Forums > Windsurfing General

Cam rotates way better with less downhaul. Why?

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Created by thedoor > 9 months ago, 3 Aug 2024
thedoor
2469 posts
3 Aug 2024 10:18AM
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I have struggled for a while with cam rotation on my single cam point-7. Anyways today I fiddled around on land to see if batten tension would make any difference. Which it didn't at least for the things I tried.

Finally I tried releasing downhaul about one inch and it worked it immediately rotated on first try. Does that make sense?

PS I set my extension about one inch less than spec and generally downhaul this sail until the second from top panel gets a divot as per the "cam won't rotate" picture. When I got the sail it had some markers on that panel but they fell off.



PPS I like how the sail pumps and rides. Just annoying to have to manually pop the cam after gybing

Subsonic
WA, 3354 posts
3 Aug 2024 11:53AM
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Sometimes they go a bit overboard with the space they give the cam in the pocket ( or alternatively, it's not the correct mast, or it's stretched) if the cam has space between it and the mast, or not quite enough tension then it will be reluctant to rotate. That's why backing the downhaul off makes it rotate again, the cam is on more of a loaded angle, and has the load on the mast again to rotate around. The actual fix would be to add spacers to bring the tension and contact with mast back to where it should be at the proper downhaul, because no one likes an under downhauled sail.


thats my (educated) guess on what's going on.

Imax1
QLD, 4925 posts
3 Aug 2024 3:13PM
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I yank hard with the back hand when flipping the sail to rotate stubborn cams. It's worth a try if you haven't. Works a treat for me. I also agree that an under down hauled sail feels yucky.

thedoor
2469 posts
3 Aug 2024 6:53PM
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Select to expand quote
Subsonic said..
Sometimes they go a bit overboard with the space they give the cam in the pocket ( or alternatively, it's not the correct mast, or it's stretched) if the cam has space between it and the mast, or not quite enough tension then it will be reluctant to rotate. That's why backing the downhaul off makes it rotate again, the cam is on more of a loaded angle, and has the load on the mast again to rotate around. The actual fix would be to add spacers to bring the tension and contact with mast back to where it should be at the proper downhaul, because no one likes an under downhauled sail.


thats my (educated) guess on what's going on.


Oh cool. I have spacers I will try that

thedoor
2469 posts
4 Aug 2024 4:55AM
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I was a bit skeptical subsonic first I tried one of the large spacers without luck even with less downhaul, so I added a second large spacer, still no luck. So I started screwing around with the battens no luck either. However when I remove the two large and put in one small spacer it was immediately rotating with moderate downhaul. This was the 6.4. hopefully it works on the water



elmo
WA, 8868 posts
4 Aug 2024 5:50AM
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Check the back of the sail, if the sail is touching the back of the boom it can create resistance to the cam rotating as the batten has to bend into a wierd "S" pattern to allow the sail to rotate.

Gestalt
QLD, 14627 posts
4 Aug 2024 8:31AM
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The bottom batten looks to be under tensioned too. FWIW

Subsonic
WA, 3354 posts
4 Aug 2024 7:23AM
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Select to expand quote
thedoor said..
I was a bit skeptical subsonic first I tried one of the large spacers without luck even with less downhaul, so I added a second large spacer, still no luck. So I started screwing around with the battens no luck either. However when I remove the two large and put in one small spacer it was immediately rotating with moderate downhaul. This was the 6.4. hopefully it works on the water




Yeah, its a bit of finding the right tension. Too much tension isn't good either.

i had a foil sail do it to me, that's where the education came from. Hope it works out for you.

thedoor
2469 posts
4 Aug 2024 9:50AM
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Thanks all and more update: it was much better on the water until the later part of the session, which incidently coincided with me adding more outhaul not cause I was OP more because I was underpowered and I was struggling to gain ground upwind. I wonder if that might relate to elmos comment about the clew touching the boom, although I don't think it was fully outhauled

Re bottom batten tension: I have been running it a bit low after an initial consult with semi-pro rider re the failure to rotate. This was pre spacer maybe can add more now



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"Cam rotates way better with less downhaul. Why?" started by thedoor