GB2317868A - Sailing apparatus - Google Patents

Abstract

Sailing apparatus suitable for windsurfing comprises a mast 2; a boom 3, securable at its forward end to the mast, a sail 1, including a luff sleeve 10, 11, for mounting the sail on the mast and attachment means in the form of an outhaul 5 at the clew for releasably securing it to the trailing end of the boom 3. The mast has a relatively stiff lower section 2b, and a relatively flexible upper section 2a, the latter providing support solely for the head 9, of the sail 1. Sail attachment means (13)(figs. 1 and 3), at the upper end of the lower section 2b, of the mast, supports the sail other than the head such that tension from a downhaul 4 is isolated from the head of the sail. Consequently gusts of wind automatically cause the head of the sail to bend the upper mast section 2a, to spill air (fig. 4) and thereby assist a user of the sailing apparatus to retain control in such conditions. The sections of the mast may be releasably connected by a ferrule arrangement, and the luff sleeves may be openable by means of fasteners 14a, 14b.

Description

fMPROVEMENTS IN AND RELATING TO SAILING APPARATUS 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 spill of the windsurfer. A larder 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 ofthe 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 ofthe board to lift. This allows air underneath the board which can upset the trim. Even so, skilled wind suffers are able to select the minimum movement of the clew end of the sail in order to retain control so as to masmize 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 This allows air to spill out ofthe leech in this region of the sail in gusty conditions. Some sail manufacturers even provide tnsfluctions 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 sijiifiocantly, 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 as the overall power which may be generated by the sail, particularly at low speed or in light Knd conditions, so that it only performs to its maximum efficiency in a relatively narrow range of conditions and speeds.

It is an object ofthe present invention to provide a sailing system for windsuig 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 the mast has two sections, a relatively stiff lower section and a relatively flexible upper section providing support solely for the head ofthe sail, and sail attachment means at the upper end of the lower section of mast for supporting the sail other than the head. such that in use, when the sail is mounted on the mast and is attached thereto by the sail attachment means at the upper end of the lower mast section, downhaul tension 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, mediurn 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 insertible in or on the upper end ofthe ]ower 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 characteristics 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 comprise 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 pin 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 ofthe 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 derring 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 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 altemately pulling and pushing the boom and hence sail in order to gather sufficient speed from a stationery or stalled condition. in conventional sails where the leech of the head is normally loose and therefore nor worlong 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 ofthe sail is wofiwig at all times. In addition, the flexibility of 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 the accompanying drawings in which: Figure 1 is a side view of sailing appamus according to the invention, Figure 2 is a view corresponding to Figure 1 but showing part sectional and part cut out portions ofthe upper parts ofthe sailing apparatus Figure 3 is a detailed view of mast and sail connector means according to an aspect ofthe invention, and Figure 4 is a font view of the sailing apparatus of Figure 1 depicting flexure of the upper section of mast and sail in high wind speed conditions.

In Figure 1 there is shown sailing apparatus comprising a windsurfing sal I of generally conventional type rigged on a mast 2 and a boom 3. A downElaul 4 at the foot ofthe mast 2 provides downhaul tension to the sail and an outhaul 5 tensions the sail 1 between the clew and the free end ofthe 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. Villus far, the sailing apparatus descnbed is of conventional configuration 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 main luff sleeve 11, each of which sleeves surround respective potions ofthe mast 2 when in use Between the head luff sleeve 10 and main' luff sleeve 11 is disposed mast connector means 12 and sail attachment means 13, each of which are descnbed more filly below with reference to Figure 3.

Turning now to Figure 2 there is shown part in cross section and part in cut out the sailing 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 11. The lower mast section 2b is comprised of a tubular composite fibre generally rigid material of frustaconical 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 ngid 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 fermles 1 spa, 1 5b 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 1 Sa, 1 5b are welded coaxially to respective sides ofthe 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 afthe upper mast section 2a and the corresponding movement of the head 9 ofthe 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 ofthe upper mast section 2a will occur but mcreasing wind speed will increase the amount of flexure. This will m 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 filly upnght 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 condinon where no power is produced in this area ofthe sail.

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.

Claims (10)

1. Claim 1. Sailing apparatus comprising a mast, a boom securable at its forward end to the mast, a sail including a luff sleeve for mounting on the mast and attachment means at the clew for relenwhly securing it to the trailing end of the boom, CHARACTERIZED IN THAT the mast has two sections, a relatively stiff lower section and a relatively flexible upper section providing support solely for the head of the sail, and sail attachment means at the upper end of the lower section of mast for supporting the sail other than the head, such that in use, when the sail is mounted on the mast and is attached thereto by the sail attachment means at the upper end of the lower mast section, downhaul tension is isolated from the head of the sail.
2. Claim 2. Sailing apparatus according to Claim 1 in which the mast is in two separate sections which can be releasibly connected together by connector means.
3. Claim 3. Sailing apparatus according to Claim 2 in which the connector means comprises a ferrule insertable in or on the upper end of the lower section of mast and is connected to a corwonding female for receiving the lower end of the upper section of mast to form one continuous mast when so connected.
4. Claim 4. Sailing apparatus according to Claim 2 or Claim 3 in which the sail attachment means is integral with the mast connector means.
5. Claim 5. Sailing apparatus according to any preceding claim m which the sail attachment means includes a lug incorporating a slot disposed in-line with the mast and including a releasable fastener for securing the forward edge of the sail just below the head.
6. Claim 6. Sailing apparatus according to Claim S in which the releasable fastener comprises a pin insertable through an eyelet at the fonard edge of the sail just below the head.
7. Claim?. Sailing apparatus according to any preceding Claim in which the luff sleeve at the head ofthe sail is separate to the luff sleeve below.
8. Claim 8. Sailing apparatus according to Claim 7 in which the luff sleeve at the head of the sail is openable along its length by means of a releasable fastener such asazipper.
9. Claim 9. Sailing apparatus according to any preceding Claim in which the head section ofthe sail at the luffis curved so as to force the upper mast section to adopt a correspondingly fixed curvature while the sail is ngged.
10. Claim 10. Sailing apparatus substantially as herein before described with reference to and as shown in the accompanying drawings.