The present application relates to the maritime industry. More specifically, the present application relates to sailing vessels.
Sailing vessels have been around for hundreds if not thousands of years. They universally comprise a vessel that is propelled by the wind on the surface of water. The propelling force on a vessel is provided by a wind catching mechanism in the form of a sail, wing, rotating propeller, etc. This wind can propel the vessel downwind very simply by virtue of the drag of the wind catching mechanism. However, if it is desired to proceed in a direction at least partially into the wind, then the wind catching mechanism must have the hydrodynamic property of lift, which generates a force perpendicular to the direction of the apparent wind. This lift can be utilized to make the vessel go forward partially into the wind, however this lift also generates a sideways force on the vessel, as well as a rolling moment along a longitudinal axis of the vessel. If the vessel is not to simply slip sideways under the influence of the side force, then it must resist this force. This can be accomplished in a rudimentary manner by virtue of some advantageous shaping of the vessel itself. Alternately, and much more efficiently, this is done with the use of a keel, which is typically an appendage to the vessel, that has its own hydrodynamic property of lift and thus when the vessel is moving, will generate an equal and opposite side force to the wind, thus enabling the vessel to go upwind instead of slipping sideways.
As mentioned above, the wind also generates a rolling moment which attempts to roll the boat about its longitudinal axis from bow to stern. This is due to the fact that there is the aerodynamic lift force generated by the wind on the wind catching mechanism, and it is located above the water, so the force becomes a moment which must also be resisted, or the vessel will roll over and capsize. This roll resistance is accomplished in traditional sailing vessels by virtue of the fact that there is a center of gravity of the vessel which is displaced laterally from the center of buoyancy when the vessel rolls, and this displacement provides a counter rolling moment, known as a righting moment. Typically, this approach is manifested in a vessel which has a center of gravity lower in the water than its center of buoyancy, and therefore when it is rolled somewhat, the center of buoyancy moves laterally and then provides a restoring moment when coupled with the center of gravity. This can be seen in a myriad of forms of current sailing vessels. Alternately, in a multihull vessel, the righting moment is provided by virtue of the fact that the center of gravity of the vessel is raised above the water by the force of the wind, and therefore there is a restoring righting moment between the center of gravity and the center of buoyancy in the outboard hull.
There are several disadvantages of traditional sailing vessels. First, because vessels float on top of the water, a drag is induced on the vessel due to the hullform being driven through the water and thus creating waves on the surface (a wake).
Second, surface vessels experience instability as waves, swells and wind act upon their hulls.
Third, the shape of surface vessels must generally be chosen to minimize the wave-making drag described above. Typically, this results in vessels that are necessarily slender and somewhat cylindrical in its wetted sectional shape. It is inefficient to stray from this design.
Fourth, the side force generated by a keel always acts to increase the rolling moment caused by the lift effect of the wind on the wind catching mechanism, because the method of generating the side force necessarily lies below the vessel's hull. This sideforce generation below the water surface produces a couple with the sideforce being generated by the wind above the water and the magnitude of the couple is now increased to encompass distance between the center of effort of the wind sideforce and the center of effort of the keel's opposing side force, thus acting cumulatively on the rolling moment created by the wind.
It would be desirable, therefore, to design a new type of sailing vessel that overcomes the disadvantages noted above.
The embodiments described herein relate to a sailing vessel having a hull and a keel submerged under water, propelled by a wind-catching assembly above water. In one embodiment, the sailing vessel comprises a submersible hull assembly, a keel coupled to and extending upwards from the hull assembly, and a wind-catching assembly coupled to and extending upwards from the keel for propelling the hull assembly underwater.
In another embodiment, a wind-powered attachment for an under-water vessel is described, comprising a wind-catching assembly coupled to and extending upwards from the keel for propelling the hull assembly underwater, a keel coupled to and extending upwards from the hull assembly, and means for coupling the keel to the under-water vessel.
The features, advantages, and objects of the embodiments of the present invention will become more apparent from the detailed description as set forth below, when taken in conjunction with the drawings in which like referenced characters identify correspondingly throughout, and wherein:
The present application describes various embodiments of a submerged sailing vessel. Generally, a submerged sailing vessel comprises a hull assembly, a keel coupled to and extending upwards from hull assembly towards a water surface, and a wind-catching assembly coupled to the keel for propelling the submerged sailing vessel. Unlike traditional sailing vessels, the hull assembly and keel are submerged below a water surface as the vessel is propelled by the wind-catching assembly above the water surface.
With hull assembly 102 being completely submerged under water surface 108, several advantages are realized over traditional, surface sailing vessels. First, because SSV is fully submerged, drag is reduced due to the elimination of wave-making drag on the water surface 108, as in traditional surface sailing vessels. Second, vessel stability is increased because SSV 100 no longer floats on water surface 108, reducing or eliminating forces that act on SSV 100 such as wind, waves, and swells. Third, restrictions on the shape of hull assembly 102 are greatly reduced, because hull assembly 102 no longer cuts through water surface 108. This allows a wider variety of hull sizes and shapes, such as the one shown in
The size, shape, weight and/or displacement of hull assembly 102, keel 104 and wind-catching assembly 106 must be carefully chosen to enable SSV 100 to maintain, generally, neutral buoyancy, while also considering other factors such as side forces that act on all three components, as well as a rolling moment and restoring force.
In one embodiment, design of SSV 100 begins by defining certain hull assembly parameters, such as the intended size and shape requirements, weight, displacement requirements, equipment requirements, center of gravity, center of buoyancy, drag, etc. First, hull 102 is designed to be submersible, i.e., having an inside area protected from the water when hull 102 is completely submerged underwater during vessel travel and operation. Generally, one objective in defining the hull parameters is a hull assembly that is generally negatively buoyant after factoring in equipment, fuel, passengers, crew, food, water, etc. and is further dependent on such factors as total vehicle mass, drag, and performance requirements. More particularly, 100 hull assembly 102 is generally negatively buoyant after including the weight of wind-catching assembly 106. Hull assembly 102 may comprise one or more engines, navigation equipment, a propulsion system, a steering system, one or more buoyancy compensators, life-support systems, etc. One benefit of hull 102 being completely submerged during operation is that its shape or cross-section is not limited to typical cylindrical torpedo shapes, but can generally comprise a wide variety of other shapes, such as spherical, rectangular, or an irregular shape, as shown in
Once the hull assembly has been defined, the keel 104 and wind-catching assembly 106 can be defined. Keel 104 generally comprises a longitudinal, hydrodynamic in cross-section, to create lift in opposition to the side force created by the wind against wind-catching assembly 106. Aspects of the keel comprise a length (span), width, cross-section, chord, weight, and displacement. The length, width and cross-section of the keel will determine how much side force the keel will experience as SSV 100 is propelled through the water by the wind. The span (i.e., perpendicular length of the keel) largely determines a righting moment that resists a rolling moment caused by the wind as it acts upon wind-catching mechanism 106, both acting about a buoyancy, as shown in
In one embodiment, keel 104 is wider near the water surface than where it is coupled to hull assembly 102. This arrangement provides for most of the volume of keel 104 as far above the center of gravity of SSV 100 as possible, thus increasing the righting moment, and provides some reserve buoyancy to combat the effects of waves.
Buoyancy is another factor in designing keel 104. In one embodiment, keel 104 is sized and shaped to have positive buoyancy, enough to offset the negative buoyancy of hull assembly 102 and the weight of wind-catching assembly 106 so that a general neutral overall buoyancy of SSV 100 is achieved. Of course, material selection affects the buoyancy of keel 104, so that must be figured into the design as well. In some embodiments, buoyancy is less of a factor when hull assembly 102 comprises a buoyancy compensation system, as will be explained in greater detail below.
The keel is typically constructed of a strong, stiff material such as wood, metal, or one of a variety of composite materials. In one embodiment, the keel may be at least partially hollow to increase its buoyancy. In another embodiment, the keel is inflatable, made from a flexible material such as rubber, synthetic rubber or similar compounds that are durable yet inflatable. In this embodiment, hull assembly typically houses one or more pumps, motors, or storage tanks coupled to an inlet port of keel 104 in order to inflate and/or deflate keel 104. In yet another embodiment, the keel is hollow throughout the length of the keel and large enough to allow one or more conduits to pass, such as in embodiments where electrical or plumbing conduits are desired. In yet still another embodiment, the keel is sized and shaped to allow the ingress and egress of one or more passengers and/or vessel operators from the water's surface into hull assembly 102.
The length and width of keel 104, (i.e., a side surface area), has an effect on the righting moment; the greater the side surface area of keel 104 the greater the righting moment applied to SSV 100 when wind blows over/against wind-catching assembly 106. The length and width of keel 104 is calculated to account for this righting moment, which is affected by the area of wind-catching assembly 106 and the rolling moment that it creates, as well as the mass and area of hull assembly 102, which also acts to counter-act the rolling moment. It is often advantageous for keel 104 to be wider near the water surface than near hull assembly 102, because by doing so, a greater righting moment is created. Additionally, the thickness of keel 104 may be tapered along its length, becoming thicker at the top and more narrow near the bottom, near hull assembly 102, which also serves to counter the rolling moment.
Keel 104 may be coupled to hull assembly using well-known techniques such as welding, bolting, riveting, adhesive bonding, etc. In another embodiment, keel 104 is pivotally coupled to hull assembly 102 that may allow hull assembly 102 either pitch fore and aft, from side-to-side, or both, potentially reducing the effects of wind, waves, and swells on SSV 100 or, more particularly, hull assembly 102.
Typically, wind-catching assembly 106 comprises at least one mast, at least one sail or “wing” and other components, such as a boom, rigging, etc. typically found on most traditional sailboats. The sail is configured to generate a force vector in response to wind blowing across and/or against the sail. The mast extends upward from the keel and the sail's “foot” or lower edge is ideally very close to the water surface, in some embodiments, a matter of inches. However, in practice the foot may be located a foot or more above the water surface, in an attempt to keep the sail from becoming wet due to the varying nature of the water surface as wind, waves and swells act on SSV 100.
In one embodiment, the sail is rigid and constructed from a lightweight, substantially rigid material such as molded fiber composite material or aluminum alloy. In cross-section, the sail (sometimes referred to as a “wing” or “wingsail”) is preferably configured as an airfoil that generates propulsive force (analogous to upward “lift” of an aircraft wing, but in a generally horizontal direction) regardless of whether the angle of attack is to the right or left of the wind, suitable foil configurations being known to those skilled in the relevant art. In another embodiment, the sail is constructed from a lightweight, flexible material such as cloth, nylon, Dacron®, Spectra®, Dyneema®, mylar, carbon fiber, etc. In these embodiments, wind-catching assembly 106 may be partially or fully inflated by the flow and pressure of incident wind, i.e., when wind-catching assembly 106 is formed similar to a ram air hang glider or kite wing.
The mast may be hollow or solid and constructed from a substantially rigid material such as wood, fiber composites, fiberglass, etc. In one embodiment, the mast is constructed telescopically in sections, allowing the mast to be extended and retracted, typically by a combination of one or more actuators, motors, gears, pulleys, gas or water pressure, etc. In another embodiment, a retractable/extendable mast may be made from a flexible, inflatable material that, when erected, forms a substantially rigid spar capable of supporting one or more sails.
Design considerations of wind-catching assembly 106 comprise size, weight, power production, rolling moment, and side force in a variety of wind conditions, cost, and, in some embodiments, extendibility/retractability.
After the hull assembly, keel and wind-catching assembly have been defined, a total weight, total displacement and righting moment of SSV may be determined, using calculations well known in the art. As mentioned previously, a righting moment is created by virtue of the fact that there is a center of gravity of SSV 100 located well-below the water surface, and a center of buoyancy near the water surface. When SSV 100 rolls due to wind acting on wind-catching assembly 106, the center of gravity of SSV 100 gets displaced laterally from the center of buoyancy, and there is a restoring, righting moment created to counter-act the rolling moment. In addition, the rolling moment is reduced or eliminated because keel 104 is located above the hull assembly, i.e., above a center of gravity of SSV 100, and thus the side force produced by keel 104 to counteract the side force produced by the wind against wind-catching assembly 106 also acts to reduce or eliminate the rolling moment. This is a major advantage over traditional, surface sailing vessels, where the keel always adds to the rolling moment.
If these calculations, above, indicate that a change is needed in one or more of the hull assembly, keel or wind catching assembly, one or more of these components may be re-designed, and the total weight, displacement and righting moment re-calculated in an iterative process until these calculations are acceptable.
Next, a number of hydrostatic and flotation calculations are performed, as well-known in the art, to ensure that SSV 100 meets all of the design requirements, and that it will in fact float with hull assembly 102 completely submerged, keel 104 completely/mostly submerged and wind-catching assembly positioned above the surface of the water.
Next, one or more performance metrics may be calculated, for example, calculations to predict aerodynamic and hydrodynamic performance in actual use, equilibrium, etc. If the performance results are not acceptable to the designer, the hull assembly, keel and/or wind-catching assembly design specifications may be altered in an effort to achieve desired results.
The arrangement of the components of SSV 110 is especially useful when loading and unloading SSV 110. Generally, during loading and unloading, SSV 110 is raised upwards until the hulls 102 float on the water surface, as shown in
After loading or unloading, SSV 110 may be lowered below the water surface, again using buoyancy-compensation techniques, until just wind-catching assembly 106 is protruding from the water surface.
In one embodiment, wind-catching assembly 106 is coupled to keel 104 via a passive, automatic wing control mechanism 200, as shown in
Once installed, pivot assembly 302 is rotatable about an axis through the center of through-hole 306, while roller 314 engages tension bar 318, as will be described in more detail below. Extension 316 may be needed in order to position roller 314 in contact with tension bar 318 in some embodiments. However, in other embodiment, roller 314 may be coupled directly to arm 312 or be incorporated as a protrusion of arm 312. In one embodiment, roller 314 comprises a contoured surface, such a cylinder or sphere, to lower a coefficient of friction between roller 314 and tension bar 318. In another embodiment, roller 314 is rotatable about a longitudinal axis of extension 316, or rotatable with respect to arm 312 in embodiments where extension 316 is not used. This, again, reduces friction between roller 314 and tension bar 318.
Tension bar 318 comprises a relatively thin section of stiff yet flexible material, such as one or more strips of metal, bendable plastic, or some other material having a bending stiffness. Tension bar 318 acts to supply a restoring force against roller 314 as roller 314 rotates about hole 306, caused by wind blowing across wind-catching assembly 106. Bending stiffness is (he resistance of a member against bending deformation, and is a function of elastic modulus, an area moment of inertia of the tension bar cross-section about an axis of interest, length of the tension bar, and boundary condition. The thickness and material selection of tension bar 318 determines the bending stiffness of tension bar 318 and, thus, a magnitude of a restoring force against roller 314 as roller 314 attempts to travel along tension bar 318. In one embodiment, the rotational moment caused by tension bar 318 is relatively constant, no matter the position of roller 314 about hole 306. The bending of tension bar 318 around drum 320 describes a radius where tension bar 318 is wrapped around the drum, but the free end remains tangent to the drum. This tangent “tail” applies a restoring force to roller 314, and thus transmitted to the wing, acting to restore the wing to an optimum apparent wind angle.
Tension bar 318 may be replaced, in other embodiments, with some other mechanism that exerts a restoring force against arm 312. For example, a spiral torsion spring could be used to provide the restoring force, two coil springs could be used, two gas-filled struts, or some other mechanism(s) known in the art for providing a restoring force against arm 312.
Tension bar 318 may experience side forces as roller 314 rotates around hold 306. To combat these forces, tension bar 318 is typically held in place by a fastener 322, such as a screw, bolt, rivet, etc. as shown, and/or by curling ends 324 of tension bar 318 and utilizing stops 326 to cause each end 324 to “hook” a respective stop 326 when roller 314 is rotated about hole 306.
The lift rotates wing 500 clockwise about mast 308 until roller 314 comes in contact with tension bar 318, as shown in
Similarly, when the apparent wind is coming from the port bow, as shown in
Wing 500 may rotate between the positions shown in
The moment causes wing 500 to rotate about mast 308. Without automatic wing control mechanism 200, wing 500 would rotate until it is in direct alignment with the apparent wind. However, as wing 500 rotates around mast 308, roller 314 travels along tension bar 318, as shown in
In some embodiments, SSV 100 may comprise additional components and/or capabilities. For example,
Ballast 900 acts as mass to increase the righting moment. The further away from hull assembly 102, the greater ballast 900 acts to increase the righting moment. Ballast 900 may be configured in a streamlined cross-section to reduce drag, and be constructed of materials having a strong negative buoyancy, such as iron, lead or steel. In another embodiment, ballast 400 is largely hollow and coupled directly to hull assembly 102, typically underneath, and its buoyancy controlled by either introducing water or air into ballast 900, as commonly known in the submarine arts.
In related embodiment, as shown in
Returning to
The platform 1102 may also be designed to offset the mast 308 from a keel centerline 1104, i.e., by positioning a mast through-hole fore of a connection point between keel 104 and platform 1102. It is well known in the art of naval architecture and yacht design that in order for a vessel to sail reasonably well or at all, the sideforce generated by the keel, hull, and rudder combination counteracts the sideforce generated a wind-catching mechanism. In addition, the moment created by the aerodynamic sideforce (from by the wind catching mechanism) and the hydrodynamic sideforce (created by the keel/hull/rudder assembly) about the vertical axis of the vessel must balance. In other words, the fore and aft location of the center of pressure of the wind catching mechanism and the center of effort of the hydrodynamic portion of the vessel must align. In practice, this is accomplished by careful design of the physical positions and sizes of the various components, and in operation is trimmed by use and control of the rudder which, when rotated, provides a variable amount of sideforce at its location on the vessel that, in turn, adds or subtracts from the hydrodynamic side of the moment equation, thus creating the required sideforce and moment balance. In a practical and typical design, the center of effort of the wing is placed forward of the center of effort of the keel (which is the primary hydrodynamic sideforce-generating element). As described above, this leaves the rudder to generate the remainder of the sideforce and to balance the moment about the vertical axis and provide straight line motion in the desired direction.
As mentioned previously, in some embodiments, keel 104 and/or wind-catching assembly 106 may be configured to be inflatable. In these embodiments, keel 104 and wind-catching assembly 106 may be deflated using one or more pumps, gears, pulleys, etc. so that wind-catching assembly 106 lies flat on or under the water surface, for stealth purposes. Keel 104 and/or wind-catching assembly 106 may be re-inflated when desired, or keel 104 and/or wind-catching assembly 106 may be jettisoned, in an embodiment where keel 104 is detachably coupled to hull assembly 102 and/or wind-catching assembly 106 is detachably coupled to keep 104. In such embodiments, typically a release cable emanating from hull assembly 102 is used as a mechanism to detach either keel 104, wind-catching assembly 106, or both.
In any of the embodiments discussed above, SSV 100 may be as small as a specialized instrumentation vessel or as large as an underwater hotel. In one embodiment, hull assembly 102 is approximately 4 feet long, 4 inches wide and 4 inches tall, keel 104 is 3½ feet long, having a chordlength of approximately 6 inches near hull assembly 102, and 12 inches near wind-catching assembly 106, while wind-catching assembly 106 is approximately 3½ feet high and having a sail or wing that is 3½ feet by 14 inches chordlength. These values dictate the speed, rotational moments, weight, buoyance, and other performance characteristics of SSV 100, and they may be scaled to achieve larger or smaller sized SSVs, and/or vary one or more of the dimensions to meet certain, predefined performance criteria. In larger embodiments, i.e., for carrying passengers and/or a crew, keel 104 may be configured to be hollow and comprise steps, stairs, a ladder or other means to load and unload such passengers and/or crew to/from SSV 100.
In this embodiment, coupling means 1202 comprises a large “hose clamp”, i.e., a constricting ring structure whose diameter is adjustable via adjustment means 1204. Adjustment means 1204 may comprise a banded screw or a spring. In the case of a banded screw, adjustment means 1204 comprises a grooved band of metal with a screw and a catch. The end of the band slides through the catch, and the screw is turned to tighten the band and constrict the diameter. In other embodiments, coupling means 1202 comprises, simply, a band of metal, plastic, or other flexible or semi-flexible material, sized and shaped to conform to the surface of the existing, under-water vessel. The band typically comprises a joint, or discontinuity and fastening means located at each end of the discontinuity, for allowing the band to be placed around the perimeter of the existing under-water vessel, then clamping the band around the perimeter using the fastening means to fasten each end to one another.
In either of the embodiments shown in
While the foregoing disclosure shows illustrative embodiments of the invention, it should be noted that various changes and modifications could be made herein without departing from the scope of the embodiments as defined by the appended claims. Furthermore, although elements of the invention may be described or claimed in the singular, the plural is contemplated unless limitation to the singular is explicitly stated.
The present application is a divisional of U.S. patent application Ser. No. 17/533,583 filed on Nov. 23, 2021, which is a divisional of U.S. patent application Ser. No. 16/550,915 filed on Aug. 26, 2019, now U.S. Pat. No. 11,180,232, which is a divisional of U.S. patent application Ser. No. 16/014,860 filed on Jun. 21, 2018, now U.S. Pat. No. 10,399,652, which is a divisional of U.S. patent application Ser. No. 15/645,831 filed on Jul. 10, 2017, now U.S. Pat. No. 10,029,773, which claims priority to provisional application No. 62/500,368 filed on May 2, 2017, all of which are assigned to the assignee hereof and hereby expressly incorporated by reference herein.
Number | Name | Date | Kind |
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4981099 | Holder | Jan 1991 | A |
Number | Date | Country |
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2552046 | Mar 1985 | FR |
WO-2015038182 | Mar 2015 | WO |
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20230271687 A1 | Aug 2023 | US |
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62500368 | May 2017 | US |
Number | Date | Country | |
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Parent | 17533583 | Nov 2021 | US |
Child | 18312818 | US | |
Parent | 16550915 | Aug 2019 | US |
Child | 17533583 | US | |
Parent | 16014860 | Jun 2018 | US |
Child | 16550915 | US | |
Parent | 15645831 | Jul 2017 | US |
Child | 16014860 | US |