WO2010098726A2

WO2010098726A2 - Keel and sailing vessel incorporating same

Info

Publication number: WO2010098726A2
Application number: PCT/SI2010/000006
Authority: WO
Inventors: Tomaž GROM
Original assignee: Individual
Current assignee: Individual
Priority date: 2009-02-25
Filing date: 2010-02-19
Publication date: 2010-09-02
Anticipated expiration: 2011-08-25
Also published as: WO2010098726A3

Abstract

Next to the rigid part of the keel (10) which is firmly attached to the hull (50) of the vessel (5), the keel (1) comprises a rotatable part (2) which consists of two with each other firmly connected V- shaped foils that point apart and are at least approximately at right angles to each other (21, 22), or two separate in the same longitudinal axis rotatable foils where the angle between them can be adjusted. The foils are around the geometrical axis (100) of the keel (1) rotatably connected to the rigid part of the keel (10), so that each of the foils (21, 22) can optionally be turned from the approximately vertical into approximately horizontal position or vice versa, or held in a certain chosen position. At the free end (210, 220) of each of the foils (21, 22) at least one hydrodynamically designed weight (211, 221) is proposed. On the one hand this type of keel (1) ensures the vessel (5) the necessary ballast for maintaining the vessel's stability and minimizes the vessel's (5) listing around its longitudinal axis (201), and on the other hand enables the vessel (5) to adapt the hydrostatic characteristics to the conditions at the anchorage and its hydrodynamic characteristics while sailing, which improves the efficiency of the sails and increases the speed. Moreover, this kind of keel (1) is solid enough to withstand the weight of the whole vessel (5), which enables the maneuvering of the stranded vessel and optionally also offers support to the vessel on a flat or inclined area ashore, or when sailing at sufficient sailing speeds even the planing of the vessel (5).

Description

Keel and Sailing Vessel Incorporating Same

Background Information of the Invention Subject Invention

The subject invention is a keel designed particularly for single hulled vessels which are mainly wind-powered. According to international patent classification within the scope of transporting this type of invention belongs to the field of equipment for ships or other waterborne vessels with further classification according to construction details to the field of keels, in particular to those that decrease vessel movements by redistributing the weight and by using stabilizing foils that act on ambient water.

Field of Application

Description of the Technical Problem

The concept of the invention is to design a keel for wind-powered vessels that on the one hand ensures the necessary ballast for maintaining the vessel's stability and minimizes the vessel's listing around the longitudinal axis and on the other hand enables the vessel to adapt the hydrostatic characteristics to the conditions at the anchorage and its hydrodynamic characteristics while sailing. This would help improve the efficiency of the sails and in favorable wind conditions reduce the hydrodynamic resistance (drag) of the hull of the vessel to such an extent that higher speeds of the vessel would be assured. At the same time this kind of keel would have to be solid enough to withstand the weight of the whole vessel and thus not only enable the maneuvering of the stranded vessel, but optionally also offer support to the vessel on a flat or inclined area ashore, or when sailing at sufficient sailing speeds even the planing of the vessel. The aim of the invention is to construct a vessel incorporating this keel.

A classical rigid keel filled with the appropriate ballast ensures the stability of the wind-powered vessel and the protection against excessive rotation around the longitudinal axis and thus minimizes the possibility of capsizing. When the wind force, which blows approximately horizontally and at least approximately transversely to the longitudinal axis of the vessel, reaches the sails and the mast, the vessel starts heeling (it leans aside), or in other words rotates around its longitudinal axis. The keel mass consequently deviates from the vertical to oblique position. Deviation creates a lever foil which with the weight of the keel creates torque. That is why the vessel tends to rotate around the longitudinal axis back to the starting point. With smaller deviation the lever foil is less noticeable and consequently also the torque is correspondingly smaller, which with approximate sine dependence of the inclination angle considerably increases only with bigger keel deviation from the vertical. Consequently the pitch around the longitudinal axis even in normal weather conditions is relatively big and thus particularly bigger vessels offer less comfort. Besides, such a rigid keel also has a relatively large draft and this prevents the vessel to enter the shallow water areas.

However, problems with the vessel's draft can be solved by using a retractable keel (centerboard), but this brings additional problems with the installation of the keel and with the layout of the vessel's interior. Also the problem of sealing between the keel and the hull needs to be considered because not only that a retractable keel takes up a lot of space, also the hull of the vessel is impaired at the most sensitive part. Further problems then appear with the moving of the keel. And what is more, the vessel's listing around the longitudinal axis remains unchanged.

Present Solutions to the Problem

The US Patent 4,044,703 proposes a keel made of two complementary shaped parts that form a classical keel together. The upper vertically downwards directed wing with the hydraulically suitable cross section in the horizontal perspective is toughened up and filled with the appropriate ballast on the lower, from the hull more distant part. Each part forms a half of the symmetrically divided classical keel on the central vertical surface that runs through the longitudinal axis. Both complementary parts are attached to the pivot which is positioned at the bottom of the vessel's hull where also a classical keel is normally positioned. Its rotation axis rotates in direction of the longitudinal axis of the vessel. This means that both parts of the keel can be rotated separately or together in both directions around the pivot axis. For this purpose a suitable flexible element, e.g. a rope or a strap, is attached to the end of each of the parts, more precisely to the part where ballast is positioned, and this enables to rotate each separate part around the pivot and thereby hoist it or drop it. That is how the part of the keel on the windward side of the vessel can be moved from the vertical into approximately horizontal position to change the center of gravity. This results in smaller mast inclination and also in smaller rotation around the vessel's longitudinal axis. At least theoretically, both parts of the keel can be moved likewise. It is also possible to move both parts of the keel from the vertical into oblique or approximately horizontal position. This considerably reduces the draft of the vessel. However, despite unquestionably good results regarding the possibilities of altering the center of gravity and the draft of the vessel, the proposed solution has some serious weaknesses. Firstly, the aforementioned flexible elements increase the drag; they can even vibrate, and consequently reduce the sailing speed. Secondly, they are constantly exposed to water and its negative impacts. Thirdly, both parts of the keel are relatively difficult to manage with, especially since both, the rope or the strap, can tolerate solely tensile, but not also compressive forces. This means that when for example both parts of the keel are intended to be turned into same direction they have to be preliminary linked up. This is for example achieved by using a locking mechanism which is positioned on both parts of the keel. Managing such a locking mechanism is again very demanding and unreliable, especially because the most of the construction is exposed to the effects of water and water organisms (calcination). Furthermore, both parts of the keel are constructed asymmetrically, which means that they create forces that take the vessel off course in certain positions. When both parts of the keel are pushed aside but still relatively close to each other, a circulation channel is created and this results in even greater drag.

The US Patent 5,152,238 proposes a similarly designed segmented winged keel. This keel is made up of a pair of L-shaped parts, where each of horizontally positioned legs of the L-shaped wings points into its own direction and each vertically positioned leg is connected to the sprocket or to the grooved shaft, which enables to turn the legs from the vertical into horizontal position or vice versa. When both parts of the keel are completely apart, the final legs are positioned directly at the hull which minimizes the draft of the vessel. What is more, this position enables a stable support for the vessel when ashore. Although one might think that while sailing the outer parts of the keel legs at higher speeds create dynamic buoyancy that lifts the vessel out of the water and consequently reduces the drag, the reality is completely different. On the contrary, such a keel is particularly troublesome in terms of relatively high dynamic buoyancy. While sailing, the center of gravity can be altered by turning the part of the keel on the windward side of the vessel so that the outer part of the leg is close to the hull. In such position a canal is created between the hull and both legs. This considerably changes the course of the surrounding water and increases the drag drastically. Apart from that, the transmission that runs the aforementioned sprockets is relatively complicated and installed in special housing that is isolated from the hull. Its interior is therefore in general exposed to the effects of water and water organisms. It is clear that such a transmission can not serve its purpose after a prolonged exposure to the water or that it requests a constant and intensive maintenance to ensure proper operation, which is at least during long-time cruise impossible to provide. Furthermore, the US Patent 5,967,076 proposes a vessel comprising of multi-layered keel made up of at least two parts positioned one after another regarding the longitudinal axis of the vessel. The first part forms a keel with the ballast that can be rotated around its longitudinal axis. Then there is at least one wing that can optionally be filled with the ballast and can again be rotated around its longitudinal axis. The simplest construction comprises a keel and a wing, which is located in front or after the keel, while the preferential construction comprises the keel and at least one wing positioned before and after it. Either mechanical or hydraulic propulsion device rotate the keel and the wings around its longitudinal axis. Such a set of a keel and wings enables to alter the draft and the center of gravity in relation to its longitudinal axis. The steering of such a set is not very simple, but can although be carried out in rational and reliable way. The problem that needs to be tackled is a complicated way of steering because of the inconvenient arrangement of the keel and wings that are positioned one after another along the longitudinal axis. When the wings and the keel are turned in either way the torque is created around the vertical axis, or at right angles to the longitudinal direction of the vessel, and consequently the vessel is carried off its intended course. Apart from that, the relatively complicated keel and wings set does not create dynamic buoyancy in vertical direction that would push the vessel out of the water and reduce dynamic resistance (drag) and consequently enable sailing at higher speeds.

The US Patent 6,453,836 Bl proposes a keel comprising a rigid vertical part to which a rotatable lower part is attached. The wing can be moved from the vertical to horizontal position or vice versa and at the same time rotated around its axis. For this purpose, an appropriately steered engine in the rigid part of the keel can be provided. When the wing is in approximately vertical position, the vessel's draft increases and consequently also the stability and the protection against excessive rotation around the longitudinal axis. If the wing is rotated around its axis, the course of the vessel can be altered as well. When the wing is in approximately horizontal position, the draft is smaller and at higher speeds the force on the wing is created, whose direction depends on the rotation of the wing. When rotating the horizontally positioned wing around its axis in either direction dynamic buoyancy that is opposite to the force of gravity is created. As a result, the vessel is pushed out of the water and to some extent the drag of the vessel is reduced. When rotating the horizontally positioned wing around its axis in the opposite direction the force is directed into the same direction as the force of gravity, but its initial point is positioned on a certain lever foil regarding the center of gravity of the vessel which means that this force creates a torque that is for example opposite to the torque of the wind force on the sails and thus reduces the listing of the vessel around its longitudinal axis. Considering the construction of the wing which is cantilevered and rotates around its axis, which is positioned at the end of the rigid part of the keel, the load in the area where the wing is cantilevered and operated from is already in normal sailing conditions relatively high. Apart from that, the rigid part of the keel is in any case rather long, which means that a vessel always has a relatively big draft. Furthermore, the way that the wing is fixed to the keel (cantilevered) neither provides support to the vessel if e.g. the vessel runs aground or if put on the solid surface ashore nor withstands such hydrodynamic forces that would enable the vessel to start planing at higher speeds.

Solution to the Problem

The subject invention is a keel of the sailing vessel that in general comprises a suitably rigid part fixed to the hull which has with regard to the streamlines flowing in the longitudinal direction between the bow and the stern of the vessel particularly hydrodynamic and symmetrically designed cross section. The aforementioned rigid part is positioned below the waterline and at least approximately below the center of gravity of the vessel, whose current direction is each time defined with the longitudinal axis of the vessel.

Next to the aforementioned rigid part the keel according to the invention also comprises a rotatable part that consists of two with each other firmly connected V-shaped foils that point apart and are at right angles to each other (Fig. 2, 3 and 18, variants A, B and C), or of two separate in the same longitudinal axis rotatable foils (Fig. 6 through 16 and 19, variant D) where the angle between the foils can be adjusted in the range of approximately 20° to 200°. Cross section of the foils is hydrodynamic and particularly symmetrically designed. Both foils are rotatably connected with the rigid part of the keel around the keel's geometrical axis, so that each foil is rotatable from the approximately vertical to approximately horizontal position or vice versa by suitable propulsion device and optionally also kept in a certain chosen position. For the free part of each aforementioned foil at least one firmly fixed and hydrodynamically designed weight is proposed. Furthermore, at the free end of the rigid part of the keel a case is proposed, through which in its longitudinal direction runs the geometrical axis of the keel, around which either separate or joined (depending on the variant) rotatable foils are positioned. In all the variants the movable part of the keel comprises foils, ballast weights and a rotatable bearing socket which serves as a connection between the movable and the fixed part of the keel. The case of the socket is in the free frontal part 121 of the fixed part of the keel preferably hemispherically shaped, while the opposite part 122 is in at least approximate conoidal shape. The aforementioned propulsion device which rotates the foils around the axis and/or holds the foils in a chosen position is positioned inside the case and/or socket. The propulsion device can be a hydraulic motor with the planetary reduction gear or some other appropriate mechanical or mechanical hydraulic propulsion device (Fig. 17). The keel's longitudinal axis, around which aforementioned rotatable foils are positioned, preferably runs obliquely under appropriate angle in relation to the longitudinal axis of the vessel, which is parallel with the ideal waterline and coincides or is parallel with the sailing direction of the wind-powered vessel, so that the axis of the keel towards the bow nears the waterline and towards the stern withdraws from the waterline. The inclination between the keel's axis and the axis of the vessel is in general between 0,5° and 5°, preferably between 1° and 3° and in particular at least 1.5° (Fig. 5 - α).

In the simpler variant of the invention (variant A) each foil can consist of at least one wing which is in each case positioned on the outer side, more precisely on the side that points away from the other foil(s) and is at least approximately perpendicular to the outer surface of the foil(s). In particular this variant proposes one wing for each of the foils that is, when viewed from the keel's axis towards the free end of each foil, positioned on at least one third between the axis that rotates the foils and the longitudinal axis of the each belonging weight positioned on the end of each foil.

In more demanding variants of the possible constructions of the keel according to the invention (variants B, C, D) each of both foils are constructed in the shape of the letter L, so that the articulated parts of the foils that at the end have appropriate weights point to different directions and are either perpendicular to each other or preferably at least approximately at an angle of 60° (Fig. 4 - δ) in relation to the longitudinal surface of the foil. Foils can either be articulated in an acute angle or circularly with an optional radius (no drawing).

At the same time, the articulated parts 230, 231 are also additionally rotated on the elementary surface of the keel's foils 213, 223, so that the front part of the joint nears the pivot axis, while the rear part does the contrary; it withdraws from the pivot axis. In general this angle is approximately between 0.5° and 7°, preferably between 1° and 5° and particularly at least approximately 3°. When the foil of the keel in variants B, C or D is in its vertical position, the angle α of the keel's pivot axis 100 in relation to the parallel with the waterline 201 and articulation angle β in relation to the pivot axis 100 are reckoned up, then the inclination angle of the articulated part of the keel 230 or 231 in relation to the parallel with the waterline 201 forms a common angle γ (Fig. 5), which represents the sum of the both aforementioned angles (γ = α + β ).

In another proposed construction of the keel according to the invention (variants C, D) each of the aforementioned foils in the area next to the socket and at the rear part, in relation to the streamlines that run in the longitudinal direction between the bow and the stern of the vessel, can be equipped with at least one movable flap. Each flap can either be rotated around the axis which runs in the longitudinal direction of each foil between the axis and each free end of the foil, preferably at an angle from 1° to 10° and preferably at an angle of 6° in the direction pointing aside the hull of the vessel, or can optionally be held in a certain chosen position by a chosen propulsion device. Preferably only the flap, which is momentarily in approximately horizontal position, is dipped down in relation to the waterline (200), while the flap of the vertically positioned foil is in neutral position, so that the frontal resistance (drag) of the foil (21 or 22) and the side drift of the vessel (5) are as small as possible. The preferable propulsion device for shifting the aforementioned flaps is a hydraulic cylinder.

Furthermore, the hydraulic motor with the planetary reduction gear or some other technically appropriate mechanical propulsion device for rotating the foils around the keel's axis is connected to the set of hydraulic cylinders for shifting the flaps which form together an appropriately steered mechanical hydraulic set (Fig. 17), where at least the propulsion device for foil shifting can optionally be automatically controlled on the basis of the each time separately chosen parameters, in particular periodically repeated listing of the vessel around its longitudinal axis because of the more or less turbulent water.

The subject invention is a wind-powered vessel comprising at least a hull with a mast, sails, a rudder and a keel which is fixed to the hull and positioned at least approximately below the center of gravity and constructed in accordance with one of the aforementioned claims. The vessel's hull is at an adequate distance from the keel to the bow equipped with at least one directional stabilizer (55) that controls the vessel in direction which is parallel with the longitudinal axis of the vessel so that it prevents the vessel to turn around the vertical axis of the vessel when planing. A directional stabilizer (55) is preferably firmly fixed to the hull of the vessel and positioned on the longitudinal axis of the vessel at the appropriate point between the keel and the bow which is still below the waterline, more precisely on the bottom of the vessel's hull (50) in the area which is closer to the bow (51). The directional stabilizer consists of preferably two fins that are in cross section hydrodynamically and symmetrically designed. The vertically positioned fin (55a) provides stability for the vessel movement around the vertical axis and support for the horizontal fin (55b), which is positioned in the middle of and symmetrically transversely and perpendicularly to the vertical fin 55a (Fig. 1). The horizontal fin 55b is in transversal direction parallel to the waterline and in longitudinal direction inclined in such a way that it nears the waterline 200 in direction towards the bow of the vessel and moves away from the waterline in direction towards the stern. The longitudinal inclination of the horizontally positioned fin 55b is in general between 1 ° and 9°, preferably between 3° and 6°, in particular at least approximately 5° (Fig.l - ω). The fin 55b ensures that in favorable wind conditions the vessel starts lifting up its bow towards the waterline 200. By doing this, the relative angle of incidence of the keel 100 in relation to the waterline 200 temporary increases, which results in larger hydrodynamic buoyant force on each of the approximately horizontally positioned foils of the keel (1) and enables the vessel to start sailing on the underwater wings. When the frontal horizontal directional stabilizer 55b reaches the waterline 200, its further lifting is disabled, while the keel together with the rest of the vessel's hull lifts to the height where the resultant of the hydrodynamic buoyant force on the keel is the same as the resultant of the weight of the vessel 5. The cross section of the horizontal fin 55b can be symmetrically, but preferably asymmetrically designed in order to additionally increase the dynamic buoyancy that lifts the vessel towards the water surface (200).

A full understanding of the invention can be gained from the following description of the preferred embodiments when read in conjunction with the accompanying drawings in which:

> Fig. 1 A perspective of the keel according to the invention incorporating the keel construction variant C;

> Fig. 2 A perspective of three basic keel construction variants (A, B and C), whose common feature are the foils of the movable part of the keel which are in a fixed position to each other under a certain angle. The variants A and B are shown in neutral position, while variant C is shown in the extreme sailing position;

> Fig. 3 Three basic keel variants from the Fig. 2 as viewed from the front;

> Fig. 4 An individually represented frontal perspective of the variant B construction of the keel according to the invention incorporating presentations of the angle δ of the articulated part of the foil 230, 231 in relation to elementary surface of the foil 213, 223 and of the angle between the foils which are to each other in fixed position φ;

> Fig. 5 An individually represented variant C (the same for B and D) construction model of the keel according to the invention as viewed from the front incorporating the presentations of the angle of the pivot axis α and of the angle of the articulated part of the foil β in relation to the parallel with the water line 201 when the aforementioned foil is in vertical position.

> Fig. 6 A perspective of the variant D construction of the keel according to the invention incorporating all basic positions of the between each other separately rotatable foils;

> Fig. 7 A frontal view of the variant D of the construction of the keel according to the invention built in the vessel incorporating all basic positions of the between each other separately rotatable foils. The drawings IDd and IDe show the positions of the keel 1 when the vessel is planing and the whole hull of the vessel 50 is above the waterline 200, while the drawings IDa and IDb present the keel in its normal position;

> Fig. 8 A perspective of the individually represented variant D construction of the keel according to the invention in its dropped position IDa, intended for entering marina or when the vessel is moored;

> Fig. 9 A presentation of the inbuilt keel from the Fig. 8;

> Fig. 10 A perspective of the individually represented variant D construction of the keel according to the invention with the neutral position of the foils (90°, position IDb), intended for leaving the vessel ashore or on the sea floor at low tide;

> Fig. 11 A presentation of the inbuilt keel from the Fig. 9;

> Fig. 12 A perspective of the individually represented variant D construction of the keel according to the invention incorporating foils in approximately extreme sailing position IDe, intended to weigh the vessel down as much as possible in case of side wind that blows into the right side of the vessel and when the vessel is planing in favourable wind conditions;

> Fig. 13 A presentation of the inbuilt keel from the Fig. 12;

> Fig. 14 A perspective of the individually represented variant D construction of the keel according to the invention in its extreme raised position IDe, intended to enter shallow waters or to start motor-sailing (planing);

> Fig. 15 A presentation of the inbuilt keel from the Fig. 14;

> Fig. 16 A view of the inbuilt variant D construction of the keel according to the invention from the bottom rear right side of the vessel in all the basic positions of the between each other separately rotatable foils;

> Fig. 17 A schema of the keel construction with the hydraulic motor and the planetary reduction gear that rotate the movable part of the keel and hydraulic pistons for leaning the flaps - an exploded drawing;

> Fig. 18 A presentation of the rotatable set of the fixed and movable part of the keel for the construction variants A, B in C, whose common characteristic is that both foils of the movable part of the keel 2 are in between each other fixed position, while the rotatable socket 20 of the movable part of the keel is made up of one piece and attached to the pivot axis 100 of the geometrical axis of the keel;

> Fig. 19 A presentation of the rotatable set of the fixed and movable part of the keel for the construction variant D, where the position of each foil of the movable part of the keel 2a in 2b is independent in relation to each other since each foil together with the belonging partial socket 20a and 20b is independently attached to the pivot axis 100 of the geometrical axis of the keel.

The keel 1 according to the invention comprises the rigid part 10 which is fixed to the hull 50 of the vessel 5 and the around its axis 100 rotatable part 2 (or 2a and 2b with variant D), which is attached to the rigid part and comprises firmly to each other connected foils that point apart and are at right angles to each other or completely independently rotatable foils 21, 22, in relation to each other, which comprise a ballast mass or a weight 211, 221 at their final free parts 210, 220.

Like with hitherto known keels also this keel's fixed part 10 is constructed as a rigid, appropriately hydrodynamically designed part with the preferably symmetrical cross section that is in relation to its starting position put vertically and runs in direction of the hull 50 of the vessel 5 vertically downwards. A starting position of the part 1 is in this case the position of the keel 1 of the wind- powered vessel on the completely level and calm waterline (the so called ideal waterline). The fixed part 10 is firmly attached to the hull 50 of the vessel 5 and relatively short and consequently exposed to relatively small bending loads and deformations. That is why also the draft of the vessel 5 can be smaller than it usually would be with the classical keel. The vessel 5 can therefore sail and be maneuvered also in shallow waters.

When the vessel is in the starting position 5, this means on ideal waterline, the longitudinal axis 201 of the vessel 5 is defined at the free end 110 of the fixed part 10 of the vessel 1. The aforementioned longitudinal axis coincides or is at least parallel with a certain sailing direction or movement of the vessel or to the longitudinal symmetrical axis of the vessel 5 and at the same time also to the ideal waterline.

At the free end 10 of the fixed part 10 (Fig. 2) of the keel 1 a case 12 is provided, in which the geometrical axis 100 of the keel 1 with the inclination angle α (Fig. 5) in relation to the axis 201 of the vessel 5 is positioned. The bearing socket 20 of the movable part 2 of the keel 1, which is positioned in the case 12 of the fixed part 10, is driven by the chosen propulsion device 14 (Fig. 17), preferably the hydraulic motor and planetary propulsion device and a break, and can be steered via steering device (no drawing) which is via communication connection device (no drawing) connected to at least one steering device (no drawing) in the area of the managing desk of the vessel 5. The socket 20 is firmly attached to both foils 21, 22, which can thus be firmly connected, either each separately (Fig. 19) or at first with each other (Fig. 18) and then via socket 20, or via partial socket 20a and 20b to the geometrical axis 100.

The geometrical axis 100 of the keel 1 runs obliquely at an angle α in relation to the axis 201 of the vessel 5, so that the axis 100 of the keel 1 is obliquely inclined downwards in direction from the bow 51 to the stern 52 of the vessel 5, or so that in direction towards the bow 51 of the vessel 5 the axis 100 nears the waterline and in direction towards the stern withdraws from the waterline. The aforementioned angle α is preferably approximately 1.5°. The aforementioned case 12 is hydrodynamically shaped, so that e.g. the frontal part 121 is hemispherical, while the rear part 122 has a conoidal shape. Furthermore, the socket 20 or partial socket 20a, 20b of the rotatable part 2 which is positioned between both parts 121, 122 in the case 12 forms together with these parts 121, 122 as symmetrically as possible shaped and floatable surface which is acceptable in terms of hydraulics.

Also both of the foils 21, 22 of the rotatable part 2 that are attached to the aforementioned socket 20 (20a, 20b) are constructed with the hydrodynamically designed and preferably symmetrical cross sections, whereby each of foils 21, 22 on its free end 210, 220 comprises a hydrodynamically shaped weight 211, 221.

One of the possible constructions of the keel IA according to the invention proposes a flap 215, 225 (Fig. 2 and 3) positioned on the outer, outwards or from the other foil 21, 22 always aside directed part 213, 223 of each foils 21, 22. The flap can either be perpendicular to each of the belonging foils 21, 22 or at a different angle, in particular at an angle of 90° in relation to the other foil 21, 22, and preferably positioned on the third of the distance between the socket 20 and the free part 210, 220, or with the weight 211, 221 of the foil 21, 22.

A further possible construction of the keel is a variant IB, as shown in Fig. 2, 3 and 4. In this case each of both foils 21, 22 are basically at least approximately L-shaped, again with the hydrodynamically and symmetrically designed cross section, so that the articulated parts 210, 220 point outwards and are either cut at right angles to the longitudinal surface of the foils 21, 22 or at a different angle, in particular e.g. at an angle of 60° (Fig. .4 - δ), in relation to the longitudinal surface of the foils 21, 22. Moreover, the free articulated parts 230, 331 are additionally rotated on the elementary surface of the keel's foils at a smaller angle, preferably 3° upwards from the stern to the bow, and equipped with the weights 211, 221. Foils can either be articulated in an acute angle or circularly with an optional radius (no drawing).

The aforementioned variant in certain sailing conditions enables to reduce the drag; when one of the weights 211 or 221 is above the waterline, dynamic drag of the weight of the foil which is in the lifted position is reduced. Since the frontal drag is lowered on the side of the vessel, also the side swaying (heeling) of the vessel in vertical axis is reduced. Because of the incline of the articulated part of the foil which is in a certain moment in the vertical position, hydro dynamic buoyancy which appears on the articulated part of the foil (230 or 231) additionally lifts the vessel and at the same time rotates it around its longitudinal axis in an opposite direction to that of the lateral winds in the sails. This additionally increases equalization force of the vessel since this force is correlated with the horizontal speed of the vessel.

Figures 1, 2, 3 and 5 depict the construction variant C of the keel according to the invention, where both foils, 21 and 22, are again firmly attached to each other via socket 20, which is flexibly attached to the rigid part 10, so that it can still be rotated around the axis 100. Each foil 21, 22 positioned near the aforementioned socket 20 is equipped with the flap 216, 226. Each flap 216, 226 is rotatable around the axis 217, 227 (Fig. 17) which runs longitudinally in relation to the each foil 21, 22 and can be rotated around the aforementioned axis 217, 227 by means of appropriate propulsion device 218, 228, in particular e.g. a hydraulic piston which can be incorporated in the hydraulic circuit and in the steering and loading device of the aforementioned propulsion device 14.

When the keel 1 is in position from the Fig. 10 and 11, the weights 211, 221 are symmetrically positioned in relation to the longitudinal axis 201 of the vessel 5. This position of the keel 1 enables the vessel 5 to be put on a flat surface ashore, anchored in the sea or even sail, for example motor- sail. In such a case the draft of the vessel 5 is smaller and this enables sailing also in shallow waters. By using the propulsion device 14 the rotatable part 2 of the vessel 1 can, if needed, be rotated around the axis 100 of the keel 1 in relative relation to the rigid part 10. It is understandable that if the vessel 5 is supported on a flat or inclined sea floor in case of low tide via propulsion device 14, the side swaying or listing can be compensated and the vessel 5 can be put into the position where the rigid part 10 of the keel 1 is at least approximately vertically positioned.

While wind-sailing, the mast leans aside and consequently the vessel 5 starts heeling (it leans aside), or in other words rotates around its longitudinal axis 201 because of the drag in the sails. This turn can be reduced or, if necessary, even overcome by turning the part 2 of the keel 1 at least approximately into the position depicted in Fig. 1 and 13.

In such a position the keel performs a double function; one of the foils 21 comprising a weight 211 on its free part 210 forms a lengthening of the rigid part 10 in direction from the waterline towards the sea floor and represents the drag that opposes the side drift of the vessel and simultaneously with the articulated part of the foil 231 with a help of hydrodynamic force rotates the vessel in the opposite direction to the side wind since its angle functions as a propeller. In the meantime, the other foil 22 on the windward side of the vessel is positioned approximately horizontally and carries the weight 221 on a relatively long lever foil from the axis 201 of the vessel 5 and creates additional torque that is opposite to the direction of the torque which is created on the mast in the area of sails by the wind force. This fundamentally reduces the listing and balances the vessel while sailing and contributes to higher wind force efficiency and to the comfort. It is understandable that the movable part 2 of the keel 1 can optionally be rotated around its axis 100 by the propulsion device and moreover, even automate the rotation of the part 2 of the keel 1, so that on the basis of the measured parameter values or signals from the appropriate sensors the steering device automatically controls and maneuvers the propulsion device 14 and consequently also the turning of the part 2 of the keel 1 in each case to the appropriate extent in either direction.

Accordingly, also the swaying of the moored vessel due to the wave motion can be reduced with the appropriate steering, whereby the turns around the axis 201 of the vessel 5 due to e.g. side waves can regularly and promptly be automatically compensated by properly turning the part 2 of the keel 1.

It can also be understood that even if the vessel due to the tide, or because it is not anchored properly or for some other reasons runs aground and the keel starts hitting against the ground due to the wave motion, a simple partial turn of the movable part of the keel 2 in either side enables to slightly lift the stranded vessel and neutralize destructive hitting against the ground and simultaneously via propulsion device and either the helm or the rudder turn the vessel around the vertical axis of the area where the lowered foil of the keel (211 or 221) touches the ground, put the keel into its neutral (Fig. 4) or lifted (Fig. 14) position and with the help of propeller and the engine push the vessel to the deeper water area, where you can either anchor or sail.

One of the main advantages of the keel 1 according to the invention is that it creates relatively strong hydrodynamic buoyancy while sailing at high speeds. As mentioned, the longitudinal axis 100 of the keel 1 in relation to the longitudinal axis 201 of the vessel 5, or of the waterline 200 is inclined at an α angle. At higher speeds, e.g. when sailing in favorable wind conditions, either foil 21, 22 which is positioned approximately horizontally below the waterline with a help of the articulated part of the foil 230, 231, which is positioned deeper in more stable water mass, functions as an aircraft wing and creates relatively strong dynamic buoyant force, which is opposite to the force of gravity. Dynamic buoyancy gradually lifts the vessel and consequently the drag of the vessel with the surrounding water mass is diminished and the speed of the vessel is additionally increased. In optimal sailing conditions this type of synergy results in the vessel's planing, which drastically reduces the drag and fundamentally increases the speed. It should be noted that for such cases at least one directional stabilizer 55 (Fig. 1) has to be provided on the hull 50 of the vessel 5 next to the aforementioned keel 1 since it ensures the maneuvering of the vessel 5 in the desired direction and prevents the rotation of the vessel 5 around its vertical axis.

With the variant D, Fig. 6 to 16 and 19, of the keel according to the invention all aforementioned positive effects of the keel variants A, B or C are additionally strengthened since the movable part of the keel 2 no longer comprises only one basic element where the foils are fixed to the bearing socket 20 of the pivot axis 100, but each foil (2a and 2b) can be rotated individually around its (the same one) geometrical axis, which provides higher flexibility and usefulness of the keel in different sailing conditions or when mooring the vessel or when the vessel runs aground (due to the tide).

Fig. 6 depicts all the basic positioned of the keel variant D.

Position IDa shown in Fig. 8 and 9 depicts the lowered foils of the vessel. This position is intended for entering the marina, where the underwater part of the keel has to be as narrow as possible to avoid other vessels, ropes or other underwater obstacles.

Position IDb shown in Fig. 10 and 11 depicts the foils of the keel at approximately right angles to each other (90°), whereby each of the foils is at an angle of approximately 45° in relation to the waterline. This position is intended for leaving the vessel ashore, or if the vessel (partially) runs aground e.g. due to the low tide and also when motor-sailing if planing is not desired.

Positions IDc and IDd, the latter shown in Fig. 12 and 13, depict the foils of the keel at approximately right angles to each other (90°), whereby one of the foils is positioned completely horizontally and the other completely vertically. This position is intended for sailing in mainly side winds, in the example shown from the right side. In favorable sailing conditions this position enables the vessel 50 to lift from the water and start planing on the underwater wings.

Position IDe, shown in Fig. 14 and 15 depicts the foils of the keel positioned approximately at an angle of 180° to each other, whereby both foils are parallel with the waterline and both ballast mass weights are pushed out of the water in order to reduce the frontal water resistance (drag) as much as possible. This position is intended solely for motor-sailing. If the engine pushes the hull of the vessel 50 strongly enough, the vessel lifts from the water and starts planing on the underwater wings. This enables the vessel to enter the most shallow water areas.

The keel variant D is technologically the most demanding one since it requires two separate propulsion elements and more demanding steering device, which additionally controls the movement of both foils (21, 22). Also sealing and additional construction which is needed for maneuvering the flaps 215 and 225 are more demanding due lack of space. On the other hand, this keel variant offers additional advantages which raise the level of universality of the new vessel.

Claims

1. A keel of the wind-powered vessel (5) comprising appropriately rigid and with the hull (50) of the vessel (5) firmly connected fixed part (10) with the particularly hydrodynamically and symmetrically designed cross section in relation to the streamlines that run in the longitudinal direction between the bow (51) and the stern (52) of the vessel (5), whereby the aforementioned part (10) is positioned below the waterline and at least approximately below the center of gravity of the vessel (5), whose current sailing direction is each time defined with the longitudinal axis (201) of the vessel (5), characterized in that next to the aforementioned rigid part (10) comprises a rotatable part (20) comprising two with each other firmly connected V-shaped foils that point apart and are at least approximately at right angles to each other (21, 22), or two separate in the same longitudinal axis rotatable foils, with the hydrodynamically and particularly symmetrically designed cross section, that are around the geometrical axis (100) of the keel (1) in the area of its free part (110) rotatably connected to the rigid part (10), so that each of the foils (21, 22) can optionally be turned from the vertical to the horizontal position or vice versa, or held in a certain position by using appropriate propulsion device, whereby at the free end (210, 220) of each of the foils (21, 22) at least one firmly fixed and hydrodynamically designed weight (211, 221) is proposed.

2. A keel as claimed in claim 1, characterized in that at the free end (110) of the rigid part (10) a case (12) is proposed, through which the aforementioned geometrical axis (100) of the keel (1) runs in its longitudinal direction, around which rotatable foils (21, 22) are positioned.

3. A keel as claimed in claims 1 or 2, characterized in that the foils (21, 22) are depending on the variant either fixed to the socket (20) and by that separately firmly connected to each other and jointly rotatable around the geometrical axis (100) in the area of the aforementioned case (12) and thus via socket (20), or independently connected to the partial sockets (20a, 20b) and thus independently rotatable around the same geometrical axes (100).

4. A keel as claimed in claims 2 or 3, characterized in that the case (12) at the free end (110) of the fixed part (10) of the keel (1) comprises at least approximately hemispherically designed front part (121), at least approximately conoidal rear part (122) and the around its axis (100) rotatable socket (20) positioned between them in the case.

5. A keel as claimed in one of the claims from 1 to 4, characterized in that the propulsion device (14) for turning the foils (21, 22) around the axis (100) and/or holding the foils (21, 22) in a chosen position after the turn around the aforementioned axis (100) is positioned inside the case (12) and/or the socket (20).

6. A keel as claimed in claim 5, characterized in that the propulsion device (14) is realized by a hydraulic motor, a planetary reduction gear and a break or some other appropriate mechanical or mechanically hydraulic set.

7. A keel as claimed in any of the claims from 1 to 6, characterized in that the longitudinal axis (100) of the keel (1), around which aforementioned rotatable foils (21, 22) are positioned, runs obliquely at an angle α in relation to the longitudinal axis (201) of the vessel (5), which is parallel with the ideal waterline and coincides or is parallel with the sailing direction of the wind-powered vessel (5), so that the axis (100) of the keel (1) in direction towards the bow (51) of the vessel (5) nears the waterline and withdraws from the waterline in direction towards the stern (52) of the vessel (5).

8. A keel as claimed in claim 7, characterized in that the inclination angle (α) of the axis (100) of the keel (1) in relation to the axis (201) of the vessel (5) is between 0.5° and 5°.

9. A keel as claimed in claim 8, characterized in that the inclination angle (α) of the axis (100) of the keel (1) in relation to the axis (201) of the vessel (5) is between 1° and 3°.

10. A keel as claimed in claim 8, characterized in that the inclination angle (α) of the axis (100) of the keel (1) in relation to the axis (201) of the vessel (5) is at least approximately 1.5°.

11. A keel as claimed in any of the claims from 1 to 10, characterized in that each of the foils (21, 22) is at least approximately L-shaped, so that the articulated, with appropriate weights (211, 221) equipped free parts (210, 211) of the foils (21, 22), point outwards and are either at least approximately at right angles to each other (φ), or rotatable independently of each other in the same longitudinal axis (100), whereby the angle between their internal surfaces is arbitrarily adjustable in the range of approximately 10° to 200°.

12. A keel as claimed in any of the claims from 1 to 10, characterized in that each of the foils (21, 22) is at least approximately L-shaped, so that the articulated, with appropriate weights (211, 221) equipped free parts (210, 211) of the foils (21, 22), point outwards, whereby each of them is in relation to the surface of the belonging foil (21, 22) positioned at an angle (δ) which is at least approximately 60°.

13. A keel as claimed in any of the claims from 1 to 10, characterized in that each of the articulated parts of the foils (230, 231) is additionally rotated on the elementary surface of the foil (213, 223) of the keel, so that the front part of the joint nears the pivot axis (100), while the rear part withdraws from it and that the aforementioned angle β is between 0.5° and 7°.

14. A keel as claimed in claim 13, characterized in that each of the articulated parts of the foils (230, 231) is additionally rotated on the elementary surface of the foil (213, 223) of the keel, so that the front part of the joint nears the pivot axis (100), while the rear part withdraws from it and that the aforementioned angle β is between 1° and 5°.

15. A keel as claimed in claim 13, characterized in that each of the articulated parts of the foils (230, 231) is additionally rotated on the elementary surface of the foil (213, 223) of the keel, so that the front part of the joint nears the pivot axis (100), while the rear part withdraws from it and that the aforementioned angle β is at least approximately 3°.

16. A keel as claimed in any of the claims from 1 to 15, characterized in that each of the aforementioned foils (21, 22) can be equipped with at least one flap (216, 226) in the area by the socket (20) and at the rear part in relation to the streamlines that run in the longitudinal direction from the bow (51) to the stern (52) of the vessel (5).

17. A keel as claimed in claim 16, characterized in that each of the flaps (216, 226) can optionally be either rotated around the axis (217, 227) which runs longitudinally between the axis (100) and the free part (210, 220) in relation to the belonging foil (21, 22), or held in a chosen position by the appropriate propulsion device (218, 228).

18. A keel as claimed in claim 16, characterized in that the propulsion device (218, 228) is realized by a hydraulic cylinder.

19. A keel as claimed in claims 6 and 18, characterized in that the hydraulic motor with the planetary reduction gear or some other appropriate mechanical or mechanical hydraulic propulsion device (14) for shifting the foils (21, 22) and the hydraulic cylinders (218, 228) for moving the flaps (216, 226) are hydraulically connected into appropriately steered mechanical hydraulic set.

20. A keel as claimed in claim 19, characterized in that at least the propulsion device (14) for shifting the foils (21, 22) can optionally be automatically controlled on the basis of the each time separately chosen parameters, in particular periodically repeated listing of the vessel (5) around its longitudinal axis (201) because of the turbulent water.

21. A wind-powered vessel comprising a hull (50) with a mast (53), sails (54) and a rudder (56), characterized in that it comprises a keel (1) as claimed in aforementioned claims which is positioned on the hull (50) and at least approximately below the center of gravity of the vessel (5).

22. A wind-powered vessel as claimed in claim 21, characterized in that the hull (50) is at an adequate distance from the keel (1) to the bow (51) equipped with at least one directional stabilizer (55) that maneuvers the vessel (5) in direction which is parallel with the longitudinal axis (201) of the vessel (5) and prevents the vessel to turn around the vertical axis of the keel (1).

23. A directional stabilizer as claimed in claim 22, characterized in that it comprises vertical fin (55a), which provides stability for the vessel movements around the vertical axis, and a horizontal fin (55b), which is symmetrically transversal and perpendicular to the vertical fin (55a) and positioned approximately in the middle of the height of the vertical fin (55a) and in transversal direction parallel to the waterline and inclined in longitudinal direction, so that it nears the waterline (200) in direction towards the bow of the vessel and withdraws from the waterline in direction towards the stern of the vessel, whereby the longitudinal inclination angle (ω) of the horizontally positioned fin (55b) is in general between 1° and 9°, preferably between 3° and 6° and in particular at least approximately 5°, so that at sufficient horizontal speed, hydrodynamic buoyancy that is needed for the vessel to start lifting the bow towards the waterline (200) is provided and thus temporarily the relative angle of incidence of the keel (100) in relation to the waterline (200) is increased, which results in larger hydrodynamic buoyant force on each of the approximately horizontally positioned foils of the keel (21, 22) and enables the vessel (5) to lift to the point where the fin (55b) reaches the waterline (200) and additional lifting is disabled; this lessens the angle of incidence of the keel (1) to such an extent that the resultants of the hydrodynamic buoyant force on the keel (1) and of the weight of the vessel (5) equalize.