Tuesday, November 09, 2010


Kim and I are back from Sydney having enjoyed the show we went to see, The Jersey Boys which told the story of Frankie Valli and the Four Seasons. The show is just awesome and I can recommend it to anyone, even if they are not Frankie Valli fans as the music is just brilliant. I wasn't aware of their story which traced their rocky rise to fame, and which was interupted by stints in gaol!

Anyway Valli aside, sailing wasn't on the agenda today as there is no wind at all, so it was some more driveway development for testing maybe next weekend.

I've installed the vang, reconfigured the downhaul, moved the sail attchment on the front of the boom back a bit, moved the yard attachment back to the 40% position, and added a 2:1 purchase on the clew adjustment.

Just to explain, I have been having issues with lee helm when close hauled. Hopefully these mods will sort that problem, and introduce some desirable slight weather helm.

This pictures show the vang installed, and the downhaul moved to to the front of the boom. Here the downhaul is pulled on so that the luff of the sail is 200mm in front of the mast. This is 200mm further back than the standard position of 400mm in front of the mast, and demonstrates one end of the available adjustment. This position moves the rig back for close hauled sailing and to induce (hopefully) some slight weather helm.

This next picture shows the downhaul released and some vang tension applied. You will see that the boom has now moved forward to place more of the sail to weather of the mast. The object here is to help balance the rig for downwind sailing and reduce rolling from side to side. It also balances the helm. Of course, in between these extremes is the ideal adjustment for the point of sailing (ie. close reaching or broad reaching) and the wind strength on the day. I have already played with this in actual sailing, but without the assistance of the vang which now makes the adjustments easier, and provides more control of both the luff and the leach.

The pics above show how the rig is easily adjusted while sailing. Ideally, with this set-up, the downhaul should be attached in front of the mast. With the downhaul currently fixed to the original fixture on the deck just to the left of the mast, it is binding slightly when the boom is gybed to starboard tack. If this arrangement works well in sailing, I'll move it to the front of the mast. The vang attachment is on the deck behind the mast, and this proved to be the correct place for it as there is no binding of the vang at all.

Notice I have applied traditional systems and have not used a cascading system for either the vang or the downhaul. The reason is because the cascading systems could not cope with the large amounts of movement and are better suited where the adjustment ranges are small. As you can see I just bolted the two single pulleys for the vang together to make a double.

Once the system is proved, then I will bring the controls back to cleats on the front edge of the seat. I don't want to drill holes unnecessarily at this stage.

These next two pics show the effect of the movement of the rig on the mainsheet. I had already moved the sheeting aft last weekend and found that this worked better for me. The rear sheeting does not interfere with the tiller as much, but the main thing I wanted to achieve with this arrangement was to prevent the boom being pushed forward when sheeting in hard. This arrangement works well to solve that issue. I can't say it will suit everyone, but I like it. The traveller is also adjustable via a clam cleat located beside BH4.

Finally, here is the simple 2:1 adjustment for the foot of the sail. The line runs around a sheave set into the end of the boom.

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