GB2204845A

GB2204845A - Removable mast clamp for sail boards

Info

Publication number: GB2204845A
Application number: GB08809973A
Authority: GB
Inventors: Stephen Molyneux
Original assignee: Individual
Current assignee: Individual
Priority date: 1987-04-30
Filing date: 1988-04-27
Publication date: 1988-11-23
Also published as: GB8710324D0; GB8809973D0

Abstract

A removable mast clamp for attachment of an uphaul rope to the mast of the sailboard independantly of the boom comprises an open ended collar (1, 2) shaped to fit round and grip the mast and a hole (7) to which the free end of the uphaul rope may be attached. The clamp can be formed in two pieces or moulded in one piece and the open end of the clamp including means whereby the ends may be drawn together to cause the collar to grip the mast and maintain its axial position thereon. <IMAGE>

Description

REMOVABLE MAST CLAMP FOR SAILBOARDS DESCRIPTION This invention relates to a removable mast clamp for fitting to the mast of a sailboard.

The pivotable mast and sail of a sailboard a-re raised into the upright position by means of an uphaul rope connected between the f-ront end of the boom or wishbone and the foot of the mast. The wishbone is located on th-e mast by a suitable lashing and its axial position along the mast can be adjusted over a length dependent on the cut-out provided for it in the sail.

The position of the boom/wishbone on the mast is normally dictated by the height of the person sailing the sailboard. The optimum height is shoulder level but if the person is particularly short, this can prove to be a problem because it means that the boom is located much lower down the mast and accordingly the amount of effort required to pivot the mast from its horizontal position laying in the water into its vertical position for sailing is much greater.

It is an object of the invention therefore to provide an improvement to the rigging of a sailboard which allows the boom to be positioned on the mast at a location which suits the sailor, but with the free end of the uphaul rope being attached to the mast independantly of the boom.

According to the broadest aspect of the invention there is provided a clamp for anchoring the uphaul rope of a sailboard to its mast at a location independant of the point of attachment of the wishbone, the clamp comprising anchoring means adapted to receive and retain one end of the uphaul rope and means for attaching said anchoring means to the mast to maintain its axial position thereon.

The anchoring means can be a block with a hole in it to receive and retain the uphaul rope therein.

Alternatively, it could be a simple ring to which the uphaul rope can be tied. In either case, the ring or block can be secured to the mast in any convenient manner using special clamping arrangements or even a simple lashing.

According to a preferred embodiment of the invention therefore there is provided a removable mast clamp for fitting to the mast of a sailboard independantly of the boom, the mast being raised into its sailing position by means of an uphaul rope, the clamp comprising an open ended collar shaped to fit round and grip the mast, means whereby the open ends of the collar may be drawn together to cause the collar to grip the mast and maintain its axial position thereon, the collar also including attachment means to which the free end of the uphaul rope may be attached.

In the preferred embodiment, the collar is formed in one-piece and is made of a resilient material which permits the open end of the collar to be enlarged to fit the collar around the mast. Alternatively, the collar may be made in two parts which may be hingedly connected together at one end. Conveniently, the means to draw the ppen end of the collar together can comprise a releasable latch of any convenient form or, at its simplest, it can comprise a rope lashing.

In another preferred embodiment, the two parts are separate, each part including connection means whereby it may be releasably connected to the other part, the connection means on each clamp part comprising a hole at one end and a horn at the other end. The arrangement is such that the two halves can be fitted together to clamp them to the mast by passing a rope through the two holes and then wrapping it round the respective horns to pull the two clamp parts together to grip the mast. Conveniently a cleat is provided on the clamp in which the free end of the rope may be locked.

Desirably, an anti-friction surface such as one or more rubber pads is provided on the inside face of the collar which contacts the mast. Other anti-friction devices could however be used.

Preferred embodiments of a mast clamp of the invention will now be described, by way of example only, with reference to the accompanying drawings in which: Figure 1 is a plan view of one form of mast clamp of the invention; Figure 2 is a perspective view of one half of the mast clamp shown in Figure 1; Figure 3 is a prespective view of a second form of mast clamp of the invention; and Figure 4 is a side view of a sailboard when fitted with a mast clamp of the invention.

Referring first to Figure 4, there is shown a conventional sailboard 15 to which the base of a mast 16 is pivotally attached at 23. A wishbone 21 is attached to the mast 16 in known manner at a height above the board to suit the person sailing it. The vertical distance through which the boom 21 can be moved on the mast 16 is dictated by cut-out 18 in sail 17. The mast 16 is raised from its horizontal position (when it is laying in the water) using uphaul rope 19, one end of which is attached to the base of the mast, its other end being attached to a mast clamp 20 of the invention which is attached to the mast indepentantly of the boom. In a conventional sailboard, the end of the uphaul rope 19 remote from the mast pivot 23 would normally be attached to front end 22 of the boom 21.

It will be seen from Figure 4 of the drawings that by using the mast clamp 20 of the invention, the boom 21 can be set in a low position to suit the person sailing the board whereas the uphaul rope 19 can be anchored to the mast at a much higher position thereby increasing the leverage available to the sailor to assist in raising the mast out of the water.

By way of example, if distance L1 is 1.2 metres, the maximum effort required to raise the mast will be approximately 15 KG. This would be the situation with a conventional sailboard if the free end of the uphaul rope was attached to the end 22 of the boom 21.

However, using the mast clamp 20 of the present invention, the boom 21 can be set in its lowest position but the distance L2 of the anchor point for the uphaul rope to the mast is increased. In the illustrated embodiment, if this distance was increased by 0.4 of a metre, the maximum effort to raise the mast would be approximately 12 KG which would represent a saving in effort of 20-25 %.

Referring now to Figures 1 and 2, there is shown a particular embodiment of a mast clamp 20 which can be used in the manner just described with reference to Figure 4. The mast clamp comprises clamp halves 1, 2, each of which is provided at one end with a hole 5, 6 and at its other end with a horn 3, 4. Respective recesses 11, 12 are formed behind the horns 3, 4.

The clamp half 1 is additionally formed with a hole 7 adapted to receive and anchor the end of the uphaul rope 19 remote from the sailboard. A hole 8 of smaller diameter is also provided in the clamp half 1 close to the uphaul anchor hole 7.

As can be seen more clearly in Figure 2, clamp half 2 is formed with a cleat 9 whose purpose will be described shortly.

The mast clamp halves 1, 2 are preferably moulded from a plastics material and the inside face of semi-circular cut-out 13, 14 has one or more anti-friction pads 10 attached thereto. Alternatively a single pad can be used to line the cut out 13, 14.

Conveniently, these pads are made of rubber but other materials could be used.

In order to attach the mast clamp 20 shown in Figures 1 and 2 to the mast 16 shown in Figure 4, a knot is tied in one end of a length of rope which is then fed through hole 5 and then back up through hole 6 thereby attaching the two mast clamp halves together. The connected mast clamp halves 1, 2 are then fitted round the mast 16 and the free end of the rope which passes through the holes 5 and 6 is then tightly wrapped around the horns 3, 4 to draw them together and tightly clamp the mast clamp halves around the mast. The free end of the rope is then locked in position in the jamming cleat 9 and the mast clamp is thereby securely attached to the mast 16 and cannot move axially thereon. The free end of the uphaul rope remote from the board 15 is then passed through the hole 7 and secured therein by tying a knot in the free end of the rope.If the rope used to secure the two mast clamp halves together protrudes beyond the jamming cleat 9, this can be fitted in n tidy" hole 8. Additionally, to provide a neat attachment, recesses 24, 25 can be provided adjacent holes 5, 6 and behind horns 3, 4 to facilitate lashing the two parts together.

It will appreciated that although the mast clamp described with reference to Figures 1 and 2 is formed in two halves, it is possible within the scope of the invention to make it as a one-piece moulding in which the two mast clamp halves 1 and 2 are formed as one.

As an alternative to the embodiments just described, the mast clamp can be formed in one piece as shown in Figure 3. In this embodiment, the clamp comprises a collar 31 formed at its free ends with horns 32a and 32b. A non-slip lining 33, preferably of rubber, is attached in any suitable way to the interior of the collar, for instance by means of lugs 34 which are a push fit through holes (not shown) in the collar. The lining 33 may, however, be glued to the collar 31.

Attachment means 35 are moulded at the apex of the collar 31 and include four holes 36-39 and a larger hole 40.

In order to attach the clamp 31 to a sailboard mast 16 (see Figure 4) a length of rope with a knot at one end is fed through hole 36. The clamp is then fitted round the mast 16 with the anti-friction lining in contact with the mast. The rope is then fed round the mast 16 and wound first round horn 32b and then round horn 32a and pulled taught to draw the horns 32a, 32b together so that the clamp tightly grips the mast 16.

The rope is normally wound 2 or 3 times round the horns 32 and the free end is then pushed into hole 39.

To prevent the lashing working loose, the free end of the rope is then fed in one direction through hole 37 and in the other direction through hole 38 to finish off the lashing. The clamp 31 is now tightly fitted to the mast 16.

The free end of the uphaul rope 19 can now be inserted into the larger hole 40 to complete the installation of the clamp on the sailboard as has already been described with reference to the earlier embodiments.

As further alternatives to the embodiments described and illustrated, the rear half 2 of the mast clamp could be omitted, the front half 1 being held to the mast by means of a lashing inserted in the hole 5 and anchored by and tensioned on horn 3. Alternatively, the front mast clamp half 1 could be quadrant shaped when viewed in plan and held against the mast by a lashing. At its simplest, the mast clamp can comprise a member with a hole in it to anchor the uphaul rope, said member being attached to the mast by a lashing. It could even comprise a ring attached to the mast by a lashing.

Claims

1. A clamp for anchoring the uphaul rope of a sailboard to its mast at a location independant of the point of attachment of the wishbone, the clamp comprising anchoring means adapted to receive and retain one end of the uphaul rope and means for attaching said anchoring means to the mast to maintain its axial position thereon.

2. A removable mast clamp for fitting to the mast of a sailboard independantly of the boom, the mast being raised into its sailing position by means of an uphaul rope, the clamp comprising an open ended collar shaped to fit round and grip the mast, means whereby the open ends of the collar may be drawn together to cause the collar to grip the mast and maintain its axial position thereon, the collar also including attachment means to which the free end of the uphaul rope may be attached.

3. A mast clamp as claimed in claim 2 wherein the collar is formed in one-piece and is made of a resilient material which permits the open end of the collar to be enlarged to fit the collar round the mast.

4. A mast clamp as claimed in claim 2 wherein the collar is in two parts.

5. A mast clamp as claimed in claim 4 wherein the two parts are hingedly connected together at one end.

6. A mast clamp as claimed in any one of claims 2 to 5 wherein the means to draw the open end of the collar together comprises a releasable catch.

7. A mast clamp as claimed in claim 4 wherein the two parts are separate, each part including connection means whereby it may be releasably connected to the other part.

8. A mast clamp as claimed in claim 7 wherein said connection means on each clamp part comprises a hole at one end and a horn at the other end, the arrangement being such that the two halves can be fitted together to clamp them to the mast by passing a rope through said two holes and then wrapping it round the respective horns.

9. A mast clamp as claimed in claim 8 wherein a cleat is provided on the clamp in which the free end of said rope may be locked.

10. A mast clamp as claimed in any one of claims 2 to 9 wherein the attachment means for the uphaul rope is a hole provided on the collar.

11. A mast clamp as claimed in claim 10 wherein an additional "tidy" hole is provided close to said hole.

12. A mast clamp as claimed in any one of claims 2 to 11 wherein an anti-friction surface is provided on the inside face of the collar which contacts the mast.

13. A mast clamp as claimed in any one of the preceding claims made of a plastics material.

14. A mast clamp substantially as herein described with reference to the accompany drawings.