Patent Application
20250010959
This invention relates to the field of boats, in particular offshore sailboats, and concerns a system of articulated fins that may be moved between a folded position and a deployed position, and vice versa.
The present invention therefore relates to boats, in particular offshore boats, such as large sailboats or cruise ships designed to cover long distances. As is well known, this type of boat is configured so that its upper deck is high above the water and all of its decks remain as horizontal as possible, particularly with a list close to zero degrees. The aim is to ensure the comfort and the safety of passengers during periods of navigation that may last several weeks.
For example, these boats are generally equipped with transverse fins at the stern, whose lifting or diving incidence is automatically corrected to create a torque with a longitudinal axis to compensate for the listing effect caused by crosswinds.
We are also looking to improve the speed of the boats, particularly large ones. To this end, foil systems have been developed. For example, the latest racing sailboats are equipped with large foils, either sliding into curvilinear slots in their hulls or articulated above the waterline, with the aim of lifting their hulls completely out of the water and considerably increasing their speed. In operation, these large foils are partially submerged and partially gliding on the surface of the water. These foils are very bulky, whether in the deployed position or folded position. Such foils are also vulnerable, even dangerous, when sailing, in the event of a collision with any drifting object. Their overall dimension also makes them difficult to operate in harbors, and ill-suited to offshore leisure sailboats, as they are difficult to pilot and especially to operate, especially with a small crew. To be effective, these foils also require the structure and contents of the sailboat to be considerably lighter, so that it may be lifted almost completely out of the water.
These constraints are not compatible with offshore cruising sailboats, which are comfortable, autonomous, very solid in all wind and sea conditions, and generally operated by a small crew. This type of offshore cruiser boats is necessarily quite heavy, as it also has to carry a lot of equipment, such as furniture, generators, large-capacity batteries, heating and air conditioning systems, fridges and freezers, dishwashers and washing machines, etc.
Some offshore cruisers sailboats are nevertheless equipped with linear foils, extending transversely from the underside of the hull. These foils, which are shaped like straight blades, help to increase the sailboat's speed by sliding on the surface to lift the front of the sailboat out of the water, thereby reducing its resisting torque and wetted surface area. But steering these sailboats is tricky, because of the wave disturbances on the foils, which also cause a lot of spray. Moreover, the incidence of these linear foils is not adjustable, as they are constrained by the slot in which they move to extend or retract into the hull. Finally, as these foils are almost perpendicular to the boat's longitudinal axis and to the direction of travel, they remain particularly vulnerable to drifting objects encountered during sailing, which may get caught (nets, ropes, branches, plastic film, buoys, etc.) or cause damage to the hull in the event of a violent impact.
It should also be noted that, in the case of boats of the offshore sailboat type powered by the veiling force, the latter have a high center of sail, in particular 30%-40% of the height of their mast. This has several effects on the point of sail of these offshore sailboats. Firstly, this high center of sail contributes to list the boat over, which reduces the veiling force, despite the compensating effects of the keel. When listing, the center of sail shifts to downwind, which also contributes to making the boat rise towards the wind and become weather helm boat, as the saying goes; this tendency must be compensated for by balancing the sails and acting on the rudder, which slows the boat down. Lastly, the high sail area of the offshore sailboats also causes the bow to sink, which generates violent braking in swells or waves, especially when the point of sail is not downwind, which delays or compromises it ability to lift off, i.e. to “glide”, and therefore to accelerate beyond her theoretical speed limit.
The aim of the present invention is to remedy at least some of the above-mentioned disadvantages and thus to allow an offshore boat, in particular an offshore cruising sailboat, which is comfortable, safe and very well equipped internally, to increase its speed substantially, in particular by a further 2 to 8 knots, while reducing its list and its drift on non downwind points of sail, and while making it easier to steer, despite a reduced crew.
In this context, the system proposed in this document allows to reduce the list to increase the veiling force, to increase the anti-drift surface to improve, in other words reduce, the heading when sailing close-hauled, to pass better through the waves by raising the front of the sailboat and taking its bow out of the water, to reduce its tendency to pitch on each wave, to trigger any lift off sooner, thanks to a maximum support on the flat shape of the rear of the hull, and to make the boat's point of sail more stable by reducing the effect of rising into the wind (weather helm), or falling (lee helm) at all points of sail, whether downwind or not downwind.
More specifically, the invention relates to a system of articulated fin for a boat having a hull, the system of fins comprising at least two fins having a respective end fastened to an element of the hull of the boat, the two fins being located one on each side of a longitudinal axis of the boat, each fin being configured to be completely submerged in a deployed position of the fin, each fin also having a folded position in which the fin is configured to bear against the hull of the boat, and each fin having operating means configured to move the fin between the folded position and the deployed position and vice versa.
In addition, each fin comprises a web, in particular made of titanium, and a working portion fastened to the web by means of fastening means, the web being fastened securely to the operating means. In particular, this allows to have a fin web made of a very hard material, such as titanium, and a working portion enveloping it, which may be made of a strong synthetic material or carbon, which is lighter than the material making up the web. The working portion may or may not be in one piece.
Each fin has a leading edge, i.e. facing the bow of the boat, which may be curved rearwards in particular, so as to give the fin the shape of a shark's or dolphin's pectoral fin. This shape means less impact and less risk of a drifting object, such as a net, getting caught and stuck, as the rearward curved shape of the front edge facilitates the evacuation of such objects which slide, if necessary, along the front edge of the fin and are evacuated towards the rear.
In an advantageous embodiment, the fastening means are fusible; for example, they may be pins or screws or bolts configured to perform a fuse function.
In particular, the fins allow to lift the bow of the boat, so as to lift out of the water to improve the boat's speed, while ensuring its stability and that of its heading.
In one embodiment, each fin has a shape adapted to match a predefined shape of the hull of the boat, in the folded position in which the fin is pivoted to bear against a side flank of the hull of the boat.
Preferably, each fin comprises an anti-listing portion having a lifting surface and an anti-drift portion, the anti-listing portion being substantially horizontal and the anti-drift portion being substantially vertical when the fin is in the deployed position.
In one embodiment, for each fin, the operating means comprise pivoting means comprising at least one pivot, adapted to pivot the fin about a pivot axis, between the folded position and the deployed position and vice versa.
Advantageously, the pivoting means are configured to be fastened to a lower part of the hull, between the keel and the chine of the boat.
This ensures that the fins are always working while submerged, when they are in the deployed position.
In particular, for each fin, the operating means comprise means for moving the pivot axis of the fin, configured to modify the incidence of the fin.
The system of fins according to the invention may also comprise control means configured to keep the anti-listing portions of the fins horizontal.
In particular, for each fin, the fastening means are fusible and may be configured to the working portion to be separated from the web, either automatically or in a controlled manner.
In particular, each fin may comprise a cable connecting the working portion to the web, the cable being configured so that, when the working portion is separated from the web, the cable pulls the working portion to the side and/or to the stern of the boat during sailing.
In one embodiment, each fin comprises locking means for locking an angular position of the fin between a plurality of positions comprising at least the folded position and the deployed position.
In one embodiment, the system of fins according to the invention may comprise backup means configured to automatically move each fin into a folded position.
The present invention also relates to a boat, in particular an offshore sailboat, comprising a hull having a flat rear portion, and a system of fins as briefly described above, the system of fins being fastened to the hull of the boat.
In one embodiment, the boat comprises a dado and/or a rabbet adapted to house at least a part of the thickness of each fin in a folded position in a recess in the hull.
According to the invention, the boat may further comprise electrical power generation means connected to the articulation and pivoting device, and configured to generate electrical power when the boat is at anchor.
According to an embodiment, the system of fins of the boat comprising a pair of front fins and a pair of rear fins, the front fins have a lifting incidence and the rear fins are configured such that, when the port front fin is in the deployed position and the starboard front fin is in the folded position, with the wind coming from the starboard side, then the starboard rear fin is in the deployed position and its incidence is adjusted so as to be diving, the port rear fin being in the folded position or in the deployed position with a lifting incidence, and, conversely, when the starboard front fin is in the deployed position and the port front fin is in the folded position, the wind is coming from the port side, so the port rear fin is in the deployed position and its incidence is adjusted so as to be diving, the starboard rear fin being in the folded position or in the deployed position with a lifting incidence. This improves the anti-list function of the rear fin, which lies to upwind and tends to “press” the stern of the boat, thereby making it easier for the boat to nose-up, and it improves the lifting of the front fin, which lies to downwind.
According to an embodiment, the boat having a waterline length, the respective incidence of the fins is configured to raise the bow of the boat, in particular 1% to 3% of the waterline length of the boat.
According to an embodiment, the system of fins comprising a pair of front fins, the pivot axis of the front fins is pinched forward, i.e. the pivot axes of the front fins on either side of the longitudinal axis of the boat converge forward. This allows to improve the anti-drift function of the front fins: downwind, only one front fin is deployed, so the pinching improves the anti-drift function.
Advantageously, the fins, which may be connected to the keel, are configured to rest on the bottom when the boat is grounded. One advantage of the invention is that it may be used in the event of partial or total grounding, particularly at low tide, while leaving the boat horizontal. This is because the fins hold the boat aground, while leaving the boat, which rests on the fins on the bottom, in a more or less horizontal position.
Advantageously, the fins are configured to be deployed at anchor, the system comprising at least one nitrogen ball connected to the articulation and pivoting device and configured to dampen the pivoting movements of the fins due to surf. One advantage of the invention is that it may be used at anchor. When in a deployed position, the fins dampen or even stop the roll caused by the surf when anchored outside of a port, by breaking any natural frequency.
According to an embodiment, the system of fins of the boat comprising a pair of front fins, the front fins generate a center of pressure participating in a bow lift of the boat located forward of a center of buoyancy of the boat, in particular located from 5% to 20%, for example from 8% to 10%, of the waterline length of the boat, forward of the center of buoyancy of the boat. This has a positive effect when the boat is listing: the center of pressure generated by the front fins is forward, generating a nose-up effect and compensating for the boat's lee helm.
The invention will be better understood on reading the following description, which is given solely by way of example, with reference to the annexed drawings, which are given by way of non-limiting examples, in which identical references are given to similar objects and in which:
It should be noted that the figures set out the invention in detail to allow the invention to be implemented, said figures of course being able to be used to better define the invention if necessary.
Preferably, the shape of the fins 10, 50 is rounded so as to reduce the intensity of any impacts with floating objects, as will be described in more detail below. The rounding may be seen in [
With reference to [
According to the embodiment shown in [
With reference to the embodiment shown in [
With reference to the embodiment shown in
In one embodiment, when the pins 12 act in this way, like fuses, by releasing and allowing the working portion 100 to become separated from the web 11, a spring may be provided, fastened to the web 11 or to the hull 2, compressed by default when the working portion 100 is nominally fastened to the web 11, the spring decompressing and thus pushing the working portion 100 away from the hull 2 of the boat 1 so as to avoid any impact between the working portion 100 and the hull 2 during separating. The description in
As shown in [
Preferably, the fins 10 are fastened to the hull 2 between the chine and the keel 5, as shown in [
In particular, the fins 10, 50 are fastened to the hull 2, on either side of the longitudinal axis D of the boat 1, which passes through the keel 5, the device for fastening and articulating each fin 10 being located in the housing 19 provided in the hull 2, above the keel 5 and close to it. For example, the fins 10, 50 are fastened approximately halfway between the keel 5 and the side chine of the hull 2 of the boat 1, on each side.
The housing 19 of each fastening and articulation device is designed not to take up any useful volume and is preferably located under the inside floor of the sailboat, as in [
The fins 10, 50 work, as already indicated, always completely under the surface of water when they are in deployed position.
In addition, the distance of the fins 10, 50 from the surface of the water, at depth, avoids any cavitation leading to loss of lift, and does not generate spray. In this way, by tending to keep the anti-list portion 102 parallel to the surface of the water, the underwater lift produced mainly by the anti-list portions 102 of the fins 10 is maximized, as they are not disturbed by the effects of waves or swell.
In addition, the anti-drift portions 101 of the fins 10, 50, corresponding to the substantially vertical part of the fins 10 in the deployed position, form a substantial anti-drift surface and thus provide an anti-drift function. In this way, the anti-drift portion 101 of each fin 10 helps to stabilize the heading of the boat 1.
In one embodiment, the anti-drift portion 101 of each forward fin 10 may be designed to form an angle pinched forward equivalent to the natural drift of the hull 2, so that the boat tends to move forward strictly along the longitudinal axis D of its hull 2, which improves its upwind performance in particular. In other words, the pivoting axes X of the front fins 10 form an angle converging towards the front of the boat 1.
The device for fastening and articulating the fins 10, 50 comprises means for operating 31, 32, 33, 34, 35 the fins 10, 50. The operating means comprise pivoting means for pivoting the fins 10, 50 about a pivoting axis X substantially parallel to the longitudinal axis D of the boat 1. In particular, each fin 10 may move between a deployed and a folded position, and vice versa, by pivoting.
In the folded position, the fin 10, 50 bears against the side flank 21 of the hull 2, following its shape. On the other hand, in the deployed position, the fin 10 extends in a direction mainly transverse to the longitudinal axis D of the boat 1. The working portion 100 is completely submerged and the anti-list portion 102, whose lifting surface, is substantially horizontal, in other words parallel to the surface of the water, while the anti-drift portion 101 is substantially vertical, in other words orthogonal to the surface of the water.
The pivot axis X, which is substantially parallel to the longitudinal axis D of the boat 1, may be moved slightly downwards or upwards, as shown in the examples in
In particular, by adjusting the location of the pivoting means and the direction of the pivoting axis X, it is possible to adjust the angle of incidence of the anti-list portion 102 relative to the horizontal or relative to the orthogonal to the flank of the boat 1. To this end, for each fin, the operating means comprise means for moving the pivot axis X of the fin 10. These means for moving the pivot axis X may, for example, consist of bearings 36 articulated via bearing axial movement means 33, which may comprise a motor coupled to an endless screw or cylinders, as shown in [
In one embodiment, when the system of fins comprises front fins 10 and rear fins 50, the incidence of the front fins 10 may preferably be adjusted as lifting. The incidence of the rear fins 50 is then adjusted accordingly, depending on where the wind is coming from and therefore on the deployed or folded position of the port and starboard front fins. So when the wind comes from the starboard side, the port side front fin 10 is in the deployed position and the starboard side front fin 10 is in the folded position. The port forward fin 10, which is lifting and in the deployed position, has an angle of incidence that makes it lifting. As a result, the starboard rear fin 50, which is upwind, is deployed and has a diving incidence, while the port rear fin 50 is in a folded position or in a deployed position with a lifting incidence. The starboard rear fin 50, which is upwind and in the deployed position, with a diving incidence, helps to promote the nose-up of the boat 1 by pressing the boat against the water and also contributes to the anti-list function.
Of course, the configuration is reversed when the wind comes from the port side.
It should also be noted that, in the event of a tailwind, the front 10 and rear 50 fins may be completely deployed with their incidence adjusted to be lifting or, alternatively, in the case of the rear 50 fins only, with their incidence adjusted to be diving, so as to “press” the boat down on the water and thus make it easier to get out of the water.
In one embodiment, sensors are provided to measure the stresses exerted on the structure of the boat 1, for example sensors measuring the intensity of a force exerted on the shrouds. Automatic or manually triggered backup means may therefore be provided to move one or more fins 10, 50, which were in the deployed position, into the folded position in the event of stress exceeding a predefined intensity threshold or in the event of listing exceeding a predefined limit listing threshold. In addition, the backup means may be used to modify the incidence of the fin or fins 10, 50 in the deployed position to make them more or less lifting or more or less diving.
With reference to [
As shown in [
Still referring to [
The fins 10, 50 also reduce the listing and help to increase the veiling force, and therefore the speed of the boat 1, by means of the anti-listing function provided by the anti-listing portion 102 of each fin.
Similarly, the optional auxiliary fins 50, i.e. the rear fins 50 visible in
The web 11 already briefly described above is made of metal, for example titanium. The web 11 forms the “core” of each fin. The web 11 is thus the fin element 10, 50 which is pivotally mounted. The web 11 thus has a pivot axis X substantially parallel to the longitudinal axis D of the boat 1. In the case where the structure of the fin 10, 50 does not comprise a web, the fin 10 being directly articulated by means of a fastening and articulation device, the fin 10 comprises the pivot axis X.
The pivot axis X, already introduced earlier, is produced, for example, by means of two pivots respectively at the front and rear of the web 11, as shown in [
In one embodiment, the system of fins 10, 50 comprises locking means 35 for locking each fin 10, 50 in the deployed or folded position respectively. These locking means 35 take the load off the pivoting means and may have several locking positions between the two extreme positions, i.e. the deployed position and the folded position of the fins 10, 50. According to one embodiment, for each locking position, the locking means 35 form a flexible, in other words damped, abutment, i.e. for example an elastomer abutment or an abutment connected to a nitrogen ball connected to a hydraulic circuit of the operating means. This reduces the stresses on the hull and improves the comfort and the flexibility of the system of fins.
The web 11 may thus be immobilized by locking means 35 in several positions, comprising at least the folded position and the deployed position for sailing.
According to one embodiment, control means, for example gyroscopes, are also provided to keep the anti-listing portions 102 of the fins 10, 50 horizontal, i.e. parallel to the surface of the water when the boat is sailing, so that they remain well submerged, parallel to the surface of the water, whatever the list of the sailboat.
In one embodiment, in order to adjust the incidence of the fin, in particular of the anti-listing portion 102, an articulated bearing 36 may be provided, on which each pivot, front and rear, is mounted. Each articulated bearing 36 then allows the pivot axis X to be translated in a slot, in particular a vertical slot, substantially perpendicular to the portion of the hull 2 where this articulation is located, for example by means of a cylinder or a screw, as shown in
As may be seen in [
The rearward-curved shape of the front edge of the fin, in particular the anti-listing portion 102, prevents drifting objects such as plastic bags, branches, seaweed, ropes, nets, buoys, etc. from getting caught while sailing.
In one embodiment, the anti-listing portion 102 also has a profiled shape, like an aircraft wing, so as to improve its lifting.
The working portion 100 of the fin 10, 50 is preferably made of a very strong synthetic material, for example carbon, and is notably lighter than the metal web 11 so as not to make the sailboat unnecessarily heavy. In particular, at least the anti-listing portion 102 is made of a highly resistant synthetic material, for example carbon.
The working portion 100 partially or even completely envelops the web 11, in particular the metal web, to which it is fastened by the pins 12 visible in [
In practice, in order to move a fin 10, 50 from the folded position to the deployed position, it may first be unlocked by actuating the locking means 35 in this direction, and then given a zero or slightly negative incidence to facilitate its descent, by means of a move of the pivoting axis X. The fin is then pivoted by the pivoting means to the deployed position. The fin 10, 50 is then locked in the desired deployed position by means of the locking means 35, so as to inhibit pivoting, and is then given a desired incidence, positive neutral or negative.
Conversely, to move a fin 10, 50 from the deployed position to the folded position, it may be given zero incidence, then unlocked, then possibly given a slight positive incidence to facilitate its ascent. Finally, it may be rotated to its folded position before being locked in this position. To facilitate folding, a return spring 320 may be provided which rests, for example, on the inner protrusion 110 of the web 11, as shown in [
Another advantageous use of the system of fins according to the invention is when the boat is at anchor.
In the deployed position, one or more fins 10, 50 ensure the boat's stability at anchor. By breaking any natural frequency of oscillation of the boat 1, the system of fins allows to dampen, or even stop, the roll caused by the surf.
According to this embodiment, there is also at least one nitrogen ball connected to the hydraulic means for operating the fins 10, 50 of the system of fins and configured to dampen any movement of the fins 10, 50, particularly when they are used at anchor, or when sailing, to dampen the impact of waves. In this case, the pivoting means of the fastening and articulation device connecting each fin 10, 50 to the hull 2 have a degree of freedom configured so that the fin 10, 50 may pivot under the effect of the surf, when it is in the deployed position, the pivoting being damped by said nitrogen ball.
According to another implementation of the system of fins according to the invention, the fins 10 are used so that they rest on the bottom in the event of total or partial grounding. Thanks to the fins 10, in such a grounded situation, the boat is held substantially in a horizontal position.
In a non-illustrated embodiment, the fins 10 are fastened to the keel, in particular on either side of the ballast of the keel 5. In this case, the keel 5 is considered to be part of the hull of the boat 1. In this embodiment, the fins 10 are deployed on either side of the keel 5 (which then forms part of the hull 2 of the boat 1) and provide the anti-listing and anti-drift stabilizing function described above. In addition, the fins 10 perform a stabilizing function at anchor to counter the roll caused by the surf, which is more advantageous because it is less bulky than when the fins are fastened to the hull 2 at a distance from the keel 5.
On the other hand, all or some of the means for operating the fins 10, 50, which combine the means for moving the pivot axis X and the means for pivoting each fin 10, 50, may be manual, or hydraulic, comprising hydraulic cylinders 32 and/or rotary or electrical motors, comprising screw-nut assemblies, which may be coupled to a return spring 320, and/or an endless screw 310 mounted on gear teeth or a rotary motor 31, or pneumatic, for example. Preferably, the operating means may be controlled, or at least activated, preferably remotely by means of electric buttons that may be controlled from a boat steering station. In one embodiment, the various successive means for operating the fins 10, 50 are controlled automatically, using a computer or programmable logic controller for example.
Alternatively or additionally, or as a degraded mode, manual auxiliary operating means may be provided, such as a winch crank, a manual hydraulic pump, etc., to move the pivot axis X and/or pivot the fins 10, 50.
According to one embodiment of the invention, there is also an energy recovery device adapted to produce electrical energy from the mechanical kinetic energy produced by the forces applied by the water to the submerged fins 10, 50 of the system of fins.
In particular, when at anchor, the fins 10, 50 may be in the deployed position, as already described, to ensure the boat's stability. In this configuration, the swell generates a rocking movement of the fins 10, 50 about their pivot axis X of the pivoting means of the fastening and articulation device which connects said fins 10, 50 to the hull 2 of the boat 1. The energy recovery device is connected to the pivoting means and converts the kinetic mechanical energy corresponding to the pendulum movement into electrical energy. For example, the mechanical kinetic movement is taken up by a cylinder and transferred to an alternator, which generates electrical energy.
The electrical energy generated in this way may be routed, for example, to an electrical system on the boat 1 comprising, for example, a voltage converter and a battery, the electrical energy being used to recharge the battery.
Thus, according to one embodiment, the means for operating the fins 10, 50 comprise a hydraulic operating cylinder. A three-way valve is then provided to switch between an operating position and an electrical power generation position in which each side of the hydraulic operating cylinder is connected to an element such as a piston, to generate electricity. For example, on each side of the operating hydraulic cylinder, a respective electric motor or hydraulic motor may be provided to drive an alternator adapted to generate electrical power when the operating hydraulic cylinder is moved, at anchor, due to the surf.
| Number | Date | Country | Kind |
|---|---|---|---|
| FR2112691 | Nov 2021 | FR | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2022/081559 | 11/10/2022 | WO |
