GB2398283A

GB2398283A - Sail with swallow tailed trailing edge

Info

Publication number: GB2398283A
Application number: GB0303528A
Authority: GB
Inventors: William Francis Pentecost
Original assignee: Individual
Current assignee: Individual
Priority date: 2003-02-15
Filing date: 2003-02-15
Publication date: 2004-08-18
Anticipated expiration: 2023-02-15
Also published as: GB2398283B; GB0303528D0

Abstract

A sail is provided with a leading edge 4, a trailing edge 7 which is longer that the leading edge, an upper edge 5 and a lower edge 6, in the general configuration of a Polynesian crab-claw sail. The upper and lower edges are of substantially similar length and are longer than the trailing edge. The trailing edge is formed into a swallow tail 25 and the upper and lower edges of the sail are profiled (Fig 2), with the cross-section of the sail increasing in thickness towards said upper and lower edges, such that in use wind vortices (34, Fig 2) are created along the upper and lower edges of the sail. The profiled upper and lower edges of the sail may be generally triangular in cross-section, with the outermost surface (30, Fig 2) of the triangular section being convex.

Description

Kiwi Claw This invention relates to sail systems for watercraft, land and

ice yachts, power generators, and other systems working on, or worked on by fluids, liquid or gas.

Sails are well known for harnessing the wind to produce power. Polynesian or crab-claw sails were proven to be most effective by Tony Marchaj in his research paper, The Potential Driving force of Various Rig Types Used For Fishing Vessels," and presented in 1987 at Southampton University.

Controlled tests showed the Arab Claw" sail to be superior in power to all other systems tested. The extra power came from the vortex effect produced when air passed across the yard and boom and along the sail, producing high speed circular air flow, and hence reduced pressure on the leeward side of the sail. Practical tests proved the system to be potentially easy, light, balanced and forgiving to handle with less tipping of the craft. On most points of the wind the crab claw proved to be up to 30% more powerful than the popular Bermudan sail-system. In addition the crab claw requires a shorter mast so reducing weight aloft. The centre of effort is moved lower and toward the centre of the craft.

Although the effectiveness of this sail system has been proven in the wind tunnel and thousands of years of practical use, it has not found a wider application in modern dinghy and yacht sails as the control systems have been considered to be too clumsy or not practical with no changes in the original crab claw sails to improve the reliability and strength of the vortex effects. At present the yard and boom tend to supported on one side of the mast so that the aspect of the sail is different on different tacks. Yard and boom cross- sections tend to be round with no shaping to help the forming and sustaining of the vortex. The nose or foremost part of the sail tends to be a point or straight section of sail with no real aerodynamic control or variation. There is no reefing system. The after or trailing edge or leech of the sail tends to be a simple curve from the after end of the yard to the after end of the boom with no possibility for complex shape changes to enhance and sustain the vortex.

There is no baton system. There is also no tensioning or reefing system in the sail itself.

According to the present invention there is provided a sail system with adapts the crab-claw concept to modern materials and possibilities with the sail trailing edge and leading edge comprising complex curves, allows the nose" and trailing edge shape of the sail to a supported, the leading edge and trailing edge more defined to help the vortex effect with yard and boom profiled to improve the vortex effect, yard, boom and mast sleeve adapted so the sail presents the same on both tacks yet still pivot up and down, a baton system, a reefing / sail shaping system and a thus giving a more easily controlled and more effective sail.

The boom, yard and sail are shaped so as to encourage and improve airflow in a circular motion leading to a vortex on the leeward side of the sail. The mast is able to pass through the boom, yard and mast sleeve so that the same aspect is presented on both tacks or in simpler versions there can be a recess or slot in the configuration of the yard and boom so that the centre line of the yard and boom is closer to the mast. The mast sleeve is typically a loose fit on the mast, and may be of varying width along its length so that the ends of the rig can swing higher or lower. With tensioners or porous material at the nose and trailing edge the working surface of the sail can be held in a shape to enhance and sustain vortex effects while keeping the desired profile of a substantially flat sail. The reefing system that draws the upper and lower portions of the sail toward each other, can also be used to flatten the sail near the boom and yard and enhance the double curve on the leeward side of the sail while increasing flow at the centre of the trailing edge to sustain and improve the vortices. The reefing and tensioning system may also be used to put curvature into the yard and boom. Whereas the present system of round yards and booms gives unpredictable and unreliable vortices the generally triangular cross-sectioned vortex profile explained herein gives a sharper draw over the base of the vortex profile while the concave shape of the sides of the vortex profile encourage the circular movement of air leading to vortices along the yard and boom on the lee side of the sail. Where ducting is used with or without a porous membrane, air can be directed to promote circular vortex movement at the fore end of the rig, along the sail and at the trailing edge.

Ducting may also direct air into the longitudinal sleeve to give the sleeve shape and air supply to porous membrane along the sleeve. At the trailing edge the ducts may take the form of baffles that may or may not support a mini-sail that is positioned and shaped to direct fluid movement into the vortex. Such mini- sails, fore or aft, may be rigged to set out of line with the main sail so as to promote the fore or aft mini-sail's effectiveness. The porous membranes are also designed to enhance the circular movement of air as well as tension and support the shape of the sail. The porous membrane can be a porous cloth-like material or as open as a mesh or net and even just lines joining the parts of the sail. The porous membrane may also be semi-elastic in composition to aid tensioning and flattening of the sail. Baton sleeves and batons may be incorporated in the sail in a generally fore to aft configuration and may be used to both stiffen and flatten the sail as well as working with the tensioning and reefing system be used to shape the configuration of the sail to enhance the double curve on the leeward side of the sail to help build the vortices. Infill may be used to help shape the boom, yard and central sail sleeve to produce the desired curves along the sail.

The combined effect of these features gives greater yet easier control, enhanced power with improved reliability and power in the vortices, and the same aspect whichever side of the boat the wind is blowing from. The variations in proportions of the various parts of the sail can move the centre of effort up and down and forward and aft and increase or decrease the working area of the sail. A hinged spar and boom with a foresail that remains at one with the mainsail give further options. Where a separate foresail is used and particularly if it is a Kiwi Claw, the spar and double bowsprit option gives great ability to set the foresail across the craft to take advantage of the sails particular sailing characteristics. The ability to set foresails across the boat and set the tack to windward gives gennacker type sail the same windward setting advantages experienced with jibs on a swing wing rig. In addition foresails and gennackers can be set further aback than with a single bowsprit to swing the bow of the boat around when tacking which is particularly advantageous with multihulls and tunnel hulled craft. These features may benefit other sail systems in particular lateen, sprit, gunter and lugsail and other sail types as well as other systems acted on, or acting upon, fluids and gases.

According to the present invention there is provided a sail system with a generally triangular shaped yard and boom and shaped fore or leading section and shaped aft or trailing sections of the sail supported by a porous membrane with yard and boom in and a mast sleeve formed so that the mast can run through them and the sail system can tilt by raising or lowering the nose of the sail.

Preferably the yard and boom will be generally triangular in cross section with a convex base and concave sides with the apex attached to the sail.

Optionally the yard and boom may be a UT" section.

Optionally the yard and boom may be an oval section Optionally the yard and boom may be a ladder construction.

Optionally the yard and boom may vary in width along their length.

Optionally the convex base of the vortex cross section may be attached to a conventional round yard or spar.

Optionally there is an infill in the general shape of a triangle.

Optionally the infill clips over the yard or boom.

Preferably the infill is a foam material.

Preferably the foam material is closed cell to aid buoyancy.

Optionally one or more members join the two sides of the vortex crosssection.

Preferably there is a mast sleeve.

Optionally the mast sleeve and boom and yard vary in width along their length.

Preferably the mast sleeve is widest at the boom end.

Optionally the mast sleeve is comprised of one or more flaps.

Preferably the foremost part of the sail is shaped to enhance the vortex effect.

Optionally the foremost part of the sail has a convex curve from the yard to the boom.

Optionally the foremost part of the sail has a swallow-tail shape.

Optionally there is provided a porous membrane to help control the shape of the nose or foremost part of the sail.

Optionally there is provided ducts in the foremost part of the sail to direct the air in a circular motion.

Optionally the porous membrane extends along the length of the sail.

Preferably there is provided a "swallow-tail" shape in the trailing edge of the sail.

Preferably the swallow-tail shape is supported by a porous membrane.

Optionally the swallow-tail may have convex and concave curves.

Optionally the swallow-tail may extend from the after end of the yard and boom over 50% of the distance to the mast.

Optionally porous membrane may be made from a porous cloth or sheeting.

Optionally the porous membrane may be a mesh.

Optionally the porous membrane may be made of netting.

Optionally the porosity is achieved through a row or rows of holes in the sail.

Optionally there may be a variety of porous membrane types in one sail or rig.

Optionally the porous membrane may consist of lines linking the upper and lower parts of the sail.

Optionally the lines may be able to drawn to tension them and the sail Optionally the lines may run through anchor points and be able to be drawn together to tension and reef the sail.

Optionally there are separate fore and aft tensioning and reefing lines.

Optionally the there may be a plurality of rows of anchor points along the sail.

Optionally the row or plurality of rows of anchor points are located on both sides of the sail.

Optionally there may be elastic connections between the anchor points to provide continuous tensioning on the sail.

Preferably there is provided a mast slot in the yard and boom.

Optionally the mast slot is elongated.

Optionally the mast slot is substantially covered by the material of the yard and boom sleeve to leave just a slit for the mast to go through.

Optionally the yard and boom may be able to be split into two or more lengths.

Preferably one of the splits in the length of the yard or boom may be at the mast.

Optionally the split in the length of the yard or boom may comprise the mast slot.

The yard and boom may be hinged laterally.

Optionally the foremost part of the yard, boom and sail may hinge at the mast.

Preferably flaps in the foresail extend past the mast so there is still in effect one continuous sail.

Preferably the yard, boom and sail hinge laterally forward of the mast.

Preferably the yard, boom and sail hinge laterally between the nose of the sail and the mast between ten and fifteen degrees in either direction from the line of the yard and boom.

Typically there will be a mast extension when a foresail is used.

Optionally that extension will be a forward mounted spar.

Optionally the spar will be able to swing out from the mast at its upper point so it can be let away from the vertical or brought back into line with the mast.

Typically the tack of the foresail will be attached to a bowsprit.

Preferably there will be two bowsprits with the tack of the sail able to run between them.

Optionally the vortex profile and is used on the blades or fins of fluid movement equipment.

Optionally the vortex profile is used on the leading edge of propeller blades.

Optionally the vortex profile is used on the leading edge of fan blades.

Typically the vortex profile will be used with a swallow-tail trailing edge.

Typically the vortex profile will be built into the blades and fins.

Optionally the vortex profile will be a stick on slotted onto the blade or fin.

Typically the vortex profile will vary in width along its length.

Optionally the swallow-tail will form a complex curve with convex and concave shape in the trailing edge.

Optionally there may be a series of blades or fins with vortex profiles and swallow-tails mounted in sets along an axis or hub.

Optionally there may be a series of blades or fins with vortex profiles and swallow-tails mounted along an axis or hub in staggered formation.

Optionally the vortex profiles and swallow-tails may be mounted on a pump.

Typically the vortex profiles and swallow-tails may be mounted in a device acting on or acted upon by a fluid with the blades reaching tight to the housing or ducting.

Optionally the vortex profiles and swallow-tails may be mounted on a device acting upon or acted upon a fluid with a gap over three millimetres between the outer edge of the vortex profile and the housing or dusting.

Optionally the device acting upon a liquid fluid will be a pump.

Optionally the device acting upon a gaseous fluid will be a fan.

Optionally the device acting upon a fluid will be a propeller.

Optionally the device acting upon or acted upon a fluid will be a turbine.

Typically the device acted upon by a liquid will be a power generator.

A specific embodiment of the invention will now be described by way of example with reference to the accompanying drawing in which: Figure 1 is a side view of a Kiwi Claw sail rig.

Figure 2 is a cross section of a vortex profiled yard and boom connected by a sail with an illustration of the air flow and vortices.

Figure 3 shows a cross section of a T section yard and boom connected by a sail.

Figure 4 is a view of a cross section of an oval shaped yard and boom with sleeves connected by a sail.

Figure 5 is a view from above of a yard and below of a boom showing the mast slot.

Figure 6 shows a side view of a kiwi claw sail and rig with porous sections.

Figure 7 is an illustration of the forward or nose piece of the sail depicted in Fig. 6 Figure 8 is a side view of the kiwi claw rig with anchor points and tensioning and reefing lines and sail batons.

Figure 9 shows a cross section of a Ladder" type boom or yard with connecting member and binding member.

Figure 10 is a view from above of a parallel ladder type yard or boom slotted over a mast.

Figure 11 is a view from above of a ladder type boom or yard of varying width along it's length positioned over a mast.

Figure 12 illustrates across section of ladder yard and boom inside sleeves that are connected by a sail in a reefed position.

Figure 13 is a cross section of a ladder yard or boom inside a sleeve with a joining member giving shape to the base of the vortex profile.

Figure 14 illustrates a cross section of a vortex profile formed around a typical round shaped yard or boom with a joining member tensioned between the sides of the sleeve to give them the desired concave shape.

Figure 15 is an illustration of a cross section of a kiwi claw rig and vortices with sail in a reefed position and the mid part of the sail bulging to leeward.

Figure 16 is a view from above of a yard or boom with built on width to make the mast slot.

Figure 17 is a split version of Fig.16 Figure 18 is an illustration of a cross section of a sail where one section is joined to the other about the mast by means of flaps.

Figure 19 is similar to Fig.18 but involves only one flap.

Figure 20 is an illustration of a sail divided into sections which can be separated from the rest of the sail for reefing.

Figure 21 shows a cross section of vortex profiles mounted on fins or blades attached to a hub or axis.

Figure 22 shows a cross section of a vortex profile insert or stick on.

Figure 23 is a side view of vortex profiles on blades or fins mounted on a hub.

Figure 24 is similar to figure 22 but with a blade or fin attached.

Figure 25 illustrates a cross section of vortex profile and kiwi claw trailing edge blades or fins mounted on a hub inside a housing or dusting.

Figure 26 shows a view from above of a length of vortex profile of increasing width.

Figure 27 shows as Fig. 26 but with varying width.

Figure 28 shows a cross section of a vortex profile with built in mounting slot.

Figure 29 is much as Fig 27 but with a built in curve suitable for use with blades or fins.

Figure 30 shows a side view of three banks of blades or fins mounted in series on a hub and within a housing.

Figure 31 shows a side view of a hub or pod mounted with banks of blades or fins with vortex profiles and kiwi claw trailing edges.

Figure 32 is a side view of a portion of a vortex profile and kiwi claw trailing edge with a convex / concave configuration.

Figure 33 is as above but with a concave / convex configuration.

Figure 34 shows a cross section of a vortex profile with ladder yard or boom, pocket side tie member and extended base shaper.

Figure 35 is a cross section of a vortex profile where the shape is achieved by an infill slotting over the yard or boom makes a convex base and a pocket side tie member makes the sides concave.

Figure 36 is a view from above of a yard or boom with a side slot for the mast and tapering infill shapers.

Figure 37 shows a side view of a craft with a mast pocket widening toward the boom with the boom in the down" position.

Figure 38 shows a side view of a craft as above with the boom in the up" position and the mast at the forward side of the mast sleeve at the boom end.

Figure 39 is a cross section of a vortex profile with a base shaper mounted on a yard or boom and two members connecting and shaping the sleeve sides.

Figure 40 is a view from above of a yard or boom where the sleeve is tatted with only a slit for the mast to slot through.

Figure 41 is a view from above of a yard or boom where the forepart of both are hinged about the mast, but flaps join the fore and aft part of the sail.

Figure 42 is similar to 41 but the hinged part is forward of the mast.

Figure 43 is a side view of a craft with foresail rigged to a forward mounted spar and a bowsprit.

Figure 44 is a view from above of Figure 43 illustrating a double bowsprit with foresail with tack set to port and the head to starboard of the craft.

Figure 45 is a cross section of a yard or boom with infill additions on both sides encompassed by a sleeve.

Referring to the drawings the numbers represent the following 1 Sail 2 Mast 3 Mast Sleeve 4 Nose of Sail Yard 6 Boom 7 Trailing-Edge 8 Tensioners 9 Mast Slot 10 Porous Membrane 11 Yard or Boom Sleeve 12 Ducts 13 Reefing Points 14 Reefing Line Yard or Boom Longitudinal Member 16 Yard or Boom Spacing Member 17 Assembly Member 18 Joining Profile Member 19 Intel Flap 21 Yard or Boom Joining Member 22 Blade, Fin or Sail 23 Vortex profile 24 Hub 25 Kiwi Claw or Swallow-tail trailing shape 26 Housing 27 Shaped Insert 28 Stick-on-Profile 29 Mounting Slot 30 Base of Vortex Profile 31 Side of Vortex Profile 32 Leeward Side 33 Windward Side 34 Vortex Direction of Gas or Liquid Flow 36 Base Extender for Vortex Profile 37 Joining member for Yard or Boom Sleeve Sides 38 Mast Slit 39 Hinge Mechanism 40 Bow Sprit 41Spar 42 Foresail 43 Hull 44 Control Member 45 Bow 46 Sail Baton 47 Longitudinal Sleeve Duct 48 Hooped opening to longitudinal sleeve duct 49 Forward Protruding Fin or Blade Base 50 Tack of Sail 51 Flow baffles 52 Mini-Sail 53 Convex Curve Referring firstly to Figure 1, a sail (1) is generally shown in side view, rigged on a mast (2) and supported between a yard (5) and a boom (6) set both fore and aft of the mast (2). The mast (2) is passed through a mast sleeve (3) which may be arranged substantially loosely about the mast (2) and generally parallel to it. In this illustration the mast sleeve (3) is relatively narrow at the top or yard (5) and widens toward the base or boom (6) end to allow for vertical movement of the fore and aft sections of the sail as illustrated in Figures 37 and 38. The "nose", luff, or leading edge and generally forward section of the sail (1) is shaped in a swallow tail shape (25) which is supported by a tensioner (8). The trailing edge or leech (7) of the sail (1) is in a swallow tail shape (25) and supported in the shape by a porous membrane (10). It can be seen that the sail (1) increases in height from the forward section or nose (4) to the aft section or leech (7) The swallow tail shapes (25) in the nose (4) and trailing edge (7) are designed to help build and sustain the vortices which are significant in producing the extra power attributed to the crab claw sail system. The swallow tails (25) and other leading and trailing edge shapes would just flap in the wind unless held in place by the porous membrane (10) or tensioners (8).

Figure 2 illustrates the same sail (1) and yard (5) and boom (6) as shown in Figure 1 viewed in cross section. The sail (1) is generally flat as possible while tensioned between the "vortex profiles" (23) of the yard (5) and the boom (6). The vortices (34) form along the yard (5) and boom (6) as air flow (35) from the windward side (33) passes across the base (30) of the vortex profile (23) and reacts with air flow (35)on the lee side of the sail (32) which passes along the sail (1) and is aided in the circular mixing of the two air movements to produce the vortices (34) by the concave sides (31) of the vortex profile (23) Figure 3 illustrates a cross section of a simple construction to gain the effects of Figure 2 wherein the boom (6) and the yard (5) are a UT" section forming a simple aid to vortex effect in which the top of the UT a forms the base of the triangle and the stem is connected to the sail "1". Such a profile would be more effective within a sleeve as in the Figure 4 sleeve (31).

Figure 4 is a cross section illustrating an oval shaped yard (5) and boom (6) wherein the oval shapes the convex base (30) of the vortex profile and the yard or boom sleeve (11) form the side of the vortex profile (31) which join the sail (1) Figure 5 is a view from above on a yard (5) or below on a boom (6) of the base of a vortex profile (30) with an slot (9) for the mast (2) to slip through. The slot (9) is elongated so the sail can swing up and down as illustrated in Figures 37 and 38.

Turning to Figure 6 a side view of a sail (1) with porous membranes (10) supporting the swallow-tail (25) at the trailing edge and nose (4) of the sail and also forming a sleeve or duct (47) along the sail. A duct (12) directs air into the longitudinal sleeve (47) which is keep open at the nose (4) by a supporting arrangement or hoop (48). Such a longitudinal sleeve duct (47) helps shape the sail (1) as illustrated in Figure 14 when used with or without infill (19).

Figure 7 is a closer view of a sail (1) nose (4) where the triangular nature of the vortex profile (23) in the boom (6) and yard (5) are illustrated with base (30) and sides (31) more visible. The ducting (12) is here arranged to direct air across the sail (1) on the leeward side, rather than along it. Such a cross flow is designed to encourage the circular movement of air leading to a vortex.

In the side view of the sail (1) we see in Figure 8 the rows of reefing points (13) a long the sail (1) joined by reefing lines or tensioners (14) which allow the sail(1) to be flattened and when the reefing lines are tightened further while the yard (5) is lowered or the boom (6) is raised the sail (1) may be reefed as illustrated in the cross sections shown in Figures 12 and 15. There will be optionally reefing points (13) and reefing lines (14) on both sides of the sail as the bulge to leeward of the reefed sail may aid vortex formation. Figure 8 also includes a Minisail (52) at the nose (4) which generally but not necessarily is rigged between the yard (5) and boom (6) and follows the outline of the swallowtail. In addition there is illustrated longitudinal batons (46) which in this case follow close to the rows of reefing points (13) and also generally mid way between the yard (5) and boom (6) Because of the mast sleeve (3) and the mast (2) the batons may optionally be half length and fed into the baton sleeves from the each end of the sail(1).

Figure 9 is a cross section of one general type of ladder type boom or yard in which the longitudinal members (15) are spaced by a spacing member (16) which may be the same length along the yard or boom as in Figure 10 or of varying length as in figure 11. The parts are held together by an assembly member (17).

Figures 10 and 11 are views from above of yards (5) or booms (6) with Figure10 being the same width along its length while Figure 11 varies in width.

Both have a mast (2) passing through them. Cross sections of ladder type yard (5) and boom (6) are also illustrated as part of Figures 12 and 13 where they make up the width of the base (30) of the vortex profile.

In Figure 12 the ladder type boom (6) and yard (5) are shown in cross section with the longitudinal members (15) joined by the spacing members (16). The sleeve (11) forms the base of the vortex profile (30) while the sides of the sleeve (11) form the sides of the vortex profile(31). The sail(1) is reefed with the reefing line (14) drawing the reefing points (13) together to reducing the effective working area of the sail and making a bulge in the sail (1) to the leeward side (32). The sail batons (46) both stiffen the sail and make for cleaner lines at reefing points.

Figure 13 is a cross section of a vortex profile with a ladder construction (15,16) with a shaped joining profile (18) harming the base (30) and the mast sleeve (11) forming the sides of the vortex profile (31). To gain the desired concave section of the vortex profile sides (31) the sleeve sides (11) are joined by one or more joining members (37) which would typically be a width of tape sewn along the sleeve sides (11).

Figure 14 is also a cross section with a standard rounded yard (5) or boom (6) within an infill (19) which provides the vortex profile (23). Where the infill is a closed cell foam it will provide buoyancy and protect heads from bangs from the boom (6). The sail (1) has a longitudinal sleeve (47) which is shaped by an infill (19) which again may be of closed cell foam or other materials and may or may not be used with sleeve joining members to provide a diamond shaped section with concave sides. Such an arrangement may run along the sail generally but not necessarily equidistant from yard (5) and boom (6).

Figure 15 is a similar construct to Figure 12 but includes an indication of airflow and vortex build up. The air flow is from the windward side (33) across the base of the vortex profiles (30) drawing air which has been flowing along the sail (1) on the leeward side (32) and turning back in toward the sail and then repeating along the sail until the circular motion increases in speed and spiral effect of the fluid until it is a fast vortex (34) with a reduced pressure area. Where the reefing line (14) has drawn the sail (1) the air flow on the windward side (33) pushed the loose sail material (1) to leeward (32) where it makes a bulge which contributing to a shape which promotes the circular air movement toward a strong and continuous vortex (34).

In Figure 16 we see a yard (5) or boom (6) from above where the fore and aft sections are joined by members (21) in such a way as to form a mast slot (9). In Figure 17 a similar presentation shows the fore and aft sections of the

yard (5) and boom (6) where the joining members (21) can be separated and joined at the mast (2).

Figure 18 shows a sail(1) cross section from above which is designed to go with the construction in Figure 17 in which forward and aft portions separate but may be joined at the mast (2). To keep a continuous surface on the sail (1) the two sections are joined by flaps (20) which will typically be fixed to the fore section and wrap over the mast(2) area to join the aft section.

Figure 19 is largely similar to Figure 18 with the exception that the sail is unbroken on one side and incorporates a flap (20) on the other to take a continuous surface around the mast back to the sail (1) again.

Figure 20 is a side view of a sail (1) in which various sections or flaps (20) may be detached or partially detached as a reefing system.

Turning to Figure 21 we see a cross section of a device where fins or blades (22) with vortex profiles (23) are mounted on a hub (24). The pressure side of the fins or blades (22) will typically but not necessarily be a concave or multi- concave section. Such a hub (24) may a multiplicity of blades or fins (22) mounted with vortex profiles as for example seen in Figures 21, 23, 30 and 31 mounted in various patterns.

Such blades and fins (22) may tend to trail Mown stream" as it were, to enhance the vortex effect as in Figure 23.

In Figure 22 we see the basic vortex profile (23) in cross section as an insert (27).

Figure 23 is just one possible representation of a side view of Figure 21 in which the hub (24) is a pod upon which are mounted fins (22) with swallow tail trailing edges (25) and vortex profiles (23) on their outer edges following the curve of the blade (22) and varying in width as illustrated in Figures 26, 27, and 28. In addition to the outer swallow tail shape (25) there is provided a forward protruding, concave section base (49) for the blades or fins (22). The Base (49) may be shaped in cross section and extended aft in a swallow-tail so as to produce an inner" vortex from the rear of the pod or hub (24).

Figure 24 is a cross section of the fins or blades (22) in Figure 23 showing the double concave shape on the blade as each concave section and swallow tail work on, or are worked on, by the fluid and produce a multi vortex.

Turning to Figure 25 there is illustrated a cross section of a housing (26) within which are blades (22) with swallow tail trailing edges (25) and vortex profiles (23) mounted on a hub (24). This would be a type of cross section seen in pumps, fans, turbines, water jets, water and air generators and propellers.

There may be a multiplicity of blades (22) in a variety of settings and proportions.

The base of the vortex profiles (23) may vary in shape as illustrated in views from above of vortex profiles in Figures 26, 27 and 29.

Figure 28 is a cross section of a vortex profile, in which there is a mounting slot build in.

Further in Figure 30 there is a side view of a hub (24) mounted by a series of blades or fins (22) in three in line groupings within a housing (26), There may be a multiplicity of blades within each grouping with a multiplicity of configurations.

Figure 31 is a side view of a pod or hub (22) with double swallow tail (25) and concave fins or blades (22) with vortex profiles (23) along the outer edges, mounted in staggered formation.

Figures 32 and 33 are side views of the tips of blades (22) with vortex profiles (23) with different arrangements of convex and concave curves on the trailing edges. Different fluids and speeds make different trailing edges appropriate.

Figure 34 is a cross section of a vortex profile with a ladder type (15, 16) boom (6) or yard (5) with sleeve sides (31) controlled by a joining member (37) with an extended vortex profile base (36) which may be aproppriate in some cases.

Figure 35 gives another option where infill (19) provides a convex shape and width in a vortex profile base (30) while mounted on a round boom (6) or yard (5), while a joining member (37) gives the sleeve sides (31) the desired concave shape. There are many construction methods possible to achieve the desired shapes.

Figure 36 is a view from above of a base (30) of a yard (5) or boom (6) such as in, but not necessarily, the construction in Figures 35, 39, 14 and 45. There is provided a recess or mast slot (9) in the infill (19) to help the sail to present the same on both tacks. In this instance the infill tapers from the centre to the ends of the yard (5) or boom (6).

The side view of a craft with sail and rig in Figure 37 shows a sail (1) with a mast sleeve (3) mounted over a mast (2) with the after part of the sail in a lowered position and the aft part of the base of the sail sleeve (3) resting against the mast (2). Figure 38 is the same craft with the aft part of the sail it the raised position and the fore part of the base of the mast sleeve (3) resting against the mast (2). By shaping the mast sleeve (3) thus the over the mast rigging with elongated slots in the yard (5) and boom(6) still preserves a measure of flexibility not found in a tight sleeve system or one which does not have extra width at top or bottom of the sleeve.

Figure 39 Is a cross section of a vortex profile where there is an add on profile (36) to form the base of the profile(30) and double joining members (37) to shape the vortex profile in the sides of the sleeve (31). Again this is just another variation for achieving the vortex profile.

Figure 40 is a view from above of the base (30) of a vortex profile where just a slit (38) is provided for the mast so that there is as little disturbance of air flow as possible.

Figure 41 and 42 show variations of a view from above of a of a yard (5) or boom (6) which hinge (39) laterally forward of the mast (2) with flaps (20) providing continuity of surface of the sail at the mast (2) in Figure 41. Such hinging of the forward part of the rig allows it to be turned to windward. This feature can allow the craft to sail closer into the wind and provide more forward power.

In Figure 43 a side view of a craft (43) with kiwi claw main sail (1) and one of many possible arrangements for a foresail(42). In this case the foresail head is attached to a forward hinging spar (41) mounted on the mast (2). The tack (50) of the foresail (42) is attached to a bowsprit (40). The mainsail (1) has a swallow tail trailing edge with a mini-sail (52) and ducts or baffles (51) directing air flow across the lee of the mainsail (1) to enhance the vortex effect.

Figure 44 is a view from above of the arrangement in Figure 43 where there are two bowsprits (40) with a joining control member (44) which allows the tack (50) of the foresail (42) to be moved across the craft. Combined with a spar (41) which is mounted on the mast (2) in a forwards position to which the head of the foresail (42) is mounted, a foresail can be mounted almost transversely across the craft. This means the tack (50) can be set far out to windward and the head and trailing edge or the foresail (42) can be set out to the leeward side when the spare top is allowed to fall away from the mast. When going about the foresail can be set on the new tack as much as 30 degrees earlier than on with a single bowsprit and so the bow is brought round much more quickly and easily. The latter feature is good to have on all sailing craft, but is particularly useful on multihulls and tunnel hulls.

The final illustration is Figure 45 on page 3 of the drawings. This is a cross section of a simple construction of a boom (6) or yard (5) in which the infix (19)is just simple triangular shaped infill attached to each side of a round spar (5,6) The sleeve (11) then makes up the desired vortex profile.

Individually or combined the features described help create and sustain a more powerful vortex and a more simply controlled rig.

Further modifications and improvements may be incorporated without departing from the scope of the invention herein intended.

Claims

Claims 1 A fin, blade, wing, winglet or sail acting upon or acted upon by

a fluid in the general configuration of a Polynesian crab-claw sail, that is to say flaring out from a narrow nose to two points at the trailing edge, which edges are joined by a concave curve in the shape generally known as a swallow-tail in which the upper edge which on a sail would be known as a yard and the bottom edge which would be known as a boom are profiled, that is shaped or shaped and thickened along all or part of their length in such a manner as to encourage and sustain vortices along the said upper and lower edges.
2 A fin, blade, wing, wingiet or sail acting upon or acted upon by a fluid in the general configuration of a Polynesian crab-claw sail, that is to say flaring out from a narrow nose to two points at the trailing edge, which edges are joined by a concave curve in the shape generally known as a swallow-tail in which the upper edge which on a sail would be known as a yard and the bottom edge which would be known as a boom are profiled, that is shaped or shaped and thickened along all or part of their length in such a manner as to encourage and sustain vortices along the said upper and lower edges as in Claim 1 in which the profiled section or sections are in the general shape of a triangle.
3 A fin, blade, wing, winglet or sail acting upon or acted upon by a fluid in the general configuration of a Polynesian crab-claw sail, that is to say flaring out from a narrow nose to two points at the trailing edge, which edges are joined by a concave curve in the shape generally known as a swallow-tail in which the upper edge which on a sail would be known as a yard and the bottom edge which would be known as a boom are profiled, that is shaped or shaped and thickened along all or part of their length in such a manner as to encourage and sustain vortices along the said upper and lower edges as claimed in Claim 1 in which the profiled section or sections are in the general shape of a triangle as claimed in Claim 2 in which the base or outermost surface of the triangular section or sections is convex.
4 A fin, blade, wing, winglet or sail as in the previous claims in which the triangular section or sections have a concave cross sections on the sides of the triangle, that is the side or sides running from the base to the main surface of the fin, blade, wing, winglet or sail.
A fin, blade, wing, winglet or sail acting upon or acted upon by a fluid in the general configuration of a Polynesian crab-claw sail, that is to say flaring out from a narrow nose to two points at the trailing edge, which edges are joined by a concave curve in the shape generally known as a swallow-tail in which the upper edge which on a sail would be known as a yard and the bottom edge which would be known as a boom are profiled, that is shaped or shaped and thickened along all or part of their length in such a manner as to encourage and sustain vortices along the said upper and lower edges as in Claim 1 in which the profiled section or sections are in the general shape of a "T" section with the stem of the "T" flowing into the main surface fin, blade, wing, winglet, or sail.
6 A fin, blade, wing, winglet or sail acting upon or acted upon by a fluid in the general configuration of a Polynesian crab-claw sail, that is to say flaring out from a narrow nose to two points at the trailing edge, which edges are joined by a concave curve in the shape generally known as a swallow-tail in which the upper edge which on a sail would be known as a yard and the bottom edge which would be known as a boom are profiled, that is shaped or shaped and thickened along all or part of their length in such a manner as to encourage and sustain vortices along the said upper and lower edges as in Claim 1 in which the profiled section or Iq sections are in the general shape of a "T" section with the stem of the "T" flowing into the main surface fin, blade, wing, winglet, or sail as in Claim 5 in which the top of the An' is curved so that it's outer surface is convex.
7 A fin, blade, wing, winglet or sail acting upon or acted upon by a fluid in the general configuration of a Polynesian crab-claw sail, that is to say flaring out from a narrow nose to two points at the trailing edge, which edges are joined by a concave curve in the shape generally known as a swallow-tail in which the upper edge which on a sail would be known as a yard and the bottom edge which would be known as a boom are profiled, that is shaped or shaped and thickened along all or part of their length in such a manner as to encourage and sustain vortices along the said upper and lower edges as in Claim 1 in which the profiled section or sections are in the general shape of an oval.
8 A fin, blade, wing, winglet or sail as in the previous claims in which the profiles on the yard and boom edges vary in size along their length.
9 A fin, blade, wing, winglet or sail as in the previous claims in which the profiles on the yard and boom edges vary in size along their length by beginning very narrow at the nose of the fin, blade, wing, winglet or sail and widening toward the trailing-edge point or points.
A fin, blade, wing, winglet or sail as in the previous claims in which the profiles on the yard and boom edges are formed by add-on profiles.
11 A fin, blade, wing, winglet or sail as in the previous claims in which the profiles on the yard and boom edges is formed by add-on profiles which forms a convex outer edge or base and concave sides which join the base to the main fin, blade, wing, winglet or sail.
12- A fin, blade, wing, winglet or sail -as in the previous claims in which the profiles on-the yard and boom edges are formed by a ladder construction or a multitude of ladder constructions.
13 A fin, blade, wing, winglet or sail as in the previous claims in which the profiles on the yard and boom edges are formed by a shaping profile.
14 A fin, blade, wing, winglet or sail as in the previous Claims in which a fin, blade, wing, winglet or sail as in the previous Claims in which there is provided a swallow-tail configuration at the nose as well as at the trailing edge.
A fin, blade, wing, winglet or sail as in the previous claims in which the swallowtail configuration or configurations have concave sections.
16 A fin, blade, wing, winglet or sail as in the previous claims in which the swallowtail configuration or configurations have convex sections.
17 A fin, blade, wing, winglet or sail as in the previous claims in which a mini sail or multitude of mini sails or baffles are situated about the kin, blade, wing, winglet or sail in such a manner as do direct fluid flow onto or around the fin, blade, wing, winglet or sail.
18 A fin, blade, wing, winglet or sail as in the previous claims in which there is provided a profile or a multitude of profiles running along the length or part of the length of the crab claw from at or near the nose section to at or near the trailing edge.
19 A sail as in Claims 1 to 17 and 25 in which the profile or multitude of profiles is triangular with projection from just one side of the sail in which the triangular profile or multitude of profiles is achieve by reefing lines compressing the width of the fin, blade, wing, winglet or sail.
A profile or multitude of profiles as in Claims 1 to 13 in which the profile or multitude of profiles are constructed so as to split into pieces and slotted together again.
21 A profile or multitude of profiles as in Claims 1 to 13 in which the profile or multitude of profiles are constructed so as to allow a supporting member or mast to be attached to them.
22 A fin, blade, wing, winglet or sail as in Claims 1 to 17 and Claims 25 to 28 in which a sleeve provided to the fin, blade, wing, or winglet or sail to accommodate the support member or mast.
23 A sleeve as in Claim 29 in which the sleeve effect is achieved with a detachable or semi detachable flap or multitude of flaps.
24 A fin, blade, wing, winglet or sail as in the previous claims that is attached to a hub or axel.
A fin, blade, wing, winglet or sail as in the previous claims or a multitude of such fins, blades, wings and wingless and sails as in the previous claims that are attached to a hub or axel.
26 A fin, blade, wing, winglet or sail as in the previous claims or a portion of such that is attached to a hub or axel where the portion or multitude of portions may be a half of the Polynesian crab claw with the divide running from nose to trailing edge.
27 A fin, blade, wing, winglet or sail as in the previous claims or a portion of such that is attached to a hub or axel where the portion or multitude of portions may be a half of the Polynesian crab claw with the divide running from nose to trailing edge with a blade base joining the half crab claw to the hub or axel.
28 A blade base as in the previous claim in which the blade base protrudes upstream into the fluid flow.
29 A fin, blade, wing, winglet or sail as in the previous claims or a portion of such that is attached to a hub or axel where the portion or multitude of portions with or without a blade base that is attached in series formation to the hub or axel.
A fin, blade, wing, winglet or sail as in the previous claims or a portion of such that is attached to a hub or axel where the portion or multitude of portions with or without a blade base that is attached in staggered formation to the hub or axel.
31 A fin, blade, wing, winglet or sail as in the previous claims or a portion of such that is attached to a hub or axel where the portion or multitude of portions with or without a blade base that is attached on contra rotating hub or axel.
32 A fin, blade, wing, winglet or sail or a portion or multitudes of portions substantially as herein described and illustrated in the accompanying drawings.