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PhilUK said..

Wouldnt it be cheaper to shave some material off the cam? As in the video SurferKris posted earlier.
Or if thats not possible, check other makes cams to see if they are shorter than yours. eg Duotone have/had different length of cams on their sails iirc. I dont know if their latest adjustable ones are all 1 size or not.

In my experience: no, not at all. Actually those cams need shims to be added, not grinding.
To me it's a matter of the "bottleneck" shape in SDM masts: abrupt diameter variations lead to uneven stiffness, too much of it in the lower cams zone.

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PhilUK said..

Wouldnt it be cheaper to shave some material off the cam? As in the video SurferKris posted earlier.
Or if thats not possible, check other makes cams to see if they are shorter than yours. eg Duotone have/had different length of cams on their sails iirc. I dont know if their latest adjustable ones are all 1 size or not.

Yes, the Duotone adjustable "Hyper Cam 2.0" ones come in four sizes (smaller to larger, labeled a - b - c - d from top to bottom)

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bel29 said..

PhilUK said..

Wouldnt it be cheaper to shave some material off the cam? As in the video SurferKris posted earlier.
Or if thats not possible, check other makes cams to see if they are shorter than yours. eg Duotone have/had different length of cams on their sails iirc. I dont know if their latest adjustable ones are all 1 size or not.

Yes, the Duotone adjustable "Hyper Cam 2.0" ones come in four sizes (smaller to larger, labeled a - b - c - d from top to bottom)

Interesting. Although if you did want to use a Duotone v2.0 cam in your brand x sail you would also have to make sure that the jaws of the cam would match your mast as well, and also find someone willing to let you try their cams from their sails.

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PhilUK said..

Interesting. Although if you did want to use a Duotone v2.0 cam in your brand x sail you would also have to make sure that the jaws of the cam would match your mast as well, and also find someone willing to let you try their cams from their sails.

in principle, yes, but the roller design may make them a bit more forgiving in that respect -- although I haven't yet tried them on non-duotone masts so definitely 'try before you buy'. I love the adjustability of these and their simple design, allows for easy sail trimming and instant feedback without having to derig the sail -- a real gamechanger imho.

www.duotonesports.com/en/products/hyper-cam-2-0-14200-8112?variant=46560424788292

... and this one is the 8.2 '22 Venom, that showed even worse rotation issues than the 7.5 sibling!
This one too, rigged on an MDM 460 mast from an Italian manufacturer.
The sail shape seems nice to me, maybe a tad on the "soft-top-ish" side. 1 shim at cam #1, 2 shims at cam #2. Base 30 cms + another 2 due to the RDM to MDM adapter, about 1 cm slack between pulleys, so in total it's 31 cms as per spec.
?si=0L_KB1DCj_Hd1MLT

From the videos it looks like you are using a lot of downhaul. In my experience it seems they really don't need more than what has been posted in the rigging tutorial by Justine. I'll be in Denmark from April 21st, so I might have a chance to give them a proper workout. How was rotation with the MDM without any spacers?

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Krautsurfer said..
From the videos it looks like you are using a lot of downhaul. In my experience it seems they really don't need more than what has been posted in the rigging tutorial by Justine. I'll be in Denmark from April 21st, so I might have a chance to give them a proper workout. How was rotation with the MDM without any spacers?

I really can't tell.
I looked for the right sail shape actually and downhauled accordingly. Don't know if downhaul force used with this MDM is higher, and by how much, than it would have been with the Venom SDM mast (but probably not lower than that).
I applied enough downhaul to have the leech open from batten #3 up. This for some reason resulted in setting to the suggested specs: + 31 extension, 229 boom (slightly positive). This way the entry is not overly round and as you see rotation is just sweet for a 4-cams beast.
Same for the 7.5 (at + 20 and 219 of course).
I could let go .5 - 1.0 cms and get firmer leech, but I think it's better the way you see. Need test on the water to tell anyhow.
The sail in the video from Justine is a 6.2, it goes on a 430 mast and in my experience is completely different. Much softer, cams rotating perfectly on its "own" Venom 430 mast.
You also have to consider that what you see here (my videos) is sails flipping around their zero AoA position, so they may look "flapping" and overly downhauled.
Also, the mast is theorically waaay off of spec.
In fact this all is to tell that:
MDM masts can be a solution for rotation issues;
MDMs behave in a completely different way than SDMs;
a 460/25/62/77 MDM can make work a sail that asks for a 460/25/63-65/74-76 SDM and does not rotate on its specific mast.

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Krautsurfer said..
...
How was rotation with the MDM without any spacers?

Sorry I forgot to answer this.
With MDM mast and no spacers, rotation was the same as with the spacers on.
Rigging with the recommended SDM mast it was the same.

Had a few sessions with both 7.5 and 8.2 the last week. As said before, cams won't rotate on land with no wind. With a bit of wind on the water rotation is absolutely not an issue, they just pop around. Even the bottom one, which is usually the sticky one in race sails, does rotate without an issue. Streamlined extensions set to 22 and 32 cm with a cm off the block. Hopefully 20+ kn tomorrow so I can get the 6.6 Hucker out of the bag ...

I had the same problem, shaved the cams back on all bottom 3, fixed perfect rotation

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geoITA said..

I really can't tell.
...
In fact this all is to tell that:
MDM masts can be a solution for rotation issues;
MDMs behave in a completely different way than SDMs;
a 460/25/62/77 MDM can make work a sail that asks for a 460/25/63-65/74-76 SDM and does not rotate on its specific mast.

In the meantime, I di the IMCS test on this last MDM mast. It was supposed to be a 460/25/62/77, turned out to be 460/25.5/63/79 (!!!) so a 15 curve, definitely a flextop (in fact it was supposed to be used on NeilPryde sails).
Now a new one MDM proto is coming, overall stiffer and with a stiffer top. We will see how it goes ... hopefully just OK for most sails around, apart maybe from NP/Gun/Duotone.

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Kym Roberts said..
I had the same problem, shaved the cams back on all bottom 3, fixed perfect rotation

S2Maui Venom 7.5 and 8.2 sails?
Generally shaving off the cams works if cams are too tight (of course), which is not the case with the '22 Venoms.

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Krautsurfer said..
Had a few sessions with both 7.5 and 8.2 the last week. As said before, cams won't rotate on land with no wind. With a bit of wind on the water rotation is absolutely not an issue, they just pop around. Even the bottom one, which is usually the sticky one in race sails, does rotate without an issue. Streamlined extensions set to 22 and 32 cm with a cm off the block. Hopefully 20+ kn tomorrow so I can get the 6.6 Hucker out of the bag ...

You got a "good" mast, from previous production. With those ones rotation is not an issue at all. I checked myself recently with a mast borrowed from a friend, even sail shape changes dramatically, with a finer entry under the boom.
The problem happens with '22 and onward masts.
As I can not get older models any more, I am resorting to MDMs.

Hi all, after one more sailing season and all the tests and experiments, here is my conclusion.
I sailed my '22 Venom 7.5 with an MDM proto mast, in conditions ranging from barely planing to barely keeping it all together. It is a 460/25/15. The rig behaved perfectly well: camber rotation is super nice, the sail feels plenty powerful, control is ... S2Maui style. This mast is now my #1 choice with the 7.5.
In one occasion (one only, sorry) I also sailed my Venom 8.2 rigged on another proto MDM mast, 460/27/13, in 12 - 15 kts gusting to maybe 18. FMX Invictus 128 and 43 fin. The sail showed the same easy cam rotation, plenty of power, very direct feel. Easier to get planing, still very easy to control, though maybe a tad less "automatic".
The 8.2 Venom rigged on a typical 460/25 mast usually displays rather a "large medium wind sail" feel rather than a more useful and versatile "smaller light wind sail"; this 460/27/13 MDM mast makes a better light wind sail of it.
I tried to rig a Severne M5 7.8 sail on the S2Maui Venom 460 mast, and it showed a perfect shape and perfect cam rotation on land. Did not sail it, but really seemed perfect. I received confirms from different sources that the Venom mast is actually a perfect choice for the Severnes, probably preferable to the delicate original Severne mast.
I was also confirmed from different sources that the "drop shape" masts need special reinforcements where the diameter reduction is in order to resist stress concentration, making that section overly stiff.
I still have to sail the 8.2 with the softer mast, as well as the 7.5 with the stiffer one.
For me, the MDM masts, with NO abrupt diameter reduction areas, are from now on the best choice for all (cambered) sails in order to avoid any problems. So I will hopefully be able to make the tests I wasn't able to do so far (7.5 with the 460/27 mast and 8.2 with the 460/25 one), then take a decision and have onother 1 - 2 460 masts manufactured (to be decided if 25, 27, or maybe an intemediate 26 if possible) plus a couple 430, plus few more for my friends.
In order to rig those masts properly, in the end I bought a NorthSails MDM mast extension. I am very glad of that, too, as it seems very practical to use and well built. Alternatively, I also had a few adaptors made to use the MDM masts with RDM extensions.
Having solved, and very brilliantly, the mast issue with the S2Maui Venom, I have no reason to make do with different sailmakers. So I am thinking about ordering some new '25 Venom sails when available from my usual supplier.
The proto 460/25/15 mast I used will probably be be listed in the catalogue of a major sailmaker in the next months, together with its 490 sibling. And this is very smart of them, in my view.

Hi everyone,

I've been struggling with my Venom 7.5 2024 sail-the cam rotation was really difficult and seemed to get harder the longer the sail was rigged.

I tried everything: adjusting batten tension, adding and removing spacers, and even shaving down the cambers. Unfortunately, nothing seemed to help.

But I think I've found the issue and wanted to share it in case it helps others. It turns out that the batten tips on battens 4, 5, 6, and 7 were too soft. This allowed the cambers to rotate too far, making them very difficult to flip.

I replaced these battens with new ones from S2Maui, and it's made a big difference-the rotation is much smoother now.

Hope this helps fellow sailors who might be experiencing the same problem!

Cheers,

I have an S2 6.3 2019 ish
popped beautifully and had great power until i washed up in a shore break and busted a bunch of batterns.
I replaced like for like, properly.
but its a dog now, just cant get it right, its a shame because it was a bloody power house of a sail.
by the sounds of it, these things needca pit crew to get them going properly. but once they are there, they are red hot

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TREM819 said..
Hi everyone,

I've been struggling with my Venom 7.5 2024 sail-the cam rotation was really difficult and seemed to get harder the longer the sail was rigged.

I tried everything: adjusting batten tension, adding and removing spacers, and even shaving down the cambers. Unfortunately, nothing seemed to help.

But I think I've found the issue and wanted to share it in case it helps others. It turns out that the batten tips on battens 4, 5, 6, and 7 were too soft. This allowed the cambers to rotate too far, making them very difficult to flip.

I replaced these battens with new ones from S2Maui, and it's made a big difference-the rotation is much smoother now.

Hope this helps fellow sailors who might be experiencing the same problem!

Cheers,

I agree with you, indeed those soft batten tips amount to a large part of the problem!

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shark02 said..
I have an S2 6.3 2019 ish
popped beautifully and had great power until i washed up in a shore break and busted a bunch of batterns.
I replaced like for like, properly.
but its a dog now, just cant get it right, its a shame because it was a bloody power house of a sail.
by the sounds of it, these things needca pit crew to get them going properly. but once they are there, they are red hot

Maybe broken battens were not the only damaged parts. Can not tell for sure, but sail materials may stretch. If the load was enough to break battens, probably it did more than that.