Published by the Open Canoe Sailing Group

Our thanks to those who started the race and helped to time people at the finish, which allowed the meet organisers to take part.

Shorn Grows A Beard (RoyB)

A long awaited creation made its appearance at Coniston - JohnS's new boat. A 13' version of Shorn, so he says, with Bermudan main and jib (John is never one to skimp on sail area). It certainly looked good, and the maker pronounced himself satisfied. We met him at Loch Lomond one week later, where the conditions were lively at times. It came as no surprise to hear that John had successfully capsized - in only 4' of water, it should be added! We look forward to seeing more of this new design at future meets.

Designing A Junk Rig (Part 1) (RobertB)

Last year at Loch Lomond I tried out a small junk sail. The easy, reliable reefing and low loads make this rig especially suitable for canoes. The secret behind both is the full-length battens, with a sheetlet attached to each of them. The twist of most sails is controlled by leech tension. Effectively, leech tension must straighten out all the otherwise unsupported sail between the clew and the head of the sail. It is much like keeping a high wire from sagging - the longer the wire, the more tension is needed. The junk sail reduces loads by sheeting each batten and having only short lengths of unsupported sailcloth between battens. Neither the sheet, the sailcloth, the mast nor the rigging experience high loads. Having each batten sheeted also means that all battens are always being pulled down. Releasing the halyard makes the sail fold up neatly between the lazyjacks. The sail can be reefed one sail panel at a time, or all at once.

The arrangement of sheetlets and sheet is important. The principles are that there should be no large difference in sheet load between adjacent battens, and that the load should either be equal at all battens or it should increase from the lower battens to those higher up. The equal load arrangement will have more twist because the upper battens are sheeted at a less advantageous angle. Leading a higher proportion of the sheet load to the higher battens counteracts twist to some extent. Figure 1 shows one equal load sheeting pattern and two anti-twist patterns. Where the sheetlets meet they are usually run through a 'euphroe', a piece of wood with holes drilled through it. Blocks can be used to reduce friction.

For Figure 1, I have assumed that the main sheet would at most have a two-part purchase, so all sheetlets must meet in one point. There is a possible problem with that: as the sail is reefed there is a lot of spare sheetlet hanging down from the sail. A solution is to have a single sheetlet going to the boom, where it can be led forward to a cleat or another block. When reefing, some of the excess line can then simply be pulled in. The sheetlet can then even be used as a high purchase, fine adjustment. This is shown in all sheeting patterns in Figure 1.

Fig. 1.

Although the middle sheeting pattern has a very nice load distribution, it turns out to be utterly useless. Let's say the spacing between battens is 50 cm. When reefing, the outer euphroe would go down 1 m for each of the first 4 panels reefed, and another 50 cm for the 5th panel, even if the inner euphroe stays at the same height. The nearest to a reasonably simple anti-twist sheeting pattern I could come up with under these constraints is shown on the right of Figure 1. A three-part sheet doesn't need all the sheetlets meeting up in one point, so the extra lengths of string can gather in two shorter bundles. Examples of sheeting patterns are shown in Figure 2. Given these

Fig. 2.

principles and examples, it should be possible to work out new sheeting patterns for different numbers of battens.

(To be concluded next month)

Glorious Galloway - Dae Y'Ken? (EddieP)

On the weekend of May 6th and 7th, a few intrepid souls of the group who ventured into darkest Scotland had a wonderful weekend of hot weather and very good sailing, a mixture virtually unknown in Britain! Loch Ken had been visited by several people in the group before - both DaveT and I had wanted to organise a trip there at some time, and SueB and JohnE had kindly gone and seen the facilities at the Galloway Sailing Centre, which is near the northern end of the lake.

It's too easy to ladle on the superlatives, but we had a great time - friendly people, a laid-back

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