Forums > Land Yacht Sailing General

Cammed sails

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Created by Bynorthsea 3 months ago, 23 Jul 2019
Bynorthsea
104 posts
23 Jul 2019 12:45AM
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Of the sails I use I have sort of arrived at the view that my flat sails I have are easier to set up and better to sail with than the couple of cammed sails I have. However I have a couple of cammed sails and yesterday I thought I would have another go with my 6m. Went reasonably well, probably a bit better in the very light wind but the one issue I have is I have to turn right onto the wind, and yank the boom to get the bottom batten to pop, the flat sails pop much earlier and with less wind pressure. So question for you can I get the sail to pop earlier and with less pressure, is it just a matter of easing the pressure on the battens, or????????
Cheers Les

Chook2
WA, 1216 posts
23 Jul 2019 11:10AM
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Hi, because our masts are bottom mounted and reinforced internally there is much less bend in the mast at that point. Sometimes the sail requires a hand slap in really light conditions or when your stopped to get them to change sides/pop through. (while sheeting in.)
Unlike windsurfers we cant pump the boom to get the cambers to pop through.

You may have a damaged camber or the end of the batten is actually snapped off. ( Due to the cams not being removed properly, in our case with tension still on the sheet rope, or windsurfers releasing the downhaul too far too quickly ) They ping off hard smashing something. I've fixed a few on my second hand sails. Some "Severn" sails are a pain as the batten tip is stitched in.

To set up, rig your sail and pull only the sheet rope (NO DOWNHAUL) hard till the mast bends into the front of the sails mast pocket. The mast will be laying on top of all the battens before you add sheet tension. The cams will then simply pop onto the mast if you get this sheet rope tension correct. If they wont slip into their positions easily then the sheet tension isn't right. With experience you will work out how much tension is required to clip/unclip them.

Fit cams by pushing down on the rear of the camber hard with your hand through the zip opening while lifting the front rollers onto the mast using your other thumb over the mast as a fulcrum outside the mast pocket. With the "correct" sheet tension they simply pop on. Much swearing happens till this correct tension is established!!

WARNING If adjusting batten tension.
If the batten tension is not simply adjusted with an allen key, then it is a good idea to back off your downhaul (While still sheeted in) and remove the cams from the mast before undoing the batten tensioner end, as there can be a huge tension on the plastic "over centred" adjustment levers and if they are aged a bit/brittle they snap off. They are not easy to replace as unstitching is involved and a new one fitted to the dyneema cord and then all restitched. Cambered battens have lots of tension which removes all the wrinkles along the batten pocket/sail.

When de-rigging, ALWAYS tie your sheet rope with a bit of tension and then relax the downhaul totally and then just pop the cams off easilly.

A cambered sail "sometimes" likes a firm outhaul because our boom is much lower than when windsurfing. So try that too. If the outhaul clew/eyelet is up from the bottom of the sail don't be afraid to take your boom up to it and overlap the boom with the sail as it makes very little difference when sailing. We sew on a re-enforced triangle with a new clew to keep it all neat.

More downhaul usually helps the cambers to change sides/pop through, but if this still doesn't work (and seeing that the other cambers are changing sides easily) I would certainly go ahead and ease of the batten tension. The bottom batten doesn't usually add much sail tension anyway.
Maybe even try more tension if all this fails, as sometimes particularly "Neil Pryde race sails" have more shape here due to our booms being bottom mounted and this pulls differently from where the sail designer intended.

Hope this gets you onto the right track. You will love them at higher speeds, as when you sheet out when way overpowered in a gust they twist off and there is absolutely no sail shake. You can sail them in much higher wind conditions and still have full control due to this.

Have fun.

Bynorthsea
104 posts
24 Jul 2019 5:31AM
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Thanks again Chook always good to read your advice. Had a go today at rigging as you described but even sheeted in block to block there is no way to snap the cams on. I sheet down to the back of the seat and I think it flexing too much to get enough pull down, also the the zipped pockets are oddly midway between the cams so no way to get in.
I think you do make a real good point about the effect of the outhaul on the batten not popping. Fitting the extra corner on the sail has meant there is now no outward pull anywhere near the batten, I am going to look at re cutting the extension and the sail foot to improve the situation.

Chook2
WA, 1216 posts
24 Jul 2019 2:04PM
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Awww don't cut the foot if at all possible!!!!!
That is where all the strength of the sail is for down hauling it. Lift the sail up the mast using an extension on the tip rather than cutting the bottom.

Try backing off the sheet pressure gradually, as there is a real "Sweet spot" that allows the cams to clip on. Fully sheeted in wont work as it tightens up the mast pocket too much making it impossible to have enough room/slack in the material to maneuver the cam.

Seeing you cant get inside the mast pocket just push on top of the cams tail right at the exit of the batten to apply downward force while lifting the front.
Trust me there is a way.

kennatt
53 posts
24 Jul 2019 3:02PM
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Its a very common situation some sails are worse than others,and require a hard yank on the back of the windsurfer boom to get rotation,others simply slip round. try experimenting with more or less downhaul. One of my racing sails 7.7m severn code red,needs fully downhauling ,then gybing to get the battons half way round,then easing the downhaul until they pop round. You may find that just simply taking the bottom batton off has little effect on the sails performance , or takeing that cam off and leave the batton in may sort it. Some sails have closed batton ends pockets, others have the batton straight into the cam,so latter would work but former would need some stitching to hold batton in at boom end.

Bynorthsea
104 posts
27 Jul 2019 1:15AM
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Well guys scissors were already out, the foot of the sail as it was just did not let me get it as low as I prefer and the outhaul was not putting any pull on the leach edge. Did not take off much but altering the angle allowed me to get the sail low, a good fit to the boom and a more effective outhaul. I have not cracked popping on the cams but sliding the mast up in the cams is easy. So its cut, rebuilt, shapes up ok and ready to test.


Chook2
WA, 1216 posts
27 Jul 2019 5:36PM
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Ah nice work with a great result.
I my mind I had pictured your sail as big mast pocket sail with roller cams. WRONG!!! Sorry bout that.
Some of my older camed sails had a "yoke style" cams that you just fed the mast up through. My Demon 9.5m2 sail has 7 cams like this.
Looks like you have sorted it out very nicely.



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"Cammed sails" started by Bynorthsea