This invention relates to sailing apparatus of the type used by windsurfers in which a sail is mounted on a mast and boom assembly and is given shape by means of downhaul and outhaul tension being applied, respectively, at the foot of the mast and the free end of the boom. These kinds of sailing systems typically utilize battens at spaced intervals across the width of the sail to give support and shape to it, particularly if the battens are compressed longitudinally within sleeves or pockets so that the sail assumes a curved shape in cross section.

In sailing systems of this general type which are intended to be manipulated by the hands of the windsurfer it is typical for the size and performance of the sail to be tailored to the size and skill of the windsurfer. A larger sail and consequently a larger mast and boom may be used by a relatively large individual but which would be unsuitable for use by a relatively small individual. A high performance sail would not be suitable for an inexperienced windsurfer because too much power could be generated in relatively high wind speeds, especially in gusty conditions. As a general rule, the smaller the area of the sail the less power it will produce and hence the lower the speed it will enable the windsurfing board to travel at.

A balance, therefore, has to be reached between optimum performance and the size and ability of the windsurfer in order, particularly, to cope with extreme conditions such as sudden gusts of wind or high wind speed. In such conditions it is necessary to spill wind out of the sail in order to retain control. This may be achieved in two ways, the most obvious being by letting the clew end of the sail move away from the body of the windsurfer until control is restored. However, this procedure has the effect of reducing the downward pressure of the mast on the board which then allows the front end of the board to lift. This allows air underneath the board which can upset the trim. Even so, skilled windsurfers are able to select the minimum

movement of the clew end of the sail in order to retain control so as to maximize the speed of the craft across the water

The second method of achieving control of the windsurfing craft in high wind speed or gusty weather conditions is by adjusting the downhaul tension of the sail when it is initially rigged on the mast and boom Because modern windsurfing sails are not simply triangular but have a significant area of additional sail beyond the line running between the mast tip and the clew end, the tightening of the downhaul by increasing amounts has the effect of decreasing the amount of stretch in the leech around the area of the head of the sail to the extent that it becomes loose and rippled if viewed edge-on This allows air to spill out of the leech in this region of the sail in gusty conditions Some sail manufacturers even provide instructions on the amount of downhaul tension to be applied in order to achieve the required performance characteristics The problem, however, with this method is that adjustment is not possible during windsurfing and, more significantly, because this area of the sail remains untensioned and loose in normal conditions it is not providing any power to the mast and is therefore very inefficient, causing instead drag to the windsurfing craft This affects the overall power which may be generated by the sail, particularly at low speed or m light wind conditions, so that it only performs to its maximum efficiency in a relatively narrow range of conditions and speeds

It is an object of the present invention to provide a sailing system for windsurfing and similar craft in which the foregoing disadvantages are alleviated or obviated, which increases the efficiency of the sail but which still allows the user to cope with sudden gusts of wind or continuously strong wind conditions

According to the invention there is provided sailing apparatus comprising a mast, a boom securable at its forward end to the mast, a sail including a luff sleeve for mounting the sail on the mast and attachment means at the clew for releasably

securing it to the trailing end of the boom, CHARACTERIZED IN THAT sail support means cooperable with the mast are provided to support the sail against downhaul tension other than at the head such that, in use, when the sail is mounted on the mast and downhaul tension applied, it is isolated from the head of the sail

With this arrangement the head of the sail, which typically includes battens to support the leech and to give it shape, remains relatively tight at all times even after the sail is rigged on the mast and downhaul tension has been applied, so that the entire surface area of the sail is continuously providing power when in use at low, medium or high speed and in all wind conditions Gusts of wind automatically force the head of the sail to bend the upper mast section sufficient to allow excess air to escape and in the lull immediately following the gust the flexure of the upper mast section restores it to its original position, thus providing extra acceleration for the watercraft than would otherwise be the case with conventional windsurfing sail apparatus

The mast may conveniently be in two separate sections which can be releasably connected together by connector means such as a metal ferrule msertible in or on the upper end of the lower section of mast and including a smaller diameter ferrule connected thereto for receiving the lower end of the upper section of mast to form one continuous mast but each section having distinct performance characteπstics in terms of rigidity and flexibility With such an arrangement the sail attachment means may conveniently be integral with the mast connector means and may compπse a lug incorporating a slot disposed in-line with the mast and including a releasable fastener such as a pin disposed transversely to the slot so that the pm may be inserted through an eyelet at the forward edge of the sail just below the head When the sail is rigged on the mast and the pin is thus secured in place, downhaul tension can be applied to the sail but only between the lower end of the sail and the pin, with the head of the sail being isolated from the downhaul tension

Conveniently, the luff sleeve at the head of the sail is separate to the luff sleeve below and is openable along its length by means of a zip or other releasable form of opening. This permits the easy insertion or even replacement of the upper mast section without having to de-rig the whole of the sail so that replacement upper sections of mast may be used as desired, each having more or less flexibility to suit prevailing wind conditions and/or the requirements of the windsurfer.

The head section of the sail at the luff may be generally straight or alternatively it may be curved to force the upper mast section to adopt a corresponding fixed curvature while the sail is rigged in order to increase aerodynamic efficiency and/or increase tension in the leech.

In an alternative embodiment in accordance with the invention the mast is integrally formed and may, for example, be a conventional windsurfing or other sail craft mast, and means are provided between the luff and the mast to limit downward movement of the luff and hence the sail at the head such that when downhaul tension is applied the free end of the mast around the head is substantially not under tension whereas the remainder is under downhaul tension.

Conveniently, this may be achieved by means of a webbing or similar strap stitched to opposite sides of the luff sleeve at the head and arranged to span each side of the luff sleeve and being provided in a central portion thereof with an eyelet or similar device of internal diameter corresponding to or greater than the external diameter of a mast extension piece or tip inserted into the upper end of the mast, the webbing preventing downward movement of the luff sleeve further than the upper end of the mast such that when downhaul tension is applied the mast extension piece or tip is substantially free of such downhaul tension. Preferably, a socket may be incorporated into the upper end of the mast for receiving the lower end of the mast extension piece and/or to act as a bearing or stop cooperable with the under side of the webbing and/or eyelet secured thereto.

It will, however, be appreciated that other stop members may be used without departing from the spirit or scope of the invention which isolates the downhaul tension from the tip of the mast, or from the mast extension piece as the case may 5 be.

A further advantage of sailing apparatus according to the invention over the known prior art occurs when the boom and sail are "pumped" by the windsurfer alternately pulling and pushing the boom and hence sail in order to gather i o sufficient speed from a stationery or stalled condition. In conventional sails where the leech of the head is normally loose and therefore nor working at all in such circumstances, the action of pumping the sail is made relatively more difficult and prolonged than with the sailing apparatus according to the invention where the entire surface area of the sail is working at all times. In addition, the flexibility of

15 the upper section of the mast as compared to the lower section has been found to increase the effectiveness of pumping the sail so that it is easier and quicker to get up to sailing speed than would otherwise be the case.

The invention will now be described, by way of example only, with reference to o the accompanying drawings in which:

Figure 1 is a side view of sailing apparatus according to the invention,

Figure 2 is a view corresponding to Figure 1 but showing part sectional 5 and part cut out portions of the upper parts of the sailing apparatus,

Figure 3 is a perspective view of mast and sail connector means according to an aspect of the invention, and

Figure 4 is a front view of the sailing apparatus of Figure 1 depicting flexure of the upper section of mast and sail in high wind speed conditions

5 Figure 5 is a perspective view of an alternative mast and sail connector means to that shown in Figure 3

Figure 6 shows an alternative embodiment of the invention in which downhaul tension is isolated from the head of the sail by a different l o method to that shown in Figure 2

In Figure 1 there is shown sailing apparatus comprising a windsurfing sail 1 of generally conventional type rigged on a mast 2 and a boom 3 A downhaul 4 at the foot of the mast 2 provides downhaul tension to the sail and an outhaul 5 tensions 15 the sail 1 between the clew and the free end of the boom 3 Battens 6 received in batten pockets (not shown) support the roach in the sail at the leech 7 and through adjustable turnbuckles 8 at the free ends of the battens 6 they can be compressed varying magnitudes to provide cross sectional curvature to the sail 1 Thus far, the sailing apparatus described is of conventional configuration 0

In accordance with this embodiment of the invention, the upper portion of the sail 1 comprises a head 9 with a curved leach which is stitched onto an openable head luff sleeve 10 independent of a conventional mam luff sleeve 1 1 , each of which sleeves surround respective portions of the mast 2 when in use Between the head 5 luff sleeve 10 and mam luff sleeve 1 1 is disposed mast connector means 12 and sail attachment means 13, each of which are described more fully below with reference to Figure 3

In Figure 2 there is shown part in cross section and part in cut out the sailing 0 apparatus of Figure 1 but in which the head luff sleeve 10 is shown in its open

position, the opening being facilitated by zip fasteners 14a, 14b. The mast 2 is comprised of two sections, a relatively short upper section 2a around which head luff sleeve 10 is releasably secured when the sailing apparatus is in use, and a relatively long mast section 2b surrounded by the main luff sleeve 1 1. The lower mast section 2b is comprised of a tubular composite fibre generally rigid material of frusta-conical shape tapering gradually inwards from bottom to top. The upper mast section 2a comprises a generally short tapered fibre rod of length corresponding to the length of the head luff sleeve 10 but being significantly less rigid and hence more flexible than the lower mast section 2b. The two mast sections 2a, 2b, are joined together by the mast connector means 12 on the upper and lower portions of which extend respective ferrules 15a, 15b of outer diameter corresponding to the inner diameter of the respective end portions of the upper mast section 2a and lower mast section 2b so that when connected together by push fit the mast 2 has a continuously tapering profile but with each section having different rigidity with respect to the other.

Turning now to Figure 3 there is show an enlarged view of the connector means 12 and sail attachment means 13 which, in this example, are integral with each other and are made of a suitably strong metal such as titanium or stainless steel. The mast connector means 12 comprises a central disc 16 of outer diameter corresponding to the diameter of the lower portion of the upper mast section 2a and the upper portion of the lower mast section 2b. The cylindrical metal ferrules 15a, 15b are welded coaxially to respective sides of the disc 16 such that the mast sections 2a, 2b (not shown) may be joined together by push fit. The sail attachment means 13 comprises a slotted lug 17 welded onto the side of disc 16 to allow insertion of the forward edge of the sail just below the head 9 where an eyelet in the sail can be releasibly secured in place by means of a metal pin 18 which extends through respective bores in the slotted lug 17 and is itself releasibly secured thereon by means of a wire clip (not shown).

Turning now to Figure 4 there is shown a front view of the mast 2 and sail 1 depicting flexure of the upper mast section 2a in high wind speed conditions such as during a wind gust, as opposed to its normal position shown in broken outline. It will be seen that the flexure of the upper mast section 2a and the corresponding movement of the head 9 of the sail 1 permit air, shown arrowed, to spill out of the sail in this region. The sail shape and power generated is therefore automatically adjusted by the wind itself. In light to moderate wind conditions little or no flexure of the upper mast section 2a will occur but increasing wind speed will increase the amount of flexure. This will, in turn, increase the amount of air spilled out of the head 9 of the sail 1, so that less power is produced and control is retained by the windsurfer. If the conditions are gusty the lull after each gust allows the upper mast section 2a to spring back to its normal fully upright position and in so doing it pushes the sail back to its normal position, this providing extra acceleration to the craft during the lull. This may be contrasted to conventional circumstances whereby a lull following a gust of wind would simply allow the head of the sail to assume its normally wrinkled and untensioned condition where no power is ^* produced in this area of the sail.

In Figure 5 there is shown an enlarged perspective view of a mast connector means 19 different to the connector means 12 shown with reference to Figure 3. In this embodiment the connector means 19 comprises a tubular member 20 having a closed end 21 and open end 22. Adjacent the open end 22 is a welded-on reinforcing collar 23 to which is also welded sail attachment means 24 comprising a pair of spaced apart ears 25, 26 defining a slot. Through respective bores in the ears 25,26 is a metal pin 27 for retaining a sail (not shown) in place between the two ears 25,26, and a locking ring 28.

In use, the tube 20 is inserted into the inside of the lower mast section 2b, being of a dimension to fit snugly therewithin, and the upper mast section 2a is inserted through the opening 22 in the tube 20 until it abuts the closed end 21, so that in

this embodiment the lower portion of the upper mast section 2a lies within the upper portion of the lower mast section 2b, in contrast to the situation apparent with regard to Figure 3 whereby each mast section is connected end-on-end by being mounted on, respectively, the coaxial metal ferrules 15a, 15b, and being spaced apart by the central disc 16. However, as with the sail attachment means shown in Figure 3, a similar sail attachment means 24 is provided to allow insertion of the forward edge of the sail just below the head 9 where an eyelet in the sail can be releasably secured in place by means of the metal pin 27 which, in turn, is releasably secured in place by the wire clip 28.

In Figure 6 there is shown partly assembled an alternative embodiment of the invention particularly useful for conventional masts where an extension piece or tip may be inserted into the upper end thereof, such extension piece or tip usually being more flexible than the relatively stiff main mast. In the drawing the main mast 2 is shown within a part cut out section of the luff sleeve 1 1 below the head

(not shown) of the sail 1. A mast extension piece or tip 29, of a flexible material ' and having a tapering profile is shown being inserted into the hollow end of the mast 2 within the hole defined by an annular socket 30 secured to the end thereof. Stitched to either side of the luff sleeve 11 is a length of webbing 31 which spans the central portion of the sleeve and includes an eyelet 32 of size sufficient to permit the mast extension or tip 29 to be received therein. The drawing therefore shows the sailing apparatus in accordance with the second embodiment of the invention in a semi-assembled state and it will be readily apparent that when the mast extension piece is fully inserted into socket 30 upon downhaul tension being applied to the luff sleeve 1 1 in the direction arrowed the strap 31 and eyelet 32 will move downwards until it rests upon the socket 30 in which position the free end of the mast tip or extension piece 29 is then directly above and coaxial with the mast 30 but is substantially unaffected by downhaul tension applied to the luff sleeve 1 1. Hence, the mast tip or extension piece 29 can be used to support the head of the sail 1 with consequent advantages as outlined earlier.

The invention therefore provides a neat and effective way for the sail to automatically de-tune itself in high wind speed conditions whilst maximizing the use of the force expended by the wind in bending the upper mast section when the wind speed decreases. This same effect also permits the maximum amount of power to be extracted from the sail when it is initially being pumped to achieve start-up speed.