REVOLVING SAILING CATAMARAN WATERCRAFT

FIELD OF THE INVENTION

The present invention relates to the field of sailing catamaran watercrafts, and in particular on sailing catamarans on which most of the weight and the crew are always on the one hull, while the hulls can revolve horizontally around each other for proper positioning, according to coming wind, so that most of the weight is always on the windward side.

BACKGROUND OF THE INVENTION

Catamarans on which the main portion of the weight and the crew is steadily on the one hull, while the hulls revolve around each other horizontally for positioning according to tack, that is according to the side from which the wind is coming from each time, have not been disclosed in the prior art.

For the purpose of the present invention, catamarans are watercrafts with two independent hulls, said hulls are connected above the water level by cross beams, or a bridgedeck. Until now, the known sailing catamarans, had steadily positioned hulls, while sailing. There are several variations, such as catamarans with displacement hulls, on which the hulls displace water to pass through, as they move forward, thus creating significant wake. Or catamarans with planning hulls on which as the craft accelerates the hulls are getting lifted very near the water surface by hydrodynamic lifting force and come in planning condition like water skis, this condition reduces the underwater frontal surface and the wake that is being produced by the movement, thus allowing significantly higher speeds. Or catamarans with hydrofoils under the hulls on which the hulls practically take-off and fly above the sea level with the lift and the support of small hydrofoils which pass through the water like airplane wings, thus reducing further the underwater frontal surface and simultaneously reduce also the total underwater side surface thus reducing side skin friction caused by the viscosity of water at higher speeds, at the same time reducing to a minimum level the created wake.

Another categorization of sailing catamarans is that there are symmetric and asymmetric catamarans. On symmetric catamarans the hulls have same size and are symmetrically positioned abeam, with the sailing gear placed symmetrically between the hulls. The sailing gear can consist of single or multiple masts, sails, and necessary rigging, either in longitudinal tandem positioning, or abeam positioning. On these sailing catamarans the crew, and possibly other movable weights, are customarily being moved and positioned each time on the starboard or port hull depending on which is the windward hull, for better performance with the purpose of better counter balancing the leeward roll of the rigging by the wind effect on the sails.

On asymmetric catamarans the hulls are asymmetric, one bigger and one smaller, and on which customarily the windward hull carries most of the weight, the crew, and even a possible ballast weight. An asymmetric catamaran can either be made for starboard sailing tack, or for port sailing tack. That is, for right side wind, or left side wind.

A comparison between monohulls versus symmetric catamarans, and between symmetric catamarans versus asymmetric is considered useful for the understanding of the advantages of the present invention.

The main advantage of customary symmetric catamarans, in comparison to monohull watercrafts, is that the extended width of the catamaran’s beam, from the widely apart hulls, corrects better the lateral rolling movement and side inclination which are produced by the force of the wind on the sails. The balancing torque is produced by the buoyancy or hydrodynamic lift of the leeward hull and the weight of the windward hull. A subsequent advantage caused by the said reduced roll, in comparison to a monohull, is that the resulting less inclination has a positive effect on the more vertical position of the masts, consequently on the stable geometry and better shape of the sails, on the higher projected surface to the oncoming wind for better aerodynamics and lift. It also results in reduced“weather helm” effect, that is the reduction of the unwanted side steering caused by the lateral disposition of the sail from above the keel.

Monohulls in general, are more agile and more maneuverable; but symmetric catamarans are agile and maneuverable enough for what is necessary for sailing. Catamarans can sail on port and on starboard wind, and they can successfully tack or gybe, thus turn their heading thoroughly through head wind or downwind, in order to change tack. The maneuverability of the catamarans is enough to allow common everyday use and also racing use, according to standard international racing regulations.

A well noted disadvantage of the wide beam of catamarans is that in most harbors there is usually hardship finding berthing places wide enough for such wide watercrafts. Comparing the symmetric catamarans against the asymmetric, the disadvantages of the symmetric catamarans are that fixed weights are equally distributed among the two hulls, thus the correcting force of lateral roll, produced by the buoyancy or lift of the leeward hull and the weight of the windward hull, is not the maximum that could be produced if most of the fixed weight could be positioned always on the windward hull..

The advantage of asymmetric catamarans is that the lateral correction force by the asymmetric hulls, on which the windward hull carries constantly most of the watercraft’s total weight and the weight of the crew, is significantly greater. Thus, the balancing force for the correction of roll by the wind effect is greater. This greater balancing force allows reduced total weight and increased sailing area, thus allowing higher speeds.

The disadvantages of asymmetric catamarans, against symmetric, is that by having the heavier hull steadily positioned, in practice, these catamarans can have only starboard wind configuration, or only port wind configuration. So they have the great disadvantage of sailing only on one tack, therefore are able to sail toward one direction only. After a run, they need to be towed or put on a land trailer in order to return back for a new run. Apart than breaking or holding a speed record said disadvantage makes these watercrafts not truly useful in real every-day sailing, or for racing use, according to standard international racing regulations, where a watercraft has to sail in many directions.

Still a well noted disadvantage of the wide beam of asymmetric catamarans, like on all catamarans, is that in most harbors there is usually hardship finding berthing places wide enough for such wide watercrafts. Asymmetric racing catamarans are more commonly being raised from the water and kept on land trailers. This is unwanted for a watercraft that is intended to be used also for common every-day use.

It is an object of the present invention to address advantageously the above disadvantages and deficiencies of the prior art, by proposing a catamaran watercraft on which most of the fixed weight, the crew, and any added ballast, are always on the one hull, while the sailing gear is near, or on, the other hull, and the hulls revolve around each other for positioning as necessary each time.

It is an object of the present invention to combine the advantages of the monohulls and of the symmetric catamarans which are maneuverable for common or for racing use, with the advantages of asymmetric catamarans which are presently the fastest ever sailing watercrafts. A further object of the present invention is to allow easier berthing by changing width, as necessary each time, with the use of the same mechanism for revolving and moving the hulls.

These and further objects, features and advantages of the invention will be fully apparent by the following detailed description.

BRIEF DESCRIPTION OF THE FIGURES

The invention will be understood to those skilled in the art with reference to the accompanying figures, in which the invention is shown in an exemplary, non- limiting way.

Figures 1 (a) and 1 (b) show in perspective view the revolving asymmetric catamaran on port tack.

Figures 2(a) and 2(b) show in perspective view the revolving asymmetric catamaran on starboard tack.

Figures 3(a) and 3(b) show the hinges of cross beam on main hull. The main hinge for horizontal rotation, the horizontal hinge and the horizontal movement of cross beam.

Figure 4 show indicatively a single cross beam with the hinge for rotation of mast and the driving mechanism for rotation of mainsail.

Figure 5 show an indicative mast assembly with the mainsail the mainsail boom and the mast hinge.

Figures 6(a) and 6(b) show the mast and mast hinge, foresail boom and foresail boom hinge, ama and ama hinge.

Figure 7 show the assembly of foresail, foresail boom, the forsail boom hinge and the driving mechanism for rotation of foresail boom.

Figure 8 show indicatively the secondary hull, or ama with the tail fins or rudder and the hinge of ama.

Figure 9 show an indicative maneuver for a tack.

Figure 10 show an indicative maneuver for a gybe.

DETAILED DESCRIPTION

Referring now to the accompanying figures, exemplary embodiments of the sailing catamaran watercraft with revolving hulls will be described, so that its features and advantages will be better understood. The sailing catamaran watercraft of the invention, as shown on Fig 1 (a), 1 (b), 2(a) and 2(b), consists of a main hull (1) which most commonly, but not absolutely, carries the major portion of the weight and the crew. One secondary hull (2) which will be referred as AMA, most commonly but not absolutely, supports the sailing gear (14) to (20). A cross beam (3), or an assembly of cross beams, connect the two hulls (1), (2). The main hull hinge and its vertical axis (4) on main hull (1), supports the cross beam (3) while allowing the horizontal angular rotation of the cross beam. This hinge (4) can, but not necessarily, allow a horizontal linear movement (5) of the cross beam (3), to allow extension of the cross beam (3) for a wider distance between the hulls of the watercraft, or retraction for narrower configuration of the watercraft. The hinge (4) can, but not necessarily, incorporate also a horizontal hinge and axis (6) Fig 1 (a), to allow vertical angular rotation of the cross beam (3) and subsequently of the mast (14) and the whole sailing rigging. If a horizontal hinge (6) is added to the hinge (4) of the main hull (1) then main hinge operates as a universal joint. Thus cross beam (3) and the whole sailing rigging (7) to (20), with the ama (2) can also lift-off and freely be positioned in a way similar to kite surfing.

The main hinge (4) and relevant vertical axis on main hull (1) can turn around horizontally initially fully 360 degrees. Any side rigging, like shrouds (7) and any other lines for the support of the sailing gear can be attached, directly from the mast (14), onto the cross beam (3) Fig 1 (a). These shrouds (7), either single or multiple, connecting the mast (14) with the cross beam (3) are normally sufficient to support the rigging and withhold the effect of wind on the sails, because cross beam (3) is always revolved and positioned on or very near to the direction of the wind. On larger watercrafts and masts, where there might be need for greater fore/aft/side support, said shrouds (7) can be attached on side extensions of the cross beam (8). In case of vastly big sailing gear where there might be need for more support and more fore and rear supporting lines, movable runners can be utilized for the support of the rigging. These are lines, common in racing sailing, which can be released completely and alternatively, as necessary. So these runners could be released to allow passing of any gear or sail during maneuvering, and fastened as necessary prior to tightening sails for higher speed. In this way the revolving freedom of cross beam (3) and of mast (14) will be maintained.

Main hinge (4) and cross beam (3) can, but not necessarily, be free to revolve horizontally freely around main hinge vertical axis (4), according to the pulling of the cross beam (3) by the wind effect on the sails and the trimming of the sails, in a way similar to kite surfing. Such release, of main hinge (4) horizontal revolving, could be advisable in general, with the exception of close-hauled sailing, which is the heading near towards the wind. During close hauled-sailing the fastening of cross beam (3) may be more advisable in abeam positioning or better in more front positioning than abeam, to reach heading closer to the wind, while simultaneously reducing the weather helm effect. The fastening methods of main hinge (4), and of all hinges, and the fine regulation at any desired angle will be explained on the text to follow.

The mast hinge (10), fig. 4, and relevant vertical axis of the mast connect the mast (14) with the cross beam (3). Said hinge (10) and relevant vertical axis allow the angular rotation of the mast (14) around the vertical axis, independently of the cross beam (3). In this way the mast (14) and sailing gear can maintain a direction to the wind independent of the horizontal angle of the cross beam (3).

Mast hinge (10) may possibly provide also free vertical revolution of mast (14) around a horizontal hinge and axis, if such hinge is incorporated near the mast vertical hinge and axis. Thus allow the inclination of mast (14) and of sails to be regulated toward or away from the cross beam (3) and from the oncoming wind, according to the attitude of the mast and the sail, in a way similar to kite surfing.

In addition, ama (2) incorporates also an independent vertical hinge, or universal, or ball hinge (11), Fig. 5, Fig 6(a) & Fig. 6(b), connecting the ama (2) to the cross beam (3). For simplicity of this presentation, but not necessarily, the figures show the independent hinge (11) as being attached on a lower extension of the mast (14). An alternative configuration could be if the mast (14) was anywhere along the cross beam (3), independently of the position of the ama (2).

With the utilization of hinge (11), ama (2) is free to rotate and to maintain heading independently of the cross beam (3) or the mast (14). For streamlining with the flow of the water, ama (2) may carry fixed tail-fins (12) or rudder (13), Fig. 8, which keep the heading of ama (2) streamlined, that is parallel to main hull heading, or with temporary differentiations of heading during maneuvering. Alternatively the ama (2) can simply be of an omni-directional kind of ski, or stepped ski, which planes on water surface freely on any direction, or a hydrofoil which allows free heading, or any other means for this purpose.

All angular rotations and linear movements, namely hinge (4) between cross beam (3) and main hull (1), hinge (11) between cross beam (3) and ama (2), the linear movement (5), and the vertical hinge (6) near main hinge (4), and especially hinge (10) between cross beam (3) and mast (14), are not necessarily free. They are driven either manually with handles, cranks, pedals or ropes, or by electric motors, or hydraulic, or pneumatic mechanisms, or by spring mechanisms preloaded before each maneuver for quick maneuvering, or by other means of driving. The mechanism to transform said driving into said angular rotations or linear movements can be by direct gears (17), (20), Fig. 6(b), (9) Fig. 3(a), or belt with pulleys, or geared transmission chains, or for small watercrafts by direct manual turning and manual 5 locking in some position, or by any other means of transferring the driving power into angular rotation or movement. It is also possible to utilize clutches on certain drives, to engage or disengage the drives, thus to allow both controlled programmed movements and also free movements similar to kite surfing, as necessary each time.

The sails can be either of flexible materials as the sails found in common 10 sailing art, or of rigid materials with airfoil profiles as found in the modern high performance sails.

The mast (14) and sailing gear can turn around mast revolving axis (10), fully 360 degrees, or if there are obstructions the turning may be restricted to less than 360 degrees.

15 More specifically, in case there are shrouds (7) being employed only from the top of the mast to the other end of the cross beam (3) and if top of mainsail is just triangular, then the 360 degrees of unobstructed turning of the mast will be maintained at all times.

In case there are more lines, such as shrouds from the top of foresail (22) Fig. 20 1 (a) to the cross beam (3), or a boom-vang and pulleys (24) Fig. 5, from the boom of mainsail (15) to the lower end of the mast (14), or a rectangular top fathead mainsail

(23), then the rotation of mast (14) may be restricted to less than 360 degrees, as the mainsail boom (15) will not be able to pass above the cross beam (3) because of the said obstacles. In this case, as described herein, the turning of the mast (14) and

25 sailing gear, in relation to the cross beam (3), will be restricted just only regarding the passing of the mainsail boom (15) above the cross beam (3). All other rotation of mast is still maintained unobstructed. As will be presented below this is not a problem for the proper conduct of sailing.

Steady tack sailing, according to present invention exhibits great advantages, 30 as in all asymmetric catamarans, because the major portion of the weight is kept furthest away on the windward side, while the sails may be positioned near or above the leeward end of cross beam (3). This configuration allows highest counterbalancing torque to correct the lateral wind effect on the sails, thus allowing less total weight and greater sail areas in comparison with any vessel of compatible 35 size. This results in significantly higher velocities. Tacking, as shown on figure 9, is changing direction by turning the heading of the bow through a head wind (21). In this case, main hull (1) starts turning close towards and against the oncoming wind (21) by the use of its momentum, while the cross beam (3) is turned downwind to the stern. At the same time the sails are loosened and the mast (14) and mainsail boom (15) are turned to keep the sails loose on the wind. After turning through the wind (21), and approaching the new sailing direction, cross beam (3) is being brought abeam, on the new lee side, while sails (22), (23) Fig. 1 (a) are tightened and trimmed as necessary to increase speed. Said tacking maneuver is far easier than tacking any other catamaran, because the total width is greatly reduced, during the revolving of the cross beam (3). Furthermore the revolving of ama (2) can be used to tack even with the worse conditions like with zero momentum, zero watercraft speed, and zero wind speed, simply by revolving the ama (2) the other way around than intended for the main hull (1). Such maneuver is impossible for any other sailing vessel.

Gybing, as shown on figure 10, is the opposite of tacking. That is changing direction by turning the stern through the direction of the oncoming wind (21). In this case main hull (1) starts turning leeward, away from the wind (21), while cross beam (3) is preferably turned fully downwind towards the bow, to let the mast (14) and all rigging to move with the wind, for better easiness of the maneuver. Mast axis (10) and mainsail boom (15) are gradually completely loosen and turned around, away through the downwind side, as on a windsurfing power gybe. Then momentarily, the sails get slack just like on tacking, and finally upon passing of the watercraft onto the new side of wind, the cross beam (3) is being brought abeam on the new lee side, while sails are tightened as necessary to increase speed. Gybing as described herein exhibits remarkable easiness. It is a maneuver easier than tacking because the mast (14) and cross beam (3) are let to go downwind, and the mainsail boom (15) likewise is let to go downwind, and watercraft maintains momentum endlessly going downwind. The procedure is taking place without abrupt changes, unlike during an ordinary gybe, because the mainsail (23) turns progressively and simultaneously with the vessel, like a free flag. For these reasons said described maneuvers of gybing and tacking, are easier not only in comparison to a regular catamarans but also easier than conventional monohull sailing watercrafts.

The above options for tacking and gybing are preferable for easiness, but are indicative and not absolute. Thus, the cross beam (3) can be turned toward and against the wind, or the mast (14) and mainsail boom (15) can gybe as on conventional yachts, with the boom turning against the wind. Both described maneuvers, as the best options for tacking and gybing, do not need full 360 degrees of revolving freedom between mast (14) and cross beam (3), to be performed. Because, in both tacking and gybing, mainsail boom (15), mainsail (23), and boom-vang (24), pass away, externally from the cross beam (3) and the shrouds (7). Foresail boom (16) and foresail (22) pass above the cross beam (3) but there is no obstruction in doing so. In this way it is possible to utilize not only shrouds (7) from the top of mast (14), but also shrouds from the top of foresail (22) Fig. 1 (a), to the other end of the cross beam (3), or the use of boom-vang (24) Fig. 5, from main sail boom (15) to lower part of mast (14), or rectangular fathead mainsail top, without the need for removable runners, that is without the need for removable shrouds.

Unobstructed turning of mast (14) Fig. 1 (a), around mast axis (10), according to present invention, means tacking, gybing and trimming of mainsail boom (15) and foresail boom (16) as necessary for best performance and speed. Turning and trimming is effected by the said mechanical or manual mechanisms (17), (20), or combination of these. Sheet lines, can additionally be used, which are operated as movable runners. These are double sheet ropes, which are used to tighten the sails, which can be loosened or tightened alternatively according to obstructions’ positions

As shown of figures 9 and 10, during the exact moment of tacking or of gybing, that is during the momentary passing of heading or of stern through the direction of the wind, there is a momentary loss of lateral stability because at that moment, main hull (1) and ama (2) are tandemly and longitudinally positioned, in-line along the wind. Apart that this phenomenon is momentary, the rolling effect is not as significant as during normal sailing, because the sails at that moment are slack, like a free flag. In any case, to address a possible rolling instability during the momentary longitudinal positioning of the hulls, various different options, known in the prior state of the art, may be utilized such as a constant or movable keel on main hull with ballast, or the use of a main hull of a wider beam and planning configuration for rolling stability, or the use hydrofoils in V configuration semi-submerged for balancing, or fully submerged hydrofoils with controllable angle of attack for regulation of the altitude and the lateral and longitudinal inclination and attitude of main hull, or other means to increase stability known in the art, or combination of these. Or additionally, according to the present invention, simply use of high rotational velocity of cross beam (3) as it rotates horizontally around main axis (4) for achieving near tangential course of ama (2) as it turns around main axis (4), thus momentary near perpendicular course of main hull (1) and ama (2) at the moment of longitudinal positioning of the hulls.

During high speed sailing, ama (2) can take-off and fly above sea level, this can be achieved by the proper inclination of the mast (14) towards the cross beam (3). The actual flying altitude of the ama (2) above sea level can be arranged during initial design of mast hinge (10) by inclination of mast towards the cross beam (3), and can be further regulated during sailing by the shrouds (7) and proper regulating of any shroud and side lines, in conjunction with the flexibility of mast, or a possible added horizontal hinge at the base of the mast (14). The take-off of the ama (2) from the sea level is caused by the lift generated by the inclination of mast towards cross beam (3), because the direction of the cross beam shows approximately the mean direction of the apparent coming wind. The more inclination of the mast (14) toward the cross beam (3) and the main hull (1), will result in higher lift and higher altitude of flying, and vice-versa. This technique of keeping the ama (2) airborne reduces significantly water friction and increases safety in heavy seas, because ama (2) can be flying safely above the waves. The lift and flying altitude of the ama (2) above sea level is independent of the strength of the wind and depends only on the inclination of the mast (14) against the cross beam (3), thus against the wind, much like a kite. This results in safe sailing during heavy wind. Best results regarding speed achieved when ama (2) is maintained just above sea level, so drag by water is practically zero because there is no contact of the ama (2) with the water, apart from some spray, while sail exposes maximum projected area to the oncoming wind, and also while the pulling of the watercraft is as horizontal as possible. In heavy seas when the safety is the more important factor than speed, best results are achieved if ama (2) is kept flying at more safe and higher altitude, above the waves with proper increase of inclination of mast (14) towards the cross beam (3).

In case of heavy seas it might be necessary to use additional hydrofoils with deeper depth under the water surface, or additionally vertical or different extensions of the hydrofoils, or the use of keels to avoid take-off of the total watercraft in the form of a jump.

Said possible configuration of flying ama (2) and mast (14), is better than a kite surfing, because as said, the rotation of components can be fastened at a prescheduled optimum position for better close-hauled sailing or other courses, and also because the lift of ama (2) can be regulated and be kept to a minimum, very near the sea level, for higher speed and safety. The concept of the one hull flying above sea level can also be opposite, that is if the ama (2) is kept on the water, while the main hull (1) is kept and regulated airborne at some relatively small altitude above sea level, or above the waves. This case can better, but not exclusively, be regulated if the inclination of mast (14) is not toward the cross beam (3), but the opposite. In a way in which as wind force and roll increase, projected sail area and rolling torque will decrease, and so there will be stability of roll and of flying altitude of the main hull (1). The advantage of such concept is that ama (2) has smaller underwater frontal surface, and total drag, therefore theoretically the craft can go even faster. The disadvantage is that the rolling stability is not as inherent as in the concept of the flying ama, whereas the inclination of mast (14) toward the wind, inherently and automatically regulates flying altitude and roll independently of the wind strength. This is because as the altitude of the ama (2) is increasing, with hinge (6) as the rotating pole for this rise, the angle of attack or the sails are reduced and therefore further lift is reduced. Thus the configuration of a flying ama (2) is quite safer regarding a possible lateral capsize incident, because flying altitude and roll are stable and independent of wind speed and force.

On the presently described example of a revolving catamaran, the foresail (22) has a foresail boom (16) which rotates around hinge (18), independently of the mast (14), driven and fastened by a geared drive and a geared wheel (20) Fig. 6(b), while the mainsail boom (15) is steadily affixed and rotates together with the mast

(14) Fig.5, driven and fastened by a another geared drive and a similar geared wheel (17) Fig 6(b). But these configurations are indicative for a presentation of an operative example, and not the object of the claimed present invention. Opposite configuration, or other different configurations, could be presented as an operative watercraft, including fastening of the various parts of the rigging with sheet ropes attached on the ama (2) as most regular sailing watercrafts.

On the presently described example of a revolving catamaran, sheet ropes of foresail are held and regulated by side extensions (19) Fig.6(a) of the mainsail boom

(15). But this is indicative and not the object of the present claimed invention. These and any other sheet rope can be held either from the ama (2) or from elsewhere.

During mooring in marinas and ports, either with the bow or with the stern, the cross beam (3) and ama (2) can be revolved and been brought longitudinally along the main hull (1), or at any other angle. For example, the ama can be revolved away from the dock toward the anchor, or in between the dock and the main hull (1), as gangway. In this way the necessary dock space to accommodate the vessel’s width is as much as a monohull

The revolving catamaran watercraft, according to present invention, consists initially of one main hull (1) and one secondary hull (2) which revolve around each other, around two vertical axes, of main hinge (4) of hull (1) and of hinge (11) of ama (2). Each of the said hulls can consist of multiple subsidiary hulls, whereas each set of hulls revolve around the other set of hulls. In this case the presentation of the watercraft will be alike the one of a trimaran or of a craft with more than three hulls.

It should be noted that the description of the invention was made with reference to an exemplary non-limiting embodiment. Thus, any variation or modification as regards the shape, dimensions, construction and assembling materials, components employed, and variant techniques for realization of the claimed revolving concept, as long as not constituting a new inventive step and not contributing to the technical advance of the already known are considered as encompassed in the scope of the present invention.