Patent Description:
Yachts may be desired to be sailed in a variety of wind conditions. A yacht is preferably able to be optimised for different conditions, in particular the sail area may need to be adjusted. Sails are generally of two basic constructions soft, fabric-shaped sails that are shell like, and wing sails which form a 3D cross section wing shape. Typically, a mainsail is reefed to decrease its sail area. A reef reduces the area of a sail, usually by folding or furling one edge of the sail in on itself. This may be achieved by retracting the mainsail downwards towards the boom, or forward towards the mast. Where the main sail is a wing sail, which is a solid sail that is not able to be reefed, it may be difficult to decrease the area of the sail. One way of achieving a different sail area is by changing the wing sail for a wing sail of a different area, this requires stepping and un-stepping wing sails.

French patent publication <CIT> discloses a sail incorporating the features of the preamble of claim <NUM>.

It is an object of the present invention to provide a nestable wing sail that overcomes or at least partially ameliorates some of the abovementioned disadvantages or which at least provides the public with a useful choice.

The present invention relates to a wing sail for a yacht according to claim <NUM>.

In a further embodiment, the primary section comprises a cavity defined by the sides, that can receive the movable section.

In a further embodiment, the primary section and movable section comprise sail area that make up the sail area of the wing sail.

In a further embodiment, the sail comprises at least two sail sections, a primary section forming an aerofoil wing shape having a cavity intermediate port and starboard face sides which converge to form at the primary section a leech, and at least one movable section moveable between a first condition where the movable section is enveloped or partially enveloped in the cavity or otherwise stored at the leech, and a second condition where at least a portion of the movable section extends from the leech out of the cavity intermediate the primary section leech, where in the second condition the movable section adds to the sail area of the sail.

In one embodiment, the sides comprise aerofoil surfaces.

In one embodiment, the movable section is nested or partially nested within the primary section.

The below embodiments may relate to any of the above statements of invention.

In one embodiment, in the first condition the movable section is fully nested within the primary section so that the leech of the primary section forms the leech of the sail.

In one embodiment, in the second condition the aft edge of the movable section forms at least part of the leech of the sail.

In one embodiment, the movable section translates with respect to the primary section to move between the first and second condition.

In one embodiment, the movable section rotates with respect to the primary section to move between the first and second condition.

In one embodiment, the movable section rotates rotate about a pivot point near the head of the sail.

In one embodiment, the movable section rotate about a pivot point near the foot of the sail.

In one embodiment, the primary section comprises flexible regions at its leech that is configured to flex to allow the movable section to pass intermediate the sides of the primary section through the primary section leech.

In one embodiment, the movable section is a soft sail.

In one embodiment, the movable section is an aerofoil wing sail.

In one embodiment, the aft edges of a sail section form a leech when not spread laterally apart by an adjacent sail section.

In one embodiment, the aft edges of a sail section overlap with the adjacent section to form a join comprising a substantially continuous surface between the sections adjacent each other when spread apart by the adjacent sail section.

In one embodiment, the joins bridge adjacent sections so as to form a substantially continuous surface between adjacent sail sections.

In one embodiment, the sail comprises two or more movable sections.

In one embodiment, the sail comprises the movable section and a second movable section.

In one embodiment, the second movable section nests within the movable section, in a similar configuration to how the movable section nests within the primary section.

In one embodiment, at least a portion of the movable section leech is configured to allow at least a portion of the second movable section to pass therethrough.

In one embodiment, each sail section has a sail area greater than the sail section aft of it.

In one embodiment, the sail comprises a mechanism to actuate the movable sections between their first and second conditions.

In one embodiment, the wing sail has an adjustable effective sail area by extending or retracting a nested wing sail section through the leech of a primary wing sail section.

In one embodiment, the nested wing sail section nests within a cavity of the primary wing sail section.

In one embodiment, the area towards and along the leech of the primary wing sail section is flexible to allow the nested wing sail to pass therethrough.

In one embodiment, there are multiple nested wing sail sections within the primary wing sail section configured to extend the effective sail area of the sail.

In one embodiment, the primary wing sail section is attached to a yacht.

In one embodiment, the primary wing sail section comprises a mast.

In a further embodiment, a yacht comprises the sail described above.

In one embodiment, the yacht comprises mechanisms to actuate the moving of the one or more movable sections.

In one embodiment, the yacht extends its effect sail area by moving a moveable section at least partially out of the primary section.

Other embodiments may become apparent from the following description which is given by way of example only and with reference to the accompanying drawings.

The term "comprising" as used in this specification means "consisting at least in part of". When interpreting statements in this specification which include that term, the features, prefaced by that term in each statement, all need to be present but other features can also be present. Related terms such as "comprise" and "comprised" are to be interpreted in the same manner.

The invention will now be described by way of example only and with reference to the drawings in which:.

With reference to the above drawings, in which similar features are generally indicated by similar numerals, a sail according to a first aspect of the invention is generally indicated by the numeral <NUM>.

In one embodiment now described, there is provided a nestable wing sail <NUM> configured to be used on a yacht <NUM>. The yacht having a hull <NUM>, and the wing sail optionally attached to the hull via a mast <NUM>. Alternatively, the mast may be integral with the wing sail. The wing sail is preferably of an aerofoil shape, and is formed from skins that create the sides of the wing sail, and the surfaces to be the effective sail area.

The sail <NUM> comprises a primary, or forward section, from which two or more moveable sections are able nest within. The primary section comprises a cavity <NUM>, for the moveable sections to nest. The moveable sections are able to extend out from the cavity <NUM>, and aft through the leech <NUM>. There may be multiple moveable sections able to nest within the primary section. Moveable sections may be described as first, second and third moveable sections and so forth. The primary section <NUM> (as shown in <FIG>) houses the moveable sections.

Moving of the moveable sections aft from the primary section allows the sail <NUM> to increase its effective sail area. To reduce the sail area, the moveable sections are retracted back into their adjacent and forward sections, from their extended position.

<FIG> shows a primary section <NUM> having a first moveable section <NUM> extending from the primary section <NUM> leech <NUM>. The leech <NUM> is formed from each aft edge <NUM> of each side <NUM> of the primary section <NUM> (as shown in <FIG>).

In the embodiment shown in Figure 1A, the first moveable section <NUM> extends out from the leech <NUM> about a pivot point <NUM> located near the head <NUM> of the primary section <NUM>. As the first moveable section <NUM> extends aft from the primary section <NUM>, the primary section aft edges <NUM> becomes a cover or join <NUM> intermediate the primary section <NUM> and the first moveable section <NUM>. The leech <NUM> of the first moveable section <NUM>, then becomes the leech of the sail <NUM>.

Figure 1B shows the first moveable section <NUM> nested within the primary section <NUM>. The leech <NUM> of the primary section <NUM> is the leech of the sail <NUM>.

The embodiments shown in <FIG> & <FIG> are just one embodiment of an extendable nested wing sail. The embodiment shown in <FIG> & <FIG> shows a rotating moveable section <NUM>. Other embodiments may be used and fall within the scope of invention, such as embodiments shown in <FIG> & <FIG> where a translating moveable section <NUM> is used. In further embodiments, such as in <FIG>, an unfurling moveable section <NUM> is utilised to extend the surface area of a wing sail. This will be described in further detail later.

There may be multiple extending sections that can be nested within the primary section <NUM>. <FIG> show a sail with two moveable sections <NUM> and <NUM>. Again, these moveable sections <NUM>, <NUM> may translate from the primary section <NUM>, or they may rotate about a pivot point from their adjacent forward section, or both may rotate about the primary section (not shown), or they may utilise a combination or translation and rotation.

<FIG> show details of a simplified cross section of the embodiment of <FIG> & <FIG>. It can be seen that the aft edges <NUM> of the leech <NUM> of the primary section <NUM> are able to open up to allow the first moveable section <NUM> to pass therethrough.

<FIG> show a perspective view of the embodiment of <FIG>, and show that the trailing edges <NUM> or leech <NUM> of the primary section <NUM> open up and allow the moveable section <NUM> to pass through.

<FIG> shows an embodiment where the first moveable section or any of the trailing sections are able to trim or rotate with respect to the primary section, and/or their adjacent sections. This allows the wing sail <NUM> to be better configured for the wind / sailing conditions.

<FIG> show a sail <NUM> that has a nested section that is able to be partially extended out from the primary section <NUM>. This allows a graduation of configurations between a fully retracted and a fully extended condition of the sail <NUM>. This partial extension can be used in any of the embodiments as described herein.

<FIG> also show the moveable section <NUM> being able to pivot about a point <NUM> to trim the sail. There may be multiple moveable sections that are able to trim. This trimming configuration may be used in any of the embodiments as described herein.

<FIG> & <FIG> show the retracted and extended configurations of a translating moveable section <NUM>. <FIG> & <FIG> show a translating nested section <NUM> that translates from the trailing edge or leech <NUM> of the primary section <NUM>. An extension mechanism <NUM> and a retraction mechanism <NUM> is used to extend and retract the one or moveable sections.

In the most basic form the extension mechanism <NUM> is a rope or other flexible member, such as wire, in combination with one or more pulleys <NUM> that allows pulling of a rope at one end to extend the first moveable section <NUM> from the primary section <NUM>. As shown in <FIG>, a retraction mechanism <NUM> is a rope attached to the foot <NUM> of the moveable section <NUM>, so the moveable section <NUM> is able to be pulled towards the bow of the boat, to nest inside the primary section <NUM>.

There may be numerous extension and retraction mechanisms configured and designed to allow optimum or desired extension and retraction of the nested sections. An alternative rope and pulley system is shown in <FIG>, where a boom <NUM> is utilised to locate a pulley <NUM> at its distal end. This allows a rope to pull out a moveable section towards the distal end of the boom <NUM>.

There are many other extension and retraction mechanisms that could be utilised with the present invention. Some examples are linear actuators which are, for example, hydraulic or electric powered.

<FIG> show a further embodiment of the invention, wherein the nested section <NUM> is a single "soft" or "2D" sail. The soft moveable section <NUM> is configured to be unfurled about a roller <NUM> to extend it outwards from the leech <NUM>. This is a more simplified design, wherein the leech <NUM> does not need to extend laterally as much to allow the soft moveable section <NUM> to pass therethrough, compared to a wing moveable section.

<FIG> show a further embodiment, where the moveable section <NUM> is configured to slide/translate downwards towards its extended condition as shown in <FIG>. The moveable section <NUM> is configured to slide along tracks <NUM> (not all shown) to move between a retracted and extended condition. This embodiment allows the movable section <NUM> to be gravity assisted towards its extended condition. A simply halyard system attached to the moveable section <NUM> may be used to retract the moveable section <NUM> back into the primary section <NUM>. This is just one embodiment of a tracked system, there may be many different configurations and track patterns appropriate for different sail types, and designs. For example, less steep tracks, tracks that utilise hydraulics to move the moveable sections <NUM> etc..

<FIG> show a further embodiment of the present invention where the aerofoil shape of the moveable section <NUM> fully extends out of the aerofoil shape of the primary section <NUM>. This configuration allows air flow intermediate the leech <NUM> and the luff <NUM> of the moveable section <NUM>. This configuration of a gap seen, often seen intermediate a trim tab and main section is known in existing wing sails. However, this trim tab has not previously been able to be retracted into a forward sail section, or been able have its effective sail area removed from the overall effective sail area.

The moveable section <NUM> seen in <FIG> may be able to pivoted about an axis so as to allow differing wing shapes.

The leech <NUM> may be configured to allow easy entry of the movable section <NUM> back in to the primary section <NUM>. <FIG> shows the upturned edges of the leech <NUM> that allow the movable section <NUM> to start entering into the leech <NUM>. This is required, as in other embodiments where the movable section stays keeps the leech <NUM> open, in the <FIG> embodiment the leech <NUM> is allowed to close back in on itself. And thus, a configurations such as a upturn at each leech edge is utilised to allow the movable section <NUM> to start entering into the leech <NUM>.

The leech opening, for all embodiments, it may be of a variety of configurations. In one embodiment, the wing sections may have flexible ribs on each side that are configured to flex outwards so that the aft edge of the wing section, at the leech edge <NUM>, able to laterally open up to allow movable sections <NUM> to enter and exit. Flexible ribs (or battens) are well-known in the sailing industry.

The leech <NUM> of a section that is able to laterally open up has aft edges <NUM> as shown in <FIG>.

In some embodiments the aft edges <NUM> are substantially stiff so that they are able to be actuated laterally outwards (independent of the respective moveable section) to allow a movable section to pass therethrough. This is an alternative to the movable section itself opening up the aft edges <NUM>/leech <NUM> as it passes through. However, in most embodiments, the aft edges that form the leech of a respective section are substantially resilient and flexible so that they follow the outer surface of the respective movable section.

Preferably the aft edges <NUM> are able to form a join <NUM> as described previously. This join may include or have an integral flexible member that is compliant with the angles between two adjacent sections. The join ideally creates a smooth transition between the sail sections.

The aft edges <NUM> may in some embodiments be biased open (i.e. laterally spread apart), with actuation to close the aft edges <NUM> to form a leech <NUM>, in behind the moveable section once it is fully nested within the section that houses it. However, more likely, is that the aft edges <NUM> are biased closed, and forced to be spread laterally apart by moveable section passing through.

Where the leech <NUM> and aft edges <NUM> and other features of the primary section are described, it is incorporated in the present invention that the moveable sections that have further nested moveable sections within them, may include the same designs, features and configurations of the primary section.

Claim 1:
A wing sail (<NUM>) for a yacht (<NUM>), the wing sail (<NUM>) comprising at least two sail sections,
a. a primary section (<NUM>) attached, integral with, or comprising a mast (<NUM>), and comprising two skins forming at least part of an aerofoil surface, the primary section (<NUM>) further comprising a leech (<NUM>) at aft edges (<NUM>) of and where the two skins converge, and
b. a movable section (<NUM>) configured to move between a first condition where the movable section (<NUM>) is nested or partially nested within or at the leech (<NUM>) of the primary section (<NUM>), and a second condition where the movable section (<NUM>) extends at least in part from at least part of the leech (<NUM>) from intermediate the two skins, characterized in that
c. the sail comprises a second movable section (<NUM>), wherein the second movable section (<NUM>) nests within the movable section (<NUM>) in a similar configuration to how the movable section (<NUM>) nests within the primary section (<NUM>).