 knots to 21 knots; Beaufort number 5) and when the watercraft is departing from and arriving at a land interface;

[0036] 4) a stability (emergency) mode in the presence of very rough, high or very high sea states (e.g., waves greater than 9 feet or 3 meters; wind speed above 21 knots; Beaufort number 6 or higher); and[(>037) 5) a park mode.

[0038] To facilitate multi-mode operation, the inventive electric watercraft according to the present disclosure are designed and configured with multiple features that, respectively and in combination, enhance aerodynamic and hydrodynamic performance, stability and energy efficiency of the watercraft.

[0039] For example, in one implementation, an electric watercraft includes a body to carry multiple passengers, a main foil subassembly, and a propulsion subassembly. The main foil subassembly includes a primary fully submersible (FS) hydrofoil to generate a lifting force as the hydrofoil moves through water. The propulsion subassembly includes one or more electric motors to directly drive one or more propellers to generate a propulsive force for the watercraft. The propulsion subassembly may also include a secondary FS hydrofoil (e.g., to facilitate balancing the weight of passengers and overall stability and performance of the watercraft). One or both of the main foil subassembly or the propulsion subassembly includes one or more adjustable vertical struts that are coupled to the body. These adjustable vertical struts transmit one or both of the lifting force or the propulsive force to the body, and they adjust a distance between the body and the hydrofoil and / or a distance between the body and the electric motor(s). In this manner, one or both of the hydrofoil or the electric motor(s) is / are controllable over at least two different nominal operating depths in the water below the body during operation of the watercraft. In some example implementations, the distance between the body and the hydrofoil and the distance between the body and the electric motor(s) respectively can be controlled via the adjustable vertical strut(s) over various operating depths in the water in an essentially continuous, dynamic, and reflexively responsive manner based on different sea states through which the watercraft is travelling.

[0040] In other aspects, the body of the electric watercraft has a shape to significantly reduce air resistance as the body moves through air in the elevated foiling mode, and has an underbody shape to significantly increase a ground-effect lift in the WISE foiling mode. In one example, the body of the watercraft is a catamaran body having two hulls connected by a bridge deck. Additionally, examples of multi-mode electric watercraft disclosed herein may include one or more controllable airfoils that controllably extend from, and retract into, the body; the presence of one or more airfoils in some examples (and / or particular body shapes for the electric watercraft) significantly enhance the wing-in-surface-effect and reduce lift-dependent drag.100411 Regarding a wing-in-surface-effect (WISE) (or wing-in-ground effect - WIGE) foiling mode, as would be appreciated by one of ordinary skill, the closer a wing operates to an external surface such as the ground or water, the less drag it experiences. Conventionally, an airfoil passing through air increases air pressure on the underside of the airfoil, while decreasing pressure across the top of the airfoil. The high and low pressures are maintained until they flow off the end of the airfoil, where they form vortices causing lift-induced drag (typically a significant portion of the drag affecting an aircraft). As the span of an airfoil is increased, induced drag is decreased and the efficiency of the airfoil is increased. However, WISE / WIGE similarly increases the efficiency of an airfoil without requiring an increase in span; in particular, operating the airfoil near a surface such as the water or the ground has the same effect as increasing the aspect ratio of the airfoil because the surface reduces or mitigates vortices from forming and expanding at the end of the airfoil. In view of the foregoing, examples of the electric watercraft disclosed herein operate in a WISE foiling mode when sea conditions permit (e.g., sufficiently calm or smooth sea states) to realize significantly increased efficiency.

[0042] Examples of electric watercraft disclosed herein also include one or more sensors to measure a sea state of the water through which the watercraft is operating, and a controller to operate the watercraft based on the measured sea state of the water. In some examples, the controller governs operation of the one or more vertical struts (e.g., to change a depth in the water of the hydrofoil and / or electric motor(s) / propeller(s)), as well as other controllable features of the watercraft (e.g., the propelling force of the electric motor(s) / propeller(s); the span of one or more airfoils, the angle of attack of one or more of the primary or secondary hydrofoil(s)), to operate the watercraft in one of four modes, namely: a wing-in-surface-effect (WISE) foiling mode in the presence of calm or smooth sea states; an elevated foiling mode in the presence of slight or moderate sea states; a displacement mode in the presence of rough sea states and when the watercraft is departing from and arriving at a land interface; and an emergency mode in the presence of very rough, high or very high sea states.[0043| Another salient feature of the multi-mode electric watercraft disclosed herein relates to the positioning of batteries and battery modules in / on the electric watercraft. In one aspect, particular positioning of the batteries / battery modules in / on the watercraft relates at least in part to design considerations that affect a center of gravity (CG) of the watercraft so as to enhance stability and / or efficiency.

[0044] As would be appreciated by one of ordinary skill in the art, the center of gravity (CG) of a watercraft is an important parameter that influences the watercraft’s stability and handling characteristics on the water. The CG represents a point at which the entire weight of the watercraft and its contents is concentrated and considered to act vertically downward. The position of the CG can significantly affect a watercraft's stability; a CG that is relatively lower (e.g., further below the waterline / deeper into the water) typically results in greater stability, while a relatively higher CG can reduce stability and increase the risk of capsizing. The CG can change as cargo is loaded, fuel is consumed (e.g., in the case of engines burning fossil fuels), and passengers move around the watercraft; accordingly, designer and builders carefully consider the placement of components and cargo (including passengers) to ensure that the CG of a watercraft is appropriate for ensuring safe travelling, particularly in adverse weather conditions.

[0045] In view of the foregoing, and in further consideration of an electric watercraft and its power requirements, the Inventor has recognized and appreciated that battery placement in / on the electric watercraft is a salient design consideration. Accordingly, in some examples, the electric watercraft disclosed herein includes one or more battery modules that are mounted to and / or disposed in the main foil subassembly and / or the propulsion subassembly. As noted above, during multiple operating modes of the watercraft, these subassemblies generally are disposed further below the waterline / deeper into the water than the body of the watercraft (e.g., via one or more adjustable vertical struts). Accordingly, placement of the power source(s) for the electric watercraft in one or more of these subassemblies contributes to a relatively lower CG of the watercraft.

[0046] In one aspect, a given battery module may include one or more rechargeable batteries that provide power for generation of the propulsive force by the electric motor(s) / propeller(s). In one example, one or more of the vertical struts includes one or more cavities, and one or more battery modules may be contained in a given cavity of a vertical strut. Such a cavity further may have a particular form or shape such that the overall form or shape of at least the portion of the vertical strut surrounding the cavity reduces drag induced by the strut as it moves through the water.

[0047] It should be appreciated that all combinations of the foregoing concepts and additional concepts discussed in greater detail below (provided such concepts are not mutually inconsistent) are contemplated as being part of the inventive subject matter disclosed herein. In particular, all combinations of claimed subject matter appearing at the end of this disclosureare contemplated as being part of the inventive subject matter disclosed herein. It should also be appreciated that terminology explicitly employed herein that also may appear in any disclosure incorporated by reference should be accorded a meaning most consistent with the particular concepts disclosed herein.BRIEF DESCRIPTION OF THE DRAWINGS

[0048] The skilled artisan will understand that the drawings primarily are for illustrative purposes and are not intended to limit the scope of the inventive subject matter described herein. The drawings are not necessarily to scale; in some instances, various aspects of the inventive subject matter disclosed herein may be shown exaggerated or enlarged in the drawings to facilitate an understanding of different features. In the drawings, like reference characters generally refer to like features (e.g., functionally similar and / or structurally similar elements).

[0049] FIG. 1A shows a top view of an example watercraft with battery modules disposed within one or more storage sections integrally formed in a strut and an extended canopy. The watercraft is shown in displacement mode.

[0050] FIG. IB shows a side view of the watercraft of FIG. 1A.

[0051] FIG. 1C shows a front view of the watercraft of FIG. 1 A.

[0052] FIG. 2A shows a top view of the watercraft of FIG. 1 A in ground effect mode.

[0053] FIG. 2B shows a side view of the watercraft of FIG. 2A.

[0054] FIG. 2C shows a front view of the watercraft of FIG. 2 A.

[0055] FIG. 3A shows a top view of the watercraft of FIG. 1 A in elevation mode.

[0056] FIG. 3B shows a side view of the watercraft of FIG. 3 A.

[0057] FIG. 3C shows a front view of the watercraft of FIG. 3A.

[0058] FIG. 4A shows a top view of the watercraft of FIG. 1 A in emergency mode.

[0059] FIG. 4B shows a side view of the watercraft of FIG. 4A.

[0060] FIG. 4C shows a front view of the watercraft of FIG. 4 A.

[0061] FIG. 5 A shows a top view of the watercraft of FIG. 1 A in park mode.

[0062] FIG. 5B shows a side view of the watercraft of FIG. 5 A.

[0063] FIG. 5C shows a front view of the watercraft of FIG. 5A.

[0064] FIG. 6A shows a side view of a rear strut in the watercraft of FIG. 1 A containing multiple battery modules.

[0065] FIG. 6B shows a front view of the rear strut of FIG. 6 A.

[0066] FIG. 6C shows a perspective view of the rear strut of FIG. 6A.

[0067] FIG. 7A shows a top view of an example watercraft with battery modules stored within a torpedo-shaped storage section coupled to a strut and a windshield. The watercraft is shown in displacement mode.

[0068] FIG. 7B shows a side view of the watercraft of FIG. 7A.

[0069] FIG. 7C shows a front view of the watercraft of FIG. 7A.

[0070] FIG. 8 A shows a top view of the watercraft of FIG. 7 A in ground effect mode.

[0071] FIG. 8B shows a side view of the watercraft of FIG. 8 A.

[0072] FIG. 8C shows a front view of the watercraft of FIG. 8 A.

[0073] FIG. 9A shows a top view of the watercraft of FIG. 7A in elevation mode.

[0074] FIG. 9B shows a side view of the watercraft of FIG. 9A.

[0075] FIG. 9C shows a front view of the watercraft of FIG. 9 A.

[0076] FIG. 10A shows a top view of the watercraft of FIG. 7 A in stability mode.

[0077] FIG. 10B shows a side view of the watercraft of FIG. 10 A.

[0078] FIG. 10C shows a front view of the watercraft of FIG. 10A.

[0079] FIG. 11 A shows a top view of an example watercraft with battery modules stored within a torpedo-shaped storage section coupled to a strut and an extended canopy. The watercraft is shown in displacement mode.

[0080] FIG. 1 IB shows a side view of the watercraft of FIG. 11 A.

[0081] FIG. 11C shows a front view of the watercraft of FIG. 11 A.DETAILED DESCRIPTION

[0082] Following below are more detailed descriptions of various concepts related to, and implementations of, multi-mode electric watercraft. It should be appreciated that various concepts introduced above and discussed in greater detail below may be implemented in multiple ways. Examples of specific implementations and applications are provided primarilyfor illustrative purposes so as to enable those skilled in the art to practice the implementations and alternatives apparent to those skilled in the art.

[0083] The figures and example implementations described below are not meant to limit the scope of the present implementations to a single embodiment. Other implementations are possible by way of interchange of some or all of the described or illustrated elements. Moreover, where certain elements of the disclosed example implementations may be partially or fully implemented using known components, in some instances only those portions of such known components that are necessary for an understanding of the present implementations are described, and detailed descriptions of other portions of such known components are omitted so as not to obscure the present implementations.

[0084] In the discussion below, various examples of a multi-mode electric watercraft are provided, wherein a given example or set of examples showcases one or more features of the watercraft. It should be appreciated that one or more features discussed in connection with a given example may be employed in other examples of watercraft according to the present disclosure, such that the various features disclosed herein may be readily combined in a given watercraft according to the present disclosure (provided that respective features are not mutually inconsistent).

[0085] Certain dimensions and features of the system and its components and / or subsystems are described herein using the terms “approximately,” “about,” “substantially,” and / or “similar.” As used herein, the terms “approximately,” “about,” “substantially,” and / or “similar” indicates that each of the described dimensions or features is not a strict boundary or parameter and does not exclude functionally similar variations therefrom. Unless context or the description indicates otherwise, the use of the terms “approximately,” “about,” “substantially,” and / or “similar” in connection with a numerical parameter indicates that the numerical parameter includes variations that, using mathematical and industrial principles accepted in the art (e.g., rounding, measurement or other systematic errors, manufacturing tolerances, etc.), would not vary the least significant digit.

[0086] 1. An Example Watercraft with Battery Modules Disposed in Struts

[0087] FIGS. 1A-5C show several views of an example watercraft 100a in various modes of operation. As shown, the watercraft 100a includes a body 110, a main foil subassembly 130 movably coupled to the body 110, and a propulsion subassembly 150 movably coupled to the body 110. The body 110 is configured to support an operator, multiple passengers, and / orcargo. The body 110 is also sufficiently buoyant to support the watercraft 100a on the water (e.g., when the watercraft 100a is stationary or traveling at sufficiently slow speeds). The main foil subassembly 130 includes a primary hydrofoil 132 and the propulsion subassembly 150 includes a secondary hydrofoil 158 and a thruster 152 (e.g., with electric motor(s)). As shown in FIGS. 2B and 2C, the primary hydrofoil 132 and the secondary hydrofoil 158 are fully submersible (FS) hydrofoils.

[0088] When deployed, the thruster 152 provides propulsion to propel the watercraft 100a along the water. The primary hydrofoil 132 and the secondary hydrofoil 158, in turn, generate a lift force applied to the watercraft 100a. The lift force may elevate the body 110 of the watercraft 100a such that the body 110 is partially or, in some instances, entirely above the water, thus reducing hydrodynamic drag. This, in turn, allows the watercraft 100a to travel at relatively higher nautical speeds while using relatively less energy, thus increasing the travel range of the watercraft 100a.

[0089] The body of the watercrafts disclosed herein may generally have one or more hulls to support the watercraft on the water. In some implementations, it may be preferable for the body to have two or more hulls to provide greater stability when the watercraft is traveling at slow speeds or is stationary in the water (see, for example, displacement and park modes described below). For example, FIGS. 1A and 1C show the body 110 of the watercraft 100a may have two hulls 112A and 112B. The hulls 112A and 112B may be parallel and of a similar or same size and / or shape. The hulls 112A and 112B may further be coupled together by a bridge deck 116 resulting in a body 110 similar to a catamaran.

[0090] The bridge deck 116 may include a cockpit 118 (also referred to herein as a “passenger area 118”) with a control station for an operator to operate the watercraft 100a. The cockpit 118 may further provide space to accommodate one or more passengers and / or to store cargo. In some implementations, the bridge deck 116 may include a separate cabin for one or more passengers and / or storage of cargo and / or the hulls 112A and / or 112B may provide space to store cargo. The watercraft 100a, as depicted in FIGS. 1A-5C, is shown supporting up to five people (e.g., the operator and four passengers) with seats and seatbelts for each person. In some examples, the watercrafts disclosed herein may support from one person to six people or, alternatively, a total occupant mass up to about 1500 lb. In some implementations, the watercrafts disclosed herein may carry up to about 300 lb of cargo evenly distributed around the body such that the cargo does not induce any undesirable roll or pitch of the watercraft.

[0091] The bridge deck 116 may further include a canopy 120 to enclose the cockpit 118 while allowing the operator and / or the passengers to view the surrounding environment. In some implementations, the canopy 120 may be retractable or foldable (hence, the canopy 120 is also referred to herein as a “convertible canopy 120”). For example, the canopy 120 may be mounted to a motorized sliding rail mechanism that moves the canopy 120 horizontally along the length of the body 110. When retracting the canopy 120, the canopy 120 may translate towards the stem of the watercraft 100a. When the canopy 120 is retracted, the cockpit 118 may provide an open deck where the operator and / or the passengers are exposed to and / or have direct access to the surrounding environment to facilitate open-air travel. It should be appreciated that the canopy 120 is a non-limiting example and that other types of windows and / or canopies may be implemented in the watercrafts disclosed herein. For example, the watercraft 100a may include one or more windshields (see, for example, the windshield 119 of the watercraft 100b in FIGS. 7A-7C).

[0092] The body of the watercrafts disclosed herein may be shaped to reduce aerodynamic drag, e.g., when the body is elevated above the water (e.g., see ground effect (WISE / WIGE) and elevation modes described below). A reduction in aerodynamic drag may, in turn, further increase the top speed of the watercraft, allow for further reductions in the energy used to propel the watercraft at a desired speed, and / or increase the travel range of the watercraft. For example, the watercraft may have a drag coefficient less than or equal to about 0.1, including all values and sub-ranges in between. In some implementations, the watercraft may have a drag coefficient less than or equal to about 0.05, including all values and sub-ranges in between.

[0093] In some implementations, the body may further be shaped to generate aerodynamic lift as the watercraft moves across the water. For example, FIG. IB shows the bridge deck 116 of the watercraft 100a may be shaped like an airfoil. When watercraft 100a moves along the water such that air flows above the bridge deck 116 and below the bridge deck 116 between the hulls 112A and 112B, a lift force may be generated to elevate the watercraft 100a. The lift generated by the bridge deck 116 may supplement the lift generated by the primary hydrofoil 132 and the secondary hydrofoil 158. This, in turn, may allow the primary hydrofoil 132 and the secondary hydrofoil 158 to operate with shallower angles of attack, further reducing hydrodynamic drag during operation.

[0094] In some implementations, the close proximity of the bottom side of the bridge deck 116 (also referred to herein as an “undersurface”) to the water may give rise to ground effect (also referred to in the art as a “wing-in-ground-effecf ’ WIGE or “wing-in-surface-effecf ’ WISE).In ground effect, the watercraft 100a experiences less lift-induced drag due to reduction in downwash as air flows across the bridge deck 116. Ground effect may only become appreciable when the operating height of the bridge deck 116 above the water, defined as the distance between the bottom side of the bridge deck 116 and the waterline 101, is less than or equal to about half the “wingspan” of the watercraft 100a (e.g., the width of the bottom side of the bridge deck 116). Herein, the lift force generated by the body 110 and / or the airfoils 114A and 114B in WIGE mode is referred to as a “ground-effect lift.”

[0095] The foregoing aerodynamic effects may be further augmented by the inclusion of one or more airfoils that extend from the body of the watercraft. For example, the watercraft 100a includes a pair of airfoils 114A and 114B that may extend from the sides of the body 110 over the water to produce additional aerodynamic lift (see, for example, FIGS. 2A-2C). In some implementations, the airfoils 114A and 114B may be retractable and extendable with respect to the body 110. For example, the airfoils 114A and 114B may be mounted to a rotary mechanism that pivots the airfoils 114A and 114B outwards for deployment and inwards for storage within the bridge deck 116, e.g., below the cockpit 118 as shown in FIGS. IB and 2B. The bridge deck 116 may further include openings through which the airfoils 114A and 114B may move inwards and outwards. When retracted, the leading edges of the airfoils 114A and 114B may conform to the shape of the bridge deck 116 to maintain a low drag coefficient (see, for example, FIG. 1A). In some implementations, the airfoils 114A and 114B may only be extended when traveling across water and retracted to reduce the space occupied by the watercraft 100a when docked. It should be appreciated that, in some implementations, the watercrafts disclosed herein may include airfoils that are fixed in position on the sides of the body.

[0096] The airfoils 114A and 114B may also generate aerodynamic lift as the watercraft 100a moves across the water, further supplementing the lift generated by the body 110, the primary hydrofoil 132, and the secondary hydrofoil 158. In some implementations, the airfoils 114A and 114B may be positioned on the watercraft 100a such that, when the airfoils 114A and 114B are extended and the watercraft 100a is moving along water, the airfoils 114A and 114B are located proximate to the water to provide ground effect, as described above. Here, the airfoils 114A and 114B increase the overall wingspan, S, of the watercraft 100a, thus increasing the operating height range of the watercraft 100a where ground effect is appreciable. Here, the operating height, H, may be defined as the average distance between the bottom side of the airfoils 114A and 114B and the bridge deck 116 and the waterline 101.

[0097] In some implementations, an increase in the operating height range and the ease of adjusting the operating height during operation of the watercraft 100a may be facilitated in part, by constructing the watercraft 100a and, in particular, the body 110 to be lightweight. A body 110 with a relatively lower weight requires less energy to adjust its operating height compared to a body 110 with a relatively higher weight. Moreover, a body 110 with a relatively lower weight may achieve a greater operating height for a given lift force compared to a body 110 with a relatively higher weight.

[0098] Reductions to the weight of the body 110 may be accomplished in several ways. For example, the body 110 or, more generally, the watercraft 100a may be formed of various lightweight materials including, but not limited to, carbon fiber composites, fiberglass, and aluminum. In some implementations, the watercraft 100a may be constructed using multiple materials. For example, metals may be used where the watercraft 100a is more vulnerable to damage during operation (e.g., the hulls 112A and 112B) and composites may be used for the remainder of the watercraft 100a.(0099] The main foil subassembly 130, as described above, includes the primary hydrofoil 132, which provides the primary source of the lift force to elevate the watercraft 100a above the water during operation. As shown in FIGS. 1A-1C, the main foil subassembly 130 may be located towards the stem of the watercraft 100a behind the propulsion subassembly 150. It should be appreciated that the arrangement of the main foil subassembly 130 and the propulsion subassembly 150 is a non-limiting example. In some implementations, the respective locations of the main foil subassembly 130 and the propulsion subassembly 150 may be switched such that the propulsion subassembly 150 is located towards the stern of the watercraft 100a behind the main foil subassembly 130, which is located towards the bow of the watercraft 100a. The main foil subassembly 130 includes adjustable vertical stmts 134A and 134B to support and position the primary hydrofoil 132 at a desired depth below the water. The stmts 134A and 134B may each be movably coupled to the body 110 so that the vertical position of the main foil subassembly 130 and, in particular, the primary hydrofoil 132 may be readily changed during operation with respect to the body 110.

[0100] Specifically, the adjustable vertical stmts 134A and 134B may each extend through openings formed on the hulls 112A and 112B, respectively, and be supported by respective adjustment mechanisms (e.g., hydraulic lifts, complementary linear or rotating gears, linear actuators engaging keyed rails, etc.). The adjustment mechanisms may controllably adjust the vertical position of the main foil subassembly 130 by moving the stmts 134A and 134B throughthe openings with respect to the body 110. The adjustment mechanisms may further securely hold the struts 134A and 134B at a desired vertical position when no adjustments are being made. In some implementations, the adjustment mechanisms may allow the struts 134A and 134B to rotate with respect to the body 110 about a horizontal axis extending from the starboard to the port of the watercraft 100a. This, in turn, may allow the pitch of the body 110 to change during operation while the main foil subassembly 130 remains vertically aligned (see, for example, FIG. 2B).|010.1] Additionally, the hulls 112A and 112B or, more generally, the body 110 may provide battery module compartment(s) to contain respective storage sections 136, e.g., when the struts 134A and 134B are vertically raised such that the storage sections 136 are disposed above the waterline 101. For example, the openings on the hulls 112A and 112B may be shaped to allow the storage sections 136 to pass through as shown in FIG. IB.

[0102] The primary hydrofoil 132 may include adjustable flaps and / or rudders to change the angle of attack of the primary hydrofoil 132 and, thus, the amount of lift generated by the primary hydrofoil 132 when deployed in the water. The operation of the flaps and / or rudders of the primary hydrofoil 132 may be controlled by a controller 104 on the watercraft 100a, which is discussed in further detail below. For example, a steeper angle of attack may be used to generate a relatively larger lift force to elevate the body 110 above the water as the watercraft 100a is accelerating. As the speed of the watercraft 100a increases, the angle of attack of the primary hydrofoil 132 may be reduced to reduce hydrodynamic drag while maintaining the desired elevation of the body 110 above the water.

[0103] In some implementations, the main foil subassembly 130 may also support one or more battery modules 140 to supply electric power to the thruster 152. In some implementations, the battery modules 140 may provide the watercraft 100a with a range of operation of at least 50 nautical miles. For example, FIG. IB shows the struts 134A and 134B may each include a storage section 136 to contain multiple battery modules 140. The storage section 136 may be disposed near the primary hydrofoil 132 towards the bottom portion of the struts 134A and 134B. When the main foil subassembly 130 is lowered into the water, e.g., to deploy the primary hydrofoil 132, the battery modules 140 may thus be positioned towards the bottommost portions of the watercraft 100a. The battery modules 140 may generally constitute a substantial portion of the overall weight of the watercraft 100a. By positioning the battery modules 140 in this manner, the center of gravity of the watercraft 100a may be appreciably lowered during operation. A lower center of gravity may generally provide greater stability tothe watercraft 100a. For example, the battery modules 140 may function as a ballast to counteract lateral forces applied to the watercraft 100a during operation, thus reducing the risk of the watercraft 100a capsizing in response to the lateral forces. The lateral forces may include, for example, forces due to cross winds and / or a wave striking the watercraft 100a (e.g., during rough sea conditions).[0104| FIGS. 6A-6C show several magnified views of the storage section 136 in the strut 134A and the battery modules 140 contained therein. As shown, the storage section 136 may include a cavity 138 to contain therein multiple battery modules 140. Each battery module 140 may include one or more battery cells 142. As shown, the storage section 136 may be integrally formed in each of the struts 134A and 134B. During operation, the storage section 136 may be disposed in air, partially disposed in water and partially disposed in air, or fully submerged in the water. Thus, the storage section 136 may be shaped to be hydrodynamically and / or aerodynamically streamlined. Said another way, the storage section 136 may be shaped such that water and / or air may readily flow around the storage section 136 without generating an appreciable amount of hydrodynamic drag and / or aerodynamic drag, respectively. In one nonlimiting example, the top of the storage section 136 may have a relatively larger cross section (e.g., a portion that has a relatively longer length) that gradually reduces in size towards the bottom of the storage section 136 where the strut 134A joins the primary hydrofoil 132, as shown in FIGS. 6A-6C.[0105| The battery cells 142 may be rechargeable. This may be facilitated, in part, by the watercraft 100a including a charge port (not shown). The charge port may adhere to various industry standards for electrical systems in marine vehicles. For example, the charge port and, more generally, the electrical systems of the watercraft 100a (e.g., the battery modules 140, the electric motors in the thruster 152) may meet the International Electrotechnical Commission (IEC) 60092 series of standards for electrical installations in ships, which is incorporated herein by reference. In some implementations, the battery modules 140 may include battery cells 142 that may be charged from about 0% capacity to about 80% capacity within about 40 minutes.

[0106] The propulsion subassembly 150 includes the secondary hydrofoil 158, which provides a secondary source of the lift force to elevate the watercraft 100a above the water during operation, and the thruster 152 to provide propulsion for the watercraft 100a. As shown in FIGS. 1A-1C, the propulsion subassembly 150 may be located towards the bow of the watercraft 100a in front of the main foil subassembly 130. The propulsion subassembly 150 may include a strut 156 to support and position the secondary hydrofoil 158 and the thruster152 at a desired depth below the water. The strut 156 may be movably coupled to the body 110 so that the vertical position of the propulsion subassembly 150 and, in particular, the secondary hydrofoil 158 and the thruster 152 may be readily changed during operation with respect to the body 110.

[0107] FIG. IB shows the strut 156 may extend through an opening formed along the cockpit 118 of the body 110 and supported by an adjustment mechanism (not shown). Similar to the adjustment mechanisms for the struts 134A and 134B, the adjustment mechanism for the strut 156 may controllably adjust the vertical position of the propulsion subassembly 130 by moving the strut 156 through the opening with respect to the body 110. The adjustment mechanisms may further securely hold the strut 156 at a desired vertical position when no adjustments are being made. In some implementations, the adjustment mechanism may allow the strut 156 to rotate with respect to the body 110 about a horizontal axis extending from the starboard to the port of the watercraft 100a. This, in turn, may allow the pitch of the body 110 to change during operation while the propulsion subassembly 150 remains vertically aligned (see, for example, FIG. 2B).

[0108] The vertical position of the strut 156 may be adjusted independently with respect to the struts 134A and 134B. Accordingly, during operation, the thruster 152 and / or the secondary hydrofoil 158 may be located at the same vertical position as the primary hydrofoil 132, above the primary hydrofoil 132, or below the primary hydrofoil 132. These relative vertical positions include configurations where the primary hydrofoil 132, the secondary hydrofoil 158, and the thruster 152 are submerged in water (i.e., below the waterline 101).

[0109] The secondary hydrofoil 158 may include adjustable flaps and / or rudders to change the angle of attack of the secondary hydrofoil 158 and, thus, the amount of lift generated by the secondary hydrofoil 158 when deployed in the water. The operation of the flaps and / or rudders on the secondary hydrofoil 158 may be controlled by a controller 104 on the watercraft 100a, which is discussed in further detail below. Similar to the primary hydrofoil 132, the secondary hydrofoil 158 may be configured to have a relatively larger angle of attack to elevate the body 110 above the water (e.g., when the watercraft 100a is accelerating) and a relatively smaller angle of attack to maintain a desired elevation and reduce hydrodynamic drag when the watercraft 100a is traveling at a desired speed.

[0110] The secondary hydrofoil 158 may also adjust the pitch of the body 110. For example, the secondary hydrofoil 158 may be configured to adjust the pitch of the body 110 such thatthe bow of the body 110 is higher than the stern of the body 110 (see, for example, ground effect mode in FIG. 2B). This orientation may allow the airfoils 114A and 114B and / or the body 110 to generate more aerodynamic lift. In some implementations, the pitch may be changed from about -10 degrees to about 10 degrees, including all values and sub-ranges in between. The secondary hydrofoil 158 may also provide a way to compensate for external forces acting on the watercraft 100a that may influence and / or otherwise change the orientation of the watercraft 100a (e.g., the pitch, roll, and / or yaw of the watercraft 100a). For example, if the watercraft 100a travels across relatively rough sea conditions, the choppiness of the water may cause the watercraft 100a to pitch up and down in an undesirable manner. The external forces causing the pitch to change may be compensated, in part, by the secondary hydrofoil 158 actively adjusting its angle of attack based on measured sea conditions (see, for example, the sensor 102 in FIG. IB).|0111] The thruster 152 may include one or more electric motors (not shown) that are configured to drive a propeller 154. The electric motor(s) may receive electrical power from the battery modules 140. In some implementations, the electric motor may be a direct-drive motor and / or submergible in water. As shown in FIGS. 1 A-5C, the watercraft 100a may include a single thruster 152. In some implementations, the thruster 152 may be steerable. Thus, the direction of the thrust generated by the thruster 152 and, by extension, the direction of travel of the watercraft 100a, may be controllable during operation. For example, the thruster 152 may be rotatably coupled to the strut 156 via a motorized rotary mechanism. The rotary mechanism may controllably rotate the thruster 152 about a rotation axis and hold the thruster 152 at a desired orientation. In some implementations, the rotation axis may be a vertical axis.

[0112] It should be appreciated that the thruster 152 is a non-limiting example. In other example implementations contemplated herein, the watercraft 100a may include two or more thrusters. The thruster(s) may further be offset horizontally with respect to a centerline 103 of the body 110 and configured to rotate in opposite directions. In other words, the multiple thrusters may provide counter-rotating propellers 154. The thruster(s) may further be independently controllable. Thus, the watercraft 100a may be steerable by adjusting the thrust generated by each thruster such that thruster(s) disposed on one side of the watercraft 100a generate more thrust than the thruster(s) disposed on the opposing side of the watercraft 100a. It should also be appreciated that if the primary hydrofoil 132 and the secondary hydrofoil 158 are deployed in the water, the watercraft 100a may change its direction of travel by rolling to one side as the watercraft 100a moves along the water. This motion causes the lift forcegenerated by the primary hydrofoil 132 and the secondary hydrofoil 158 to tilt in direction to one side, thus causing the watercraft 100a to turn towards that same direction in a manner similar to an airplane making a turn.

[0113] The watercraft 100a may include a controller 104 to manage the operation of the watercraft 100a. The controller 104 may include at least one processor and memory. The memory may be configured to store software, which when executed by the processor(s), facilitates operation of the watercraft 100a.[01.14] In some implementations, the controller 104 may be operatively coupled to various sensors onboard the watercraft 100a. FIG. IB shows the watercraft 100a may include a sensor 102 to monitor sea conditions, which is coupled to the controller 104. The sensor 102 may include, but is not limited to, a Light Detection and Ranging (LiDAR) system to measure the topology of the water surface in front of the watercraft 100a. In other implementations, the controller 104 may be communicatively coupled to one or more additional sensors that may or may not be on-board the watercraft. For example, the controller may be in communication with: one or more acoustic sensors; one or more nearby buoy systems equipped with one or more sensors to provide real-time data on wave height, period, direction, and frequency (NDBC network; wave rider / Datawell buoys); one or more remote sensing satellites (e.g. using SAR sensing techniques); one or more nearby aircraft equipped with radar altimeters; and / or one or more coastal radar systems.

[0115] During operation, the sensor(s) 102 (and / or other sensors with which the controller is communicatively coupled) may acquire data on the topology of the water surface and this data may be transmitted to the controller 104 to generate a model of the water surface. The controller 104, in turn, may use this model to (A) adjust the various control surfaces of the watercraft 100a, e.g., the control surfaces of the primary hydrofoil 132, the secondary hydrofoil 158, and / or the airfoils 114A and 114B and / or (B) adjust the vertical positions of the main foil subassembly 130 and / or the propulsion subassembly 150 to compensate for variable sea conditions based on the topology of the water surface. In some implementations, these adjustments may occur in time intervals that are less than 1 second.

[0116] The controller 104 may appreciably improve the ease of operating the watercraft 100a by alleviating the need for the operator to adjust various components manually. In some implementations, the operator may operate the watercraft 100a in a manner similar to a conventional powerboat. For example, the operator may provide a steering input and / or athrottle position to indicate a desired direction of travel and a desired speed, respectively. The controller 104, in turn, may adjust the various control surfaces and / or subassemblies noted above based on the operator’s inputs and data on the operating environment of the watercraft 100a.[0117| For example, the controller 104 may automatically adjust one or more of the control surfaces and / or subassemblies noted above such that the body 110 maintains a relatively constant elevation and / or a desired pitch. This, in turn, may provide a relatively smoother ride for the operator and / or the passengers and / or maintain the watercraft 100a in ground effect mode. In another example, the controller 104 may adjust the vertical positions of the main foil subassembly 130 and / or the propulsion subassembly 150 to transition the watercraft 100a between different modes of operation according to different sea conditions.

[0118] Some examples of the watercrafts disclosed herein may be classified as a small craft according to the National Oceanic and Atmospheric Administration (NOAA). In some examples, the watercrafts disclosed herein may have a range of at least 100 miles while maintaining an average nautical speed of 25 knots. The watercrafts disclosed herein, when fully loaded with passengers and / or cargo, may have a total weight less than or equal to about 3000 lb. The watercrafts disclosed herein may be configured to operate in marine environments where waves may have a height up to about 2 meter. The watercrafts disclosed herein may operate in an environment with winds from any direction up to about 20 knots.

[0119] 2. Example Modes of Operation

[0120] The watercraft 100a, as described above, may support several modes of operation to accommodate, for example, different sea conditions (“sea states”) and / or different operating environments. As noted earlier, “sea state” typically refers to the overall condition of the sea surface in terms of wave height, wave frequency, and wave patterns caused by local windgenerated waves at a certain location and moment in time. Sea state includes both local windgenerated waves and swell when considering the overall condition of the sea surface at a certain location and moment in time. Two examples of graded scales used to describe sea state include the Beaufort Wind Scale and the Douglas Sea Scale. Generally speaking, the Beaufort Wind Scale tends to be more commonly used by trained mariners and oceanographers to describe sea state as compared to the Douglas Sea Scale.|0121| In various examples disclosed herein, an electric watercraft is configured to operate in five different modes as follows:

[0122] 1) a wing-in-surface-effect (WISE) foiling mode (also referred to herein as wing-in- ground effect or WIGE, or simply “ground effect mode”) in the presence of sufficiently calm or smooth sea states (e.g., waves of less than 2 feet or 0.5 meters, wind speed of less than or equal to 6 knots; Beaufort number 0 - 2);

[0123] 2) an elevated foiling mode in the presence of slight or moderate sea states (e.g., waves of from about 2 feet to 6 feet, or 0.5 meters to 2 meters; wind speed of from about 7 knots to 16 knots; Beaufort number 3 - 4);

[0124] 3) a displacement mode in the presence of rough sea states (e.g., waves of from about 6 feet to 9 feet, or 2 meters to 3 meters; wind speed of from 17 knots to 21 knots; Beaufort number 5) and when the watercraft is departing from and arriving at a land interface;

[0125] 4) a stability (emergency) mode in the presence of very rough, high or very high sea states (e.g., waves greater than 9 feet or 3 meters; wind speed above 21 knots; Beaufort number 6 or higher); and

[0126] 5) a park mode.

[0127] In one aspect, the different modes of operation may be distinguished, in part, by different vertical positions of the main foil subassembly 130 and the propulsion subassembly 150. Further, the watercraft 100a may transition between the different modes of operation, in part, by adjusting the vertical positions of the main foil subassembly 130 and the propulsion subassembly 150 relative to the body 110.

[0128] Displacement mode may be used when the watercraft 100a is navigating shallow waters, such as during arrival to or departure from land (e.g., a port terminal). In some implementations, displacement mode may also be used when the watercraft 100a is traveling at relatively slow speeds through rough sea conditions. In displacement mode, the watercraft 100a may be supported on the water primarily by the buoyancy of the body 110. FIGS. 1 A-1C show the main foil subassembly 130 is vertically raised such that the primary hydrofoil 132 is above a waterline 101. The battery modules 140 are also disposed above the waterline 101. The propulsion subassembly 150 may also be raised to bring the secondary hydrofoil 158 and the thruster 152 closer to the body. However, the thruster 152 may remain submerged in the water to provide propulsion. In displacement mode, the watercraft 100a may travel at nautical speeds up to about 12 knots.

[0129] WISE / WIGE (ground effect) mode may be used, for example, when the watercraft 100a is traveling at relatively high speeds in relatively calm sea conditions. In ground effect mode,FIGS. 2A-2C show the main foil subassembly 130 and the propulsion subassembly 150 may be lowered with respect to the body 110 so that both the primary hydrofoil 132 and the secondary hydrofoil 158 are submerged in the water. As shown, the distances 131 and 151 may increase compared to displacement mode. Thus, as the watercraft 100a moves along the water, the primary hydrofoil 132 and the secondary hydrofoil 158 may both generate lift to elevate the body 110. Additionally, the airfoils 114A and 114B may be extended so that the body 110 and / or the airfoils 114A and 114B together generate aerodynamic lift. In some implementations, the body 110 may be elevated such that the bottommost portion of the body 110 is about 2 meters above the waterline 101.

[0130] The main foil subassembly 130 and the propulsion subassembly 150 may be vertically positioned such that, when the watercraft 100a is traveling at a desired speed, the body 110 and / or the airfoils 114A and 114B are located near the waterline 101. In particular, WISE / WIGE (reduction of lift induced drag) becomes noticeable when the height is about half the wingspan of the watercraft 100a and increases in effect as the height decreases. Under these conditions, the body 110 and / or the airfoils 114A and 114B may operate with ground effect where aerodynamic lift is generated with less lift-induced drag. In other words, the body 110 and / or the airfoils 114A and 114B may generate aerodynamic lift more efficiently.

[0131] In some implementations, the primary hydrofoil 132 and the secondary hydrofoil 158 may operate at lower angles of attack to reduce hydrodynamic drag in this mode. Although this means the primary hydrofoil 132 and the secondary hydrofoil 158 generate less hydrodynamic lift, the reduction in lift may be compensated by the aerodynamic lift generated by the body 110 and / or the airfoils 114A and 114B. Accordingly, the reduction in drag may allow the watercraft 100a to travel more efficiently, e.g., at higher speeds with a longer range of travel. In ground effect mode, the watercraft 100a may travel at nautical speeds up to about 30 knots.

[0132] In some implementations, the body 110 may be pitched with the bow higher than the stem so that the body 110 and / or the airfoils 114A and 114B are oriented to generate more aerodynamic lift as shown in FIG. 2B. For example, the body 110 may be pitched upwards such that the centerline 103 of the body 110, which extends from the bow to the stern of the watercraft 100a, is oriented about 3 degrees from a horizontal plane. The main foil subassembly 130 and the propulsion subassembly 150, however, may remain vertical or substantially vertical as the body 110’s pitch is changed.[01331 Elevation mode may be used, for example, when the watercraft 100a is traveling at relatively high speeds in relatively moderate conditions where ground effect is difficult to maintain. In elevation mode, FIGS. 3A-3C show the main foil subassembly 130 and the propulsion subassembly 150 may be lowered even further with respect to the body 110 compared to ground effect mode, i.e., the distances 131 and 151 are greater. The airfoils 114A and 114B may be retracted in elevation mode. The primary hydrofoil 132 and the secondary hydrofoil 158 may be configured to have a relatively larger angle of attack than ground effect mode to provide sufficient lift. With this arrangement, this mode may elevate the body 110 higher above the waterline 101 compared to ground effect mode (e.g., greater than 2 meters) such that the body 110 passes over most waves. In this manner, any drag caused by the watercraft 100a passing through the waves may be appreciably reduced or, in some instances, mitigated. In elevation mode, the watercraft 100a may travel at nautical speeds up to about 12 knots.[01341 Emergency mode may be used, for example, when the watercraft 100a is traveling in sufficiently rough sea conditions where there is a risk of the watercraft 100a capsizing. In emergency mode, FIGS. 4A-4C show the main foil subassembly 130 and the propulsion subassembly 150 may be positioned at the same vertical position relative to the body 110 as in elevation mode. The airfoils 114A and 114B may also be retracted in emergency mode. However, the watercraft 100a may be traveling at relatively slower speeds such that the body 110 is partially submerged in the water and the watercraft 100a is largely supported by the buoyancy of the body 110. In other words, emergency mode is differentiated from elevation mode based on the speed of the watercraft 100a. At slower speeds, the hydrofoils do not generate as much lift, thus the watercraft 100a is lowered into the water in a similar manner as displacement mode. In this mode, the main foil subassembly 130 and the propulsion subassembly 150 may provide a ballast to counteract any external forces exerted upon the watercraft 100a. This is facilitated, in part, by the main foil subassembly 130 and the propulsion subassembly 150 lowering the center of gravity of the watercraft 100a.[0135| Park mode may be used, for example, to park and / or store the watercraft 100a at a dock. In park mode, FIGS. 5A-5C show the main foil subassembly 130 and the propulsion subassembly 150 may be raised such that the primary hydrofoil 132, the secondary hydrofoil 158, and the thruster 152 is raised above the waterline 101. Accordingly, the watercraft 100a may be supported on the water by the buoyancy of the body 110. The airfoils 114A and 114B may be retracted in park mode so that the watercraft 100a occupies less space.[01361 3. An Example Watercraft with Battery Modules Mounted to Struts

[0137] FIGS. 7A-10C show another example watercraft 100b with struts 134A and 134B that include torpedo-shaped storage sections 137, respectively, that contain one or more battery modules 140. The watercraft 100b may share several of the same features as the watercraft 100a and may operate in a similar manner to the watercraft 100a. For brevity, repeated discussions of these features and / or operations may not be provided below.

[0138] The storage sections 137 may be dimensioned to contain a sufficient number of battery modules 140 so that the watercraft 100b has a range of operation of at least 50 nautical miles. As shown, the storage sections 137 may be positioned along the struts 134A and 134B such that the storage sections 137 are generally located above the waterline 101 during operation to reduce hydrodynamic drag. However, it should be appreciated the storage sections 137 may be submersible in water.

[0139] Additionally, the hulls 112A and 112B or, more generally, the body 110 may provide battery module compartment(s) to contain respective storage sections 137 or at least allow the storage sections 137 to move vertically upward alongside the bridge deck 116, e.g., when the struts 134A and 134B are vertically raised such that the storage sections 137 are disposed above the waterline 101. For example, FIGS. 7A-7C show the storage sections 137 disposed alongside the bridge deck 116 in when the watercraft 100b is in displacement mode.

[0140] In some implementations, the storage sections 137 may repeatedly pass through waves when the watercraft 100b is operating, for example, in rough sea conditions. Each time the storage section 137 passes through a wave, a force may be applied to the storage section 137, causing the orientation and / or the speed of the watercraft 100b to suddenly change, thus compromising ride comfort. To compensate for these forces, the controller 104 of the watercraft 100b may actively adjust the thrust generated by the thruster 152. For example, the controller 104 may command the thruster 152 to provide more thrust when the storage section 137 is passing through water to compensate for increases in hydrodynamic drag and / or provide less thrust when the storage section 137 is passing through air. In some implementations, the struts 134A and 134B may be lowered such that the storage sections 137 are fully submerged in water. This may occur, for example, in appreciably rough sea conditions.

[0141] The watercraft 100b may further include a bridge deck 116 with a windshield 119. As described above, the windshield 119 may provide the operator and / or the passengers with a way to view the surrounding environment, albeit with a more constrained field of viewcompared to the canopy 120 in the watercraft 100a. In another example, FIGS. 11 A-l 1C show another example watercraft 100c with struts 134A and 134B that include torpedo-shaped storage sections 137 and a canopy 120. The watercraft 100c may share several of the same features as the watercrafts 100a and 100b and may operate in a similar manner to the watercrafts 100a and / or 100b. For brevity, repeated discussions of these features and / or operations may not be provided below.

[0142] 4. Conclusion

[0143] All parameters, dimensions, materials, and configurations described herein are meant to be example and the actual parameters, dimensions, materials, and / or configurations will depend upon the specific application or applications for which the inventive teachings is / are used. It is to be understood that the foregoing embodiments are presented primarily by way of example and that, within the scope of the appended claims and equivalents thereto, inventive embodiments may be practiced otherwise than as specifically described and claimed. Inventive embodiments of the present disclosure are directed to each individual feature, system, article, material, kit, and / or method described herein.[01441 In addition, any combination of two or more such features, systems, articles, materials, kits, and / or methods, if such features, systems, articles, materials, kits, and / or methods are not mutually inconsistent, is included within the inventive scope of the present disclosure. Other substitutions, modifications, changes, and omissions may be made in the design, operating conditions and arrangement of respective elements of the example implementations without departing from the scope of the present disclosure. The use of a numerical range does not preclude equivalents that fall outside the range that fulfill the same function, in the same way, to produce the same result.

[0145] Also, various inventive concepts may be embodied as one or more methods, of which an example has been provided. The acts performed as part of the method may be ordered in any suitable way. Accordingly, embodiments may be constructed in which acts are performed in an order different than illustrated, which may include performing some acts simultaneously, even though shown as sequential acts in illustrative embodiments.

[0146] All publications, patent applications, patents, and other references mentioned herein are incorporated by reference in their entirety.|0147| All definitions, as defined and used herein, should be understood to control over dictionary definitions, definitions in documents incorporated by reference, and / or ordinary meanings of the defined terms.10148] The indefinite articles “a” and “an,” as used herein in the specification and in the claims, unless clearly indicated to the contrary, should be understood to mean “at least one.”

[0149] The phrase “and / or,” as used herein in the specification and in the claims, should be understood to mean “either or both” of the elements so conjoined, i.e., elements that are conjunctively present in some cases and disjunctively present in other cases. Multiple elements listed with “and / or” should be construed in the same fashion, i.e., “one or more” of the elements so conjoined. Other elements may optionally be present other than the elements specifically identified by the “and / or” clause, whether related or unrelated to those elements specifically identified. Thus, as a non-limiting example, a reference to “A and / or B”, when used in conjunction with open-ended language such as “comprising” can refer, in one embodiment, to A only (optionally including elements other than B); in another embodiment, to B only (optionally including elements other than A); in yet another embodiment, to both A and B (optionally including other elements); etc.

[0150] As used herein in the specification and in the claims, “or” should be understood to have the same meaning as “and / or” as defined above. For example, when separating items in a list, “or” or “and / or” shall be interpreted as being inclusive, i.e., the inclusion of at least one, but also including more than one, of a number or list of elements, and, optionally, additional unlisted items. Only terms clearly indicated to the contrary, such as “only one of’ or “exactly one of,” or, when used in the claims, “consisting of,” will refer to the inclusion of exactly one element of a number or list of elements. In general, the term “or” as used herein shall only be interpreted as indicating exclusive alternatives (i.e., “one or the other but not both”) when preceded by terms of exclusivity, such as “either,” “one of,” “only one of,” or “exactly one of.” “Consisting essentially of,” when used in the claims, shall have its ordinary meaning as used in the field of patent law.

[0151] As used herein in the specification and in the claims, the phrase “at least one,” in reference to a list of one or more elements, should be understood to mean at least one element selected from any one or more of the elements in the list of elements, but not necessarily including at least one of each and every element specifically listed within the list of elements and not excluding any combinations of elements in the list of elements. This definition alsoallows that elements may optionally be present other than the elements specifically identified within the list of elements to which the phrase “at least one” refers, whether related or unrelated to those elements specifically identified. Thus, as a non-limiting example, “at least one of A and B” (or, equivalently, “at least one of A or B,” or, equivalently “at least one of A and / or B”) can refer, in one embodiment, to at least one, optionally including more than one, A, with no B present (and optionally including elements other than B); in another embodiment, to at least one, optionally including more than one, B, with no A present (and optionally including elements other than A); in yet another embodiment, to at least one, optionally including more than one, A, and at least one, optionally including more than one, B (and optionally including other elements); etc.

[0152] In the claims, as well as in the specification above, all transitional phrases such as “comprising,” “including,” “carrying,” “having,” “containing,” “involving,” “holding,” “composed of,” and the like are to be understood to be open-ended, i.e., to mean including but not limited to. Only the transitional phrases “consisting of’ and “consisting essentially of’ shall be closed or semi-closed transitional phrases, respectively, as set forth in the United States Patent Office Manual of Patent Examining Procedures, Section 2111.03.

Claims

CLAIMS1. A watercraft (100) comprising: a body (110) to carry multiple passengers; a main foil subassembly (130) comprising a primary fully submersible (FS) hydrofoil (132) to generate a lifting force as the primary FS hydrofoil moves through water; and a propulsion subassembly (150) comprising at least one electric motor (116) to directly drive at least one propeller (154) to generate a propulsive force for the watercraft, wherein at least one of the main foil subassembly or the propulsion subassembly includes at least one adjustable vertical strut (134A, 134B, 156) coupled to the body to transmit at least one of the lifting force or the propulsive force to the body and to adjust at least one distance (131, 151) between the body and at least one of the primary FS hydrofoil or the at least one electric motor such that the at least one of the primary FS hydrofoil or the at least one electric motor is controllable over at least two different nominal operating depths in the water below the body during operation of the watercraft.

2. The watercraft of claim 1, wherein: the main foil subassembly further comprises a first adjustable vertical strut (134A) and a second adjustable vertical strut (134B) coupled to the primary FS hydrofoil and to the body to transmit the lifting force to the body and to adjust a first distance (131) between the primary FS hydrofoil and the body.

3. The watercraft of claim 2, wherein the main foil subassembly is disposed closer to the stem than to the bow of the body.

4. The watercraft of claim 2, wherein: the propulsion subassembly further comprises at least a third adjustable vertical strut (156) coupled to the at least one electric motor and to the body to transmit the propulsive force to the body and to adjust a second distance (151) between the at least one electric motor and the body such that the at least one electric motor and the at least one propeller are disposed under the waterline (101) during operation of the watercraft.

5. The watercraft of claim 4, wherein: the propulsion subassembly is a rotatable propulsion subassembly to facilitate steering of the watercraft.

6. The watercraft of claim 4, wherein: the main foil subassembly is disposed closer to the stern than to the bow of the body; and the propulsion subassembly is disposed closer to the bow than to the stern of the body.

7. The watercraft of claim 4, wherein: the at least one electric motor of the propulsion subassembly includes a first electric motor (152) and a second electric motor (152) to facilitate steering of the watercraft.

8. The watercraft of claim 7, wherein the propulsion subassembly comprises: the third adjustable vertical strut coupled to the first electric motor and to the body; and a fourth adjustable vertical strut coupled to the second electric motor.

9. The watercraft of claim 7, wherein: the main foil subassembly is disposed closer to the bow than to the stern of the body; and the propulsion subassembly is disposed closer to the stern than to the bow of the body.

10. The watercraft of claim 4, wherein the propulsion subassembly further comprises: a secondary FS hydrofoil (158) coupled to at least the third adjustable vertical strut.

11. The watercraft of claim 1, wherein the at least one electric motor generates all of the propulsive force for the watercraft.

12. The watercraft of claim 1, wherein the body further comprises: a controllable airfoil (114A, 114B) that controllably extends from the body and controllably retracts into the body.

13. The watercraft of claim 1, wherein:the body is a catamaran body comprising a first hull (112A), a second hull (112B) and a bridge deck (116) coupled to the first hull and the second hull.

14. The watercraft of claim 13, wherein the catamaran body is configured and arranged to facilitate a ground-effect lift in a wing-in-ground-effect (WIGE) foiling mode.

15. The watercraft of claim 13, wherein the bridge deck of the catamaran body comprises: a passenger area (118) for the multiple passengers; and a convertible canopy (120) covering at least a portion of the passenger area, wherein the convertible canopy is retractable and / or foldable to facilitate at least partially open-air travel for the multiple passengers during operation of the watercraft.

16. The watercraft of claim 1, further comprising: at least one battery module (140) mounted to and / or disposed in at least a portion of the main foil subassembly, the at least one battery module comprising at least one rechargeable battery (142) to provide power for generation of the propulsive force by the at least one electric motor.

17. The watercraft of claim 1, wherein at least one vertical strut includes at least one cavity (138), and wherein the watercraft further comprises: at least one battery module (140) contained in the at least one cavity of the at least one vertical strut, the at least one battery module comprising at least one rechargeable battery (142) to provide power for generation of the propulsive force by the at least one electric motor.

18. The watercraft of claim 1, further comprising: at least one sensor (102) to measure a sea state of the water through which the watercraft is operating; and a controller (104), communicatively coupled to the at least one sensor, to operate the watercraft, based on the measured sea state of the water through which the watercraft is operating, in one of: a wing-in-ground-effect (WIGE) foiling mode in the presence of calm or smooth sea states; an elevated foiling mode in the presence of slight or moderate sea states;a displacement mode in the presence of rough sea states and when the watercraft is departing from and arriving at a land interface; and an emergency mode in the presence of very rough, high or very high sea states.

19. The watercraft of claim 18, wherein: the body has a shape to significantly reduce air resistance as the body moves through air in the elevated foiling mode; and the body has an underbody shape to significantly increase a ground-effect lift in the WIGE foiling mode.

20. The watercraft of claim 18, wherein: the watercraft further comprises at least one battery module (140) mounted to at least a portion of the main foil subassembly, the at least one battery module comprising at least one rechargeable battery (142) to provide power for generation of the propulsive force by the at least one electric motor; and an undersurface of the body includes at least one battery module compartment to contain the at least one battery module in the displacement mode.

21. The watercraft of claim 18, wherein the at least one electric motor and the at least one propeller are disposed under the water during all operating modes of the watercraft.

22. A method of operating a watercraft (100), the watercraft comprising: a body (110) to carry multiple passengers; a main foil subassembly (130) comprising a primary fully submersible (FS) hydrofoil (132) to generate a lifting force as the primary FS hydrofoil moves through water; and a propulsion subassembly (150) comprising at least one electric motor (152) to directly drive at least one propeller (154) to generate a propulsive force for the watercraft, wherein at least one of the main foil subassembly or the propulsion subassembly includes at least one adjustable vertical strut (134A, 134B, 156) coupled to the body to transmit at least one of the lifting force or the propulsive force to the body, the method comprising:adjusting at least one distance (131, 151) between the body and at least one of the primary FS hydrofoil or the at least one electric motor via the at least one adjustable vertical strut.

23. A watercraft (100) comprising:A) a body (110) to carry multiple passengers;B) a main foil subassembly (130) comprising: a primary fully submersible (FS) hydrofoil (132) to generate a lifting force as the primary FS hydrofoil moves through water; and a first adjustable vertical strut (134A) and a second adjustable vertical strut (134B) coupled to the primary FS hydrofoil and to the body to transmit the lifting force to the body and to adjust a first distance (131) between the primary FS hydrofoil and the body; andC) a propulsion subassembly (150) comprising: at least one electric motor (152) to directly drive at least one propeller (154) to generate all of the propulsive force for the watercraft; and a third adjustable vertical strut (156) coupled to the at least one electric motor and to the body to transmit the propulsive force to the body and to adjust a second distance (151) between the at least one electric motor and the body such that the at least one electric motor and the at least one propeller are disposed under the waterline (101) during operation of the watercraft.

24. A multi-mode electric watercraft (100) to adapt to varying sea states, the multi-mode electric watercraft capable of operating in a wing-in-ground-effect (WIGE) foiling mode and comprising:A) a catamaran body (110) to carry multiple passengers, the catamaran body configured and arranged to facilitate a ground-effect lift in the WIGE foiling mode and comprising a first hull (112A), a second hull (112B) and a bridge deck (116) coupled to the first hull and the second hull;B) a main foil subassembly (130) disposed closer to the stem than to the bow of the catamaran body to provide support for a significant portion of the weight of the catamaran body and the passengers, the main foil subassembly comprising: a primary fully submersible (FS) hydrofoil (132) to generate a lifting force as the primary FS hydrofoil moves through water; anda first adjustable rear vertical strut (134A) and a second adjustable rear vertical strut (134B) coupled to the primary FS hydrofoil and to the catamaran body to transmit the lifting force to the catamaran body and to adjust a first distance (131) between the primary FS hydrofoil and the catamaran body; andC) a propulsion subassembly (150) disposed closer to the bow than to the stern of the catamaran body and comprising: at least one electric motor (152) to directly drive at least one propeller (154) to generate all of the propulsive force for the watercraft; and an adjustable front vertical strut (156) coupled to the at least one electric motor and to the catamaran body to transmit the propulsive force to the catamaran body and to adjust a second distance (151) between the at least one electric motor and the catamaran body such that the at least one electric motor and the at least one propeller are disposed under the waterline (101) during operation of the watercraft.

25. An electric watercraft (100) comprising:A) a body (110) to carry multiple passengers;B) a main foil subassembly (130) comprising: a primary fully submersible (FS) hydrofoil (132) to generate a lifting force as the primary FS hydrofoil moves through water; and a first adjustable vertical strut (134A) and a second adjustable vertical strut (134B) coupled to the primary FS hydrofoil and to the body to transmit the lifting force to the body and to adjust a first distance (131) between the primary FS hydrofoil and the body; andC) a propulsion subassembly (150) comprising: at least one electric motor (152) to directly drive at least one propeller (154) to generate a propulsive force for the watercraft; and a third adjustable vertical strut (156) coupled to the at least one electric motor and to the body to transmit the propulsive force to the body and to adjust a second distance (151) between the at least one electric motor and the body, wherein: at least one of the first vertical strut, the second vertical strut and the third vertical strut includes at least one cavity (138) containing at least one battery module (140), the at least one battery module comprising at least one rechargeable battery (142) to provide power for generation of the propulsive force by the at least one electric motor.

26. A multi-mode electric watercraft (100) to adapt to varying sea states, the multi-mode electric watercraft capable of operating in: 1) a wing-in-ground-effect (WIGE) foiling mode in the presence of calm or smooth sea states; 2) an elevated foiling mode in the presence of slight or moderate sea states; 3) a displacement mode in the presence of rough sea states and when the watercraft is departing from and arriving at a land interface; and 4) a stability (emergency) mode in the presence of very rough, high or very high sea states, the watercraft comprising:A) a catamaran body (110) to carry multiple passengers, the catamaran body configured and arranged to facilitate a ground-effect lift in the WIGE foiling mode and comprising a first hull (112A), a second hull (112B) and a bridge deck (116) coupled to the first hull and the second hull;B) a main foil subassembly (130) disposed closer to the stem than to the bow of the catamaran body to provide support for a significant portion of the weight of the body and the passengers, the main foil subassembly comprising: a primary fully submersible (FS) hydrofoil (132) to generate a lifting force as the primary FS hydrofoil moves through water; and a first adjustable rear vertical strut (134A) and a second adjustable rear vertical strut (134B) coupled to the primary FS hydrofoil and to the catamaran body to transmit the lifting force to the catamaran body and adjust a first distance between the primary FS hydrofoil and the catamaran body;C) a propulsion subassembly (150) disposed closer to the bow than to the stern of the catamaran body and comprising: at least one electric motor (152) to directly drive at least one propeller (154) to generate a propulsive force, the at least one electric motor and the at least one propeller disposed under the water during all operating modes of the watercraft; and a front adjustable vertical strut (156) coupled to the at least one electric motor and to the catamaran body to transmit the propulsive force to the catamaran body;D) at least one battery module (140) mounted to and / or disposed in at least a portion of the main foil subassembly, the at least one battery module comprising at least one rechargeable battery to provide power for generation of the propulsive force by the at least one electric motor;E) at least one sensor (102) to measure a sea state of the water through which the watercraft is operating; andF) a controller (104), communicatively coupled to the at least one sensor, to operate the watercraft in one of the WIGE foiling mode, the elevated foiling mode, the displacement mode or the stability (emergency) mode based on the measured sea state of the water through which the watercraft is operating.

27. The watercraft of claim 26, wherein_the bridge deck of the catamaran body comprises: a passenger area (118) for the multiple passengers; and a convertible canopy (120) covering at least a portion of the passenger area, wherein the convertible canopy is retractable and / or foldable to facilitate at least partially open-air travel for the multiple passengers during operation of the watercraft.

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