GB2496619A

GB2496619A - Furling sail apparatus with coilable battens

Info

Publication number: GB2496619A
Application number: GB1119750.6A
Authority: GB
Inventors: Dan Primrose; Simon Fry
Original assignee: PRIMROSE FRY TECHNOLOGIES Ltd
Current assignee: PRIMROSE FRY TECHNOLOGIES Ltd
Priority date: 2011-11-15
Filing date: 2011-11-15
Publication date: 2013-05-22
Also published as: GB2496752B; GB2496752A; US20130186320A1; GB201200248D0; GB201220575D0; GB201119750D0

Abstract

A sail apparatus having a sail 1 with one or more battens 7. A furling system varies the area of deployed sail between a furled state and an unfurled state by rotating the sail about a foil 15 at the leading edge. At least one batten comprises a single extendible sheet member operable to switch between a rigid three-dimensional longitudinal state and a coiled planar state, such that a deployed portion of said at least one batten is in said rigid, three-dimensional longitudinal state and a furled portion of said at least one batten is in a coiled planar state. The end of the batten (27, Fig 5A) closest to a leading edge of the sail may be chamfered to facilitate initiation between the two states. An extendible sheet member and a method of manufacturing an extendible sheet member are also disclosed.

Description

S

SAiL APPARATUS This invention relates to a sail apparaws, and in particular to a sail apparatus in which a sail is fin-led and unfurled about its leading edge. The invention also relates to an extendible member which may be used as a batten in the sail apparatus, and a method of manufacture therefor.

It is well known that battens can increase the area of a sail beyond the area which is directly supported by the tension within the sail. The additional area, sometimes referred to as the roach of the sail, is supported by the rigidity of the battens to maintain the desired aerodynamic profile. Battens are typically located toward the trailing edge of the sail and their main axis intersects the leading edge, sometimes referred to as the luff edge, of the sail.

A problem occurs when it is desired to use battens in combination with a sail rig in which the sail is flirled/unthried by winding/unwinding around an axis which nms along the leading edge of the sail. Such a roller-furling' sail rig allows the area of deployed sail to be easily and quickly varied. However, the rigidity of conventional battens is incompatible with winding the sail about the leading edge.

At least two different techniques have been used to address this problem. US 4,633,798 discusses using battens formed by a thin, resilient material having a curved, stable state but being deformable into a planar state for furling. In practical implementations, it has been typically necessary to employ two such battens facing each other, but even with two battens the stiflhess is not particularly high. In addition, the stresses applied to the battens in the curled state as a result of the resilience of the battens tends to weaken the battens. Further, the battens may damage the sail material.

WO 94/14648 discusses an alternative technique utilising inflatable battens. The need for inflatiortJdeflatjon equipment makes this technique expensive, and also the valves are prone to failure. Further, the time taken to inflate and deflate the battens make them unsuitable for competitive sailing, and in certain circUmstances could be a safety concern.

An object of the present invention is to provide an alternative solution to the problem of using battens with a roller-furling' sail rig. Aspects of the invention are set out in the accompanying claims.

An embodiment of the invention comprises using sail battens formed by a single extendible sheet member which has two stable states: a rigid three-dimensional longitudinal state in which the sheet is arranged in an arc close to 3600 so as to be generally tubular; and a coiled planar state. In use, the extendible sheet member switches between the rigid three-dimensional longitudinal state and the coiled planar state at a position which varies in response to winding/unwinding the sail about its leading edge. In the rigid, three-dimensjpj longitudinal state, the extendible sheet member stiffens the sail to provide an effective roach area. The coiled planar state allows the sail to be furled/unfurled using a roller-furling' sail rig.

WO 97/35706, the whole contents of which are hereby incorporated by reference, discusses an extendible sheet member which can be adapted for use in the present invention.

The extendible sheet member of WO 97/35706 has two stable states, a tubular extended state and a planar coiled state. Transition between the two states is effected by direct manual manipulation For the purposes of the present invention, such direct manual manipulation is not feasible. Accordingly, in a preferred embodiment, the extendible sheet member of WO 97/35 706 is modified by chamfering one end when in the tubular state, and preferably splaying the chamfered end, so that at a transition point between the rigid, three-dimensional longitudinal state and the coiled planar state forms an arc having an extent of not more than 1800. In this way, the act of winding/unwinding the sail about the leading edge causes the transition point between the tubular extended state and the coiled planar to move along the length of the extendible sheet member so as to remain adjacent to the leading edge as the sail is fi1rledJunfije without the need for any direct manual manipulation of the extendible sheet member.

The modifications made to the extendible sheet member of \kO 97/35706 are considered to be inventive independent of the sailing application, and would be advantageous in other applications where direct manual manipulation of the extendible sheet member is either unfeasible or undesirable.

Exemplazy embodiments of the invention will now be described with reference to the accompanying drawings, in which: Figure 1 schematically shows sail apparatus according to the present invention attached to a mast; Figure 2 schematically shows a sectional view through the sail apparatus and mast of Figure 1 with the sail in an unfurled state; Figure 3 schematically shows a sectional view through the sail apparatus and mast of Figure 1 with the sail in a partially ñwled state; Figure 4 schematically shows a batten member forming part of the sail apparatus of Figure 1, with one end of the batten member in a planar coiled state and the other end of the batten member in a three-dimensional longitudinal state; Figures SA and SB schematicaliy show views of a batten member forming part of the sail apparatus illustrated in Figure 1, with the entire length of the batten member in the three-dimensional longitudinal state; Figure 6 schematically shows the batten member illustrated in Figure 4 partially wrapped around a foil; Figures 7 and S show schematic views of an inner end of the batten member illustrated in Figures 5A and SB in situ in a sail pocket in an unfurled state; Figure 9 shows a section through the lines A-A illustrated in Figure 8; Figures 10 and 11 show schematic views of the inner end of the batten member illustrated in Figures 5A and 58 in situ in a sail pocket in a partially furled state; Figures 12A and 12B respectively show schematic sectional views through the lines B-B and C-C illustrated in Figure 10; Figure 13 schematically shows sail apparatus according to the invention attached to a Stay; Figure 14 schematicajiy shows a sectional view through the sail apparatus and stay of Figure 13 in an unfurled state; and Figure 15 schematically shows a sectional view through the sail apparatus and stay of Figure 13 in a partially furled state.

A first embodiment of the invention will now be described with reference to Figures 1 to 12. As shown in Figure 1, in the first embodiment a sail I is a mainsail mounted to a mast 3 and a boom 5. The sail us provided with a plurality of battens 7a-7d to maintain a roach area of the sail in an aerodynamic profile where the tension within the sail would not normally do so. A roiler-fhrling' sail rigging is employed in which, as shown in Figure 2, thc leading edge 9 of the sail I is threadcd onto a rotatable foil 15, and the sail 1 is wound and unwound about its leading edge 9 so that the furled portion of the sail I is within the mast 3 (see Figure 3). The acts of winding and unwinding the sail I can be referred to as rolling.

The furling system of this embodiment is provided with actuators (not shown) which apply a force to the trailing edge 11 of the sail 1 in a direction along the boom 5 away from the mast 3 to unfurl the sail 1 and which apply a rotational force to the foil 15 to thri the sail I. These actuators may either be motoriseci, pneumatic or manually driven using, for

example, a winch.

Figure 2 shows a cross-section through the foil 15 and the sail I when the sail 1 is in an unfurled state. As shown, the batten 7 is held in a pocket 2] formed on arm the sail 1. In the unfurled state, the batten is in a rigid longitudinal state. The sail 1 is furled by rotating the foil 15 about a roll axis, and the pocket 2lis formed on the side of the sail 1 which faces inwards toward the roll axis when the sail I is furled. Figure 3 shows a cross-section through the foil 15 and the sail 1 with the sail in a partially wowid state and the pocket 21 not shown separately from the batten 7 for ease of illustration. The portion of the batten 7 which is furled around the foil is in a planar coiled state. An important feature of the extendible sheet members used in this embodiment is that they are stable both in the three-dimensional rigid state and the planar coiled state, and can transition many times between those two states without excessive wear. Accordingly, the sail and battens can be furled and unfurled many times before needing to be replaced.

IS In this embodiment, the battens are made using the extendible sheet members discussed in WO 97/35706. Such extendible sheet members are available from Rojatube Technology, 130 Wellworthy Road, Ampress Park, Lymington, S041 SJY, UK. To make the extendible sheet member of WO 97/35706 suitable for use as a sail batten, various modificatio need to be made. Figures 5, 5A and SB show batten members after such modification. As shown in Figure 4, an end 25 of the batten 7 which, in use, is proximate the trailing edge 11 of the sail I has a rounded profile in a plane normal to the surface of the sail 1 and along the main axis of the batten 7. In this way, when the end 25 of the batten 7 is in the planar coiled state, there are no sharp edges which may damage the sail material and the transition from the three-dimensional longitudinal state to the planar coiled state is facilitated.

In order to facilitate furling of the sail 1, in this embodiment the end 27 of the batten 7 which, in use, is proximate to the leading edge 9 of the sail I is modified to facilitate initiation of the transition from the three-dimensional longitudinal state to the planar coiled state. In particular, as shown in Figures 5A and SB, the end 27 of the batten 7 is chamfered in the three-dimensional longitudinal state. In other words, the end 27 of the batten 7 adjacent the leading edge 9 of the sail 1 is obliquely angled with respect to the longitudinal axis of the batten 7 in the three-djmensioi longitudinal state. In addition, the end 27 of the batten 7 adjacent the leading edge 9 of the sail I is splayed in the three-dimensionai longitudinal state so that the arc formed by the cross-section of the extendible sheet member extends over a smaller angle than in the central portion of the batten 7 in the three-dimensional longitudinal state. In particular, the end of the batten 7 adjacent the leading edge 9 of the sail 1 is splayed such that at the transition between the three-dimensjoj longitudinal state and the planar coiled state the cross-section of the extendible sheet member forms an arc having an extent of not more than I X0°. This allows the extendible sheet member to be transjtioned between the three-dimensional longitudinal state and the planar coiled state simply by the action of winding the sail about its leading edge.

In this embodiment, the end 27 of the batten 7 proximate the leading edge 9 of the sail 1 is splayed by a thermoforming process in which the end is heated, shaped using a mould and then allowed to cool into the new shape.

For illustrative purposes, Figure 6 shows how the batten 7 may be partially wound around the foil iS in the planar coiled state and partially extending rigidly in the three-dimensjon& longitudinal state.

Figures 7 and S show the end 27 of the batten 7 proximate the leading edge 9 of the IS sail I in the pocket 21 with the sail 1 in an unfurled state. As shown, the batten 7 has a chamfered portion 35, which is closely acconlinodated in a first tapered pocket portion 37.

Figure 8 clearly shows that the chamfered portion 35 of the batten 7 has been splayed open.

The main portion 39 of the batten 7 is mounted in a second pocket portion 41 which is sufficiently wide to accept the batten 7 in its planar state. In this embodiment, the batten 7 has a diameter of 40mm in its three-dimensional longitudinal state and the width of the third pocket portion is just over 120mm. Figure 9 shows a cross-section through the main portion 39 of the batten 7 and the third pocket portion 41 when the batten 7 is in the three-dimensional longitudinal state. As shown in Figure 9, the cross-section of the extendible sheet member forms an arc of almost 3600 so that the batten 7 is generally tubular.

Figures 10 and 11 show the sail in a partially furled state such that the end 27 of the batten has started to wind around the foil IS. As shown in Figure 12A, the portion of the batten 7 away from the foil still has a generally tubular profile. However, as shown in Figure 12B, closer to the foil 15 the batten 7 has a more open, planar configuration in which the cross-section of the extendible sheet niember forms an arc of less than 1800.

In this embodiment the pocket 21 is formed of an elastic material. In this way, the pocket 21 contracts against the sail I during furling, allowing the fined sail to be more compact. However, using an elastic material for the pocket 21 is not essential.

MODIFICATIONS AND FURTHER EMBODLMENTS

In the first embodiment, the sail I is a mainsail whose leading edge 9 is attached to a foil 15 thin a mast 3. The invention is applicable to other sail apparaths in which a sail is wound and unwound about its leading edge. For example, as shown in Figures 13 to 15, in an alternative embodiment the invention is applied to a genoa sail 51 which is wound about a foil 53 attaches to a headstay 55. In another embodiment, the invention is applied to a code zero spinnaker which is wound about a stay.

The first embodiment discusses one way in which the end of a batten proximate the leading edge of the sail can be structured to facilitate the transition of the batten between the threedjmensjo1 longitudinal state and the coiled planar state by a rolling operation without any direct manual access to the batten. Alternative arrangements are possible. For example, the end of the batten proximate the leading edge of the sail could be permanently maintained in the coiled planar state by keeping a portion of the sail Permanently wound about its leading edge.

The modifications to the extendible sheet member of WO 97135706 made in the first embodiment may have application outside of a sail apparatus to facilitate transition of the extendible sheet member from the threedimejonal longitudinal stale to the planar coiled state without direct manual manipulation For example, such a mechanism could he used to deploy and retract an arm member in an unmwed deep sea vessel, or to retract a probe arm in a hazardous area.

While ii is preferred that the chamfered end of the batten be splayed, this is not essential.

While the extendible sheet member of WO 97/35706 is convenient for implementation of the present invention, alternative extendible sheet members which transition between two stable states, one in which the sheet member is in a threedjmensionai longitudinal state and the other in which the sheet member is in a pTanar coiled state, could be used.

Claims

<claim-text>CLAIMS1. Sail apparatus comprising: a sail having a eading edge and one or more battens; and a fining system operable to vary the area of deployed sail between a furled state and an unfurled state by rotating the sail about the leading edge, wherein at least one batten comprises a single extendible sheet member operable to switch between a rigid three-dimensional longitudinal state and a coiled planar state, such that a deployed portion of said at least one batten is in said rigid, three-dimensional longitudinal state and a Ilirled portion of said at least one batten is in a coiled planar state.</claim-text> <claim-text>2. Sail apparatus according to claim 1, wherein said rigid three-dimensional longitudinal state has a generally tubular profile.</claim-text> <claim-text>3. Sail apparatus according to claim 2, wherein the extendible sheet member has an outer end toward the trailing edge of the sail and an inner end toward the leading edge of the sail, wherein said inner end is chamfered to facilitate initiation of the transition from the rigid three-dimensional longitudinal state to the coiled planar state upon rotation of the sail about the leading edge.</claim-text> <claim-text>4. Sail apparatus according to claim 3, wherein said inner end is splayed such that a cross section through the cross-section of the extendible sheet member at a transition point between the rigid, three-dimensional longitudinal state and the coiled planar state forms an arc having an extent of not more than 1800.</claim-text> <claim-text>5. Sail apparatus according to claim 3 or 4, wherein the outer end of the extendible sheet member has a rounded profile in a plane normal to the surface of the sail and along the main axis of the batten.</claim-text> <claim-text>6. An extendible sheet member operable to switch between a rigid three-dimensional longitudinal state and a coiled planar state in which the extendible sheet member is coiled about a coil axis, the extendible sheet member having an end which is chamfered to facilitate initiation of a transition from said rigid three-dimensional longitudinal state to said coiledSplanar state in response to rotation of the extendible sheet member about the coil axis from said chamfered end.</claim-text> <claim-text>7. An extendible sheet member according to claim 6, wherein said chamfered end is splayed such that a cross section through the cross-section of the extendible sheet member at a transition point between the rigid, three-dimensional longitudinal state and the coiled planar state forms an arc having an extent of not more than I 50°.</claim-text> <claim-text>8. An extendible member according to claim 6 or 7, wherein the other end of the extendible sheet member has a rounded edge.</claim-text> <claim-text>9. A method of manufacturing an extendible sheet member, the method comprising: forming an extendible sheet member operable to switch between a rigid three-dimensional longitudinal state and a coiled planar state in which the extendible sheet member is coiled about a coil axis, wherein in said rigid three-dimensional longitudinal state the extendible sheet member has a generally tubular profile; and chamfering one end of the extendible sheet member.</claim-text> <claim-text>10. A method according to claim 9, further comprising the step of splaying said chamfered end.</claim-text> <claim-text>11. A method according to claim 10, wherein the extendible sheet member comprises a composite material, and said splaying step comprises heating and forming said chamfered end of the extendible sheet member.</claim-text> <claim-text>12. A method according to claim 11, wherein the composite material comprises a therrnoseffing or a thermoplastic material.</claim-text> <claim-text>13. Sail apparatus substantially as described herein with reference to the accompanying Figures.</claim-text>