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Old 8th October 2009, 11:11 AM   #3
Roger
Dream Team - School Guru
 
Join Date: Aug 2006
Posts: 2,092
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Hi PH68,
Thanks Ken, good suggestions!
First, can you tell us which race sails you are using, and do they have roller cams?
As Ken suggests, the correct downhaul and outhaul are very important to cam rotation.
Too little downhaul and the mast does not bend the correct amount and some of your cams will be underloaded, others overloaded. With the correct downhaul, the seam down the front of the sail should bear at pretty much the same angle in front of each cam.
If you see that the upper and lower cams are about right, and the middle cams are under rotated (the seam is less far around the mast) then you need more downhaul to bend the mast more in the middle.
So, check the angles of the seam/crease (from the center of the mast measured around from the front of the mast). It may be on your masts you need some additional downhaul to get the angles all the same.
Also when your sail is rigged, check the tension of the luff sleeve adjacent to each camber. You can "flick it" with your finger and the sound should be about the same for all of your cams. If it's too tight it will sound loud/sharp, and if you don't have enough tension the sound will be softer/duller.
If you have roller cams, check for proper rotation of the rollers.
Also check if there are shims between the convex saddles on the front of the batten adapter and the concave saddles in the back of the cam.
The McLube Sail Kote that Ken suggests can be very helpful, but also check your mast is the areas the cambers ride to ensure that it's smooth to help with easy cam rotation.
Outhaul is also important, since if you run negative outhaul, there is no clew tension until you load things up.
Also do you give a quick snap with both hands when trying to get the cams to rotate?
Can you send me a photo of your sail (s) the way you rig them and perhaps a photo of one of the cambers and the front of the batten adapter?
You sometimes have to sacrifice a little performance (if you are not racing) and file the back of the cambers to loosen them up a little.
The also need to fit the radius of the mast almost perfectly. If the cams are too big, you don't get good rotation due to point loading, and if the cams are too small in radius you get lots of drag on the points of that are supposed to be tangent to the side of the mast.
Could be lots of little tuning things with each cam, and sometimes you have to fit and file a bit to get the best rotation with good performance.
The luff sleeve cannot be really loose (not enough cam tension or not enough mast bend) but conversely they cannot be too tight.
Larger sailors/racers normally run the tension in their luff sleeve/cambers pretty tight, but they have the brawn to snap them over.
Smaller sailors (like me) tend to run the luff tension/cambers a little looser by either tuning the cams individually or backing off a little on the batten tension.
Hope this helps,
Roger is offline   Reply With Quote