I have bought a second- (or third-) hand Sail Loft Hamburg 2018 Ultimate 5.6m race-oriented sail and find that there is quite a lot of wrinkle in the (large) luff sleeve when I rig it on a Simmer R10 (100% prepreg carbon) 400 mast. I am experimenting with increasing the spacers behind the 4 cams to minimise the wrinkle, but am wondering how much extra bend the mast will tolerate. It occurred to me that mast makers must have some idea about the limits of their products, but I cannot find any info on Simmers or any other mast. I would be delighted if anyone can throw light on this for a poor, benighted windsurfer (of some 30 years experience but who, only now, is having to get into the technicalities of tuning cammed sails). I am also experimenting with different cams towards the same ends and would like comments on that. E.g. I cannot even get info about the effective length of cams (from batten "hilt" to mast) and even info about availability of cams is hard to get.

You won't bend a mast too far. Not when rigging it, that's for sure.

Trouble with cam sails is small variances in mast curve that you might get away with on other sails become very problematic
That means use the right mast. No idea if Simmer is identical that whatever Sail Loft specify, but its not quite constant curve so I suspect that is your problem. Sometimes no amount of spacers can make that go away

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taveray said..
.... I cannot find any info on Simmers or any other mast. I would be delighted if anyone can throw light on this for a poor, benighted windsurfer (of some 30 years experience but who, only now, is having to get into the technicalities of tuning cammed sails). I am also experimenting with different cams towards the same ends and would like comments on that. E.g. I cannot even get info about the effective length of cams (from batten "hilt" to mast) and even info about availability of cams is hard to get.

Looks like Simmer and SailLoft have similar bend curves www.unifiber.net/unifiber-masts-selector-2019-v1

You may want to post a pic of your sail rigged in case it's something that the more experienced windsurfers here can see. What a big luff sleeve looks like on the beach may differ from how it looks on the water. You also have the chance that as a used sail, some prior owner replaced battens, filed down cams, etc.

You won't likely find any data on cams, etc because the sailmaker is going to assume that you use the recommended mast(s) especially for a race sail. If you have the right mast, it should fit. If you use another mast, as Mark_australia said, results can and will be variable even if the bend curve seems to match or from the same brand.

Again, a pic or two can be super helpful for further advice.

There's a video around showing max mast bend. Similarly we can see the huge flex when landing back loops.

Masts can break from being underbuilt, defective, or possibly halfway inserted, but never because they're over downhauled.

Some race sails will have quite a low tension in the luff sleeve on the windward side, by design. It is better to go by the pressure that the cam has onto the mast and the ease of rotation. With the sail laying on the ground (cams pointing down too) you can push down at the end off the wide luff sleeve and see if you can get an substantial gap between the cams and the mast. If not then it is probably fine as it is. Of you put too much pressure on the cams you will compromise the batten rotation, while a too low pressure can in principle give a pressure point that wanders in the gust (put that would need to quite a way off, in order for that to happen). If it rotates fine then just sail as is now and see how it feels on the water. As said, a picture would help ;)

Many thanks for your valuable tips! They have cleared up 2 issues already: 1. I don't have to worry about breaking the mast by downhauling; and 2. per Unifiber charts, I note, in the 2019 version, that Simmer RDMs get 1 dot in CC and 2 in FT (FlexTop), whereas SailLoft RDMs (for which the sails are made) have all 3 dots in CC. That is probably a significant difference, taking Mark's point about small differences in curve characteristics making a big difference with cammed sails. Although Sail Loft's website says all sails are made to suit both RDMs and SDMs, it is reasonable to assume that a race sail like the Ultimate would be more oriented to the SDM (which is 1 dot closer to the Simmer's more FT curve from the Unifiber chart). Anyway, I take the point that the mast is certainly part of the problem. Another part (unmentioned in my original post) is that the sail has SDM cams and I only have RDM 400s (Simmer and Ezzy). I have tried the Ezzy, but it looks worse.
About the cams: Sail Loft understandably said the mismatch is a major problem, but the previous owner, perhaps disingenuously, says he used the exact same Simmer mast with the sail and it worked well (claiming that he didn't realise that the cams were SDM). I have tried North cams but without improvement. A key problem is that the middle 2 cams are very long (14 cm) and it would cost AUD280 to get the RDM cams from Germany (none in Australia, apparently) and they say that the RDMs are the same size as the SDMs. So probably little improvement for the money. I think I'll have to live with the SDMs.
Taking your suggestions, I am posting 2 photos of the sail below. They were taken 10 days ago and I've got the sail looking a bit better since then. I've increased the spacers from 17mm to 23mm (35%) on the second cam from bottom and similar percentages on #1 and #3. That is a lot more than the recommended maximum of 10mm, but it has reduced the folding problem without hindering the cam rotation. I might try another half spacer (2.5mm) but might start to hinder rotation with that. I should say that the folds on the windward side (as shown) are not so much the problem, but they are just as bad on the leeward side and sail theory suggests that is more of a problem. Anyway, I would be delighted if you would look at the photos and offer any further suggestions. Thanks again for those already offered.

Okay, the RDM mast explains the problem... ;)
Just add shims until the wrinkles improve, without hindering the rotation then. The test of pushing down on the sail to see if the cambers have a gap towards the mast is till a good one (with the boom attached).

It also looks like you can increase the batten tension in the battens near the boom.

Check that the rollers of the cams are pushing against the RDM mast, and not the cam itself as that would case additional wear on the mast and cams.

With most 4 Cam sails the top Cam is an RDM Cam as the mast is a smaller dia up there. If you compare it to the lower cams it should be longer. This should be the length you need to achieve with the lower 3 cams to be close to what you need. Too many Cam spacers putting the Cam close to the end of the batten won't be good so the correct length cams would be better.
A set of 3 rdm cams won't cost the earth here in Australia and most sail repairers should have a good selection.
I know Jesper at sailrepair WA sells tekcam cams used in simmer sails and probably has a bucket full of second hand ones of other brands.

Agree with Swindy ,Jesper at sailrepairs WA sell RDM CAMS made for simmers .he still has them on buy&sell 80$ for 4 .
get those and you might be laughing ..they are a longer cam so should get rid of your wrinkles ..maybe ask Jesper for a few spacer too..to get it set perfect .

Not all race sails will run a RDM cam at the top if using a RDM instead of SDM. KA for example will use 3 RDM cams on the bottom 3 positions and a SDM cam in the top position. This is because the mast diameter difference between SDM & RDM is the smallest at that point.

If you have a chance to get the RDM TekCams by Loftsails. they work perfekt in the Sailloft Hamburg Sails. I did that in my 6.3 and 5.6 Sailloft Missions. The TekCams have the perfect size!

About foreign masts in the Sailloft Sails. I found for SDM the Avanti Rival work well and lots of guys use Northsails/Duotones. With RDM the older Severne Redlines have been measured and showed the same bendcurve like the Saillofts. I tried it and it worked well.

Thanks for new comments. Very helpful!
Tardy & Swindy, I spoke to Jesper. He has the Simmer/Loft Sails Tekcams, but unfortunately none that fit my Sail Loft Hamburg sail.
Rukra, the Mission model must be different from my Ultimate race model, in which the 2 middle cams (either side of the boom opening) are 125mm from mast yoke to batten-hilt yoke, i.e. )-( . I'll see if I can live with the SDMs (as the previous owner did).
SurferKris, I'm using your 'pushing down' test and think I can put another spacer on the bottom cam. I've been tweaking the batten tension and eliminated most of the wrinkle aft of the luff sleeve. The mast seems to roll on the rollers and not against the cam-body.
Morts, The top cam is narrower, as you suggest and indeed that cam is good - no wrinkles.
In summary, I'll keep tweaking with spacers and batten tension and believe that I can get rid of most of the remaining wrinkle while maintaining batten rotation. I don't intend to be racing, or even trying for more than 30 knots. (Getting too old and damaged.) So I think the sail will perform reasonably well. I want to stay with an RDM-only kit, so will try other RDM-only cam-sails. I like the Loft Sails Switchblade (I've got a 6.3 and 7.8), so I might just keep an eye out for more of them. I also like the North S-type SL (I have a 7.3), which can take RDM, so there are other options if this one doesn't work out. Thanks for all your help!

Sorry if I missed it, what are the luff specs and extension + mast length. Looks like it's missing some downhaul?

I'm not an expert on cammed sails but happen to have sailed exactly one in the last twenty years: a Saiiloft Ultimate 5,6! It's from 2015 while yours looks younger, but still might follow the same rules.
A sailloft mast would be perfect, but accomplished speed sailors say that North/Duotone Masts work perfectly on them. Maybe you happen to know someone who can lend or sell you a 400/430 Platinum or Gold. I sailed it with a 400 SDM but I think a 430 would fit even better.
The wrinkles may or may not stem from the RDM/SDM combo and may or may not be an issue. My Ultimate had these wrinkles but not to the extent I see in your sail.
I go with Manuel in guessing that you need to apply more downhaul. I was surprised to see that I wasn't able to set up the sail properly with an ordinary extension. I'm no lightweight but only after buying a North Ratchet Extension I realised what the sail was supposed to look like. It's small, but it's a full on race sail that bends the mast quite brutally for someone only used to no cam sails.
Does it rotate well?
And isn't there someone who can 3d-print adapters to make SDM-cams suitable to an RDM-mast?

The luff specs are: downhaul 429 +/-1 (400 19 IMCS CC mast + 30 extension); outhaul 181 +/-2.
You are right that I might have had too little downhaul (using 28 extension). I have twice asked Sail Loft for guidance on sail 'twist-off', but zero response! I have had to use a downhaul winch to get even that 28, which gives me twist-off to about 50-60% max across from the leech. From what you both say, my 'normal' (mid-range) setting should be more. If you could give a max twist-off indication, that would be great. I assume that what I call twist-off is what you have spotted as insufficient in downhaul??

My two Freerace 3 cam Lofts both like the sail panel between top batten to 2nd to have the wrinkle all the way to the sleeve.
My North WARPS like it only 5/8th to mast sleeve.

^^^^ Loft, or Sail loft? Sounds like you said Loft Sails..... and this guy has Sail loft

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taveray said..
The luff specs are: downhaul 429 +/-1 (400 19 IMCS CC mast + 30 extension); outhaul 181 +/-2.
You are right that I might have had too little downhaul (using 28 extension). I have twice asked Sail Loft for guidance on sail 'twist-off', but zero response! I have had to use a downhaul winch to get even that 28, which gives me twist-off to about 50-60% max across from the leech. From what you both say, my 'normal' (mid-range) setting should be more. If you could give a max twist-off indication, that would be great. I assume that what I call twist-off is what you have spotted as insufficient in downhaul??

Does your extensions start at zero? On soooo many there is a couple cm 'missing' even with the pulleys touching so setting it at 30 is not giving you an actual 30. Then with a slightly different mast it may been and extra cm (or less) but you could have been missing 3or 4 cm downhaul which would be pretty significant

You are correct, Mark.

My two cents worth ,
To me it looks like it needs more downhaul . On the second panel down , the floppyness should be at least 70 -80% across to the mast . In the pic its only about half way across . The third panel down , at least 60 % . The leech looseness should at least go down to the second batten above the boom . Race sails don't use much outhaul . While sailing the sail should lightly touch the boom .
.A good way to check if the mast is the correct curve is to pull enough downhaul to get the wrinkles right . then check the tightness of the luff pocket against the front of the mast at the boom cutout . it should not be tight or have more than a couple mm gap . It should easily spin when you grab it with your hand and rotate. If the mast is too hard there will be big a gap . if it is too soft the luff pocket will be tight against the mast .
The mast may be wrong and then it just wont work no matter what you do .
Tighten the battens to remove wrinkles on the outside curve of the sail . The bottom three should be quite tight , the next couple medium tight and the top couple quite loose , just getting rid of most wrinkles . The inside will always have some wrinkles on the luff panel .
Then play with cam spacer length .

I agree - and now upon reflection:
(1) the previous owner reckons it works on this mast
(2) and you don't have enough downhaul

I think you need to put everything back the way it was and downhaul as Imax suggests. Plus, pic of your extension may help, as I said on may the numbers are not quite what you actually get

If you are not already using one, downhaul with a winch might make it easier to see what is going on.

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taveray said..
I like the Loft Sails Switchblade (I've got a 6.3 and 7.8), so I might just keep an eye out for more of them.

Keep an eye out for Loft Racing Blades, too. The Switchblades are nice, but the Racing Blades are even nicer, and work well on RDMs. They come with both RDM and SDM spacers.

Have you tried tensioning the batten? and yes sail has nowhere near enough downhaul, pic of 2018 sail notice leach, looks like the pics were taken at Beachport caravan park cabins

Its a Patrik designed sail so either ask Patrik or contact SailLoft. I think that Patrik stopped designing in2019 and brought his own sails out. Premo in WA was selling these sails and could likely have spares or even the correct mast at a great price.

Thanks again, gentlemen.
LeeD, I take your point to be that the twist-off varies greatly between brands (and models?).
Mark, I have old chinook carbon extensions. The numbering starts at 6, so I set the ferrule there then measure down 6cm and put a big mark there, so I know where zero is, then I I haul the sail down until the bottom of the sail pulleys is just level with my mark. (I have long assumed that the bottom of the pulleys is the correct thing to line up with. Is that the case?)
Numerous commentators on Downhaul: I usually set the extension to the mid-point. In this case, that is 429 (+/-1). The Chinooks have about 2cm more downhaul space after that. That's why I have been setting it to 428 (so I can pull down to 430), but I'll go back to setting at 430 thanks to the unanimous advice that I need more downhaul, then I'll be able to pull down to 432 if required. As mentioned above, I use a winch to get even to where I've been setting it, so will continue to need that. Choco's pic shows the twist-off touching the first orange tape in 2nd panel and top of 3rd, which would be close to 80% of leech to mast-front, so that's about where I'll aim for. Quite a bit more than before, so it might also sort the wrinkle problem. I'm heading for Boggy Lake (inlet on north shore of Lake Alexandrina) and expect enough wind to try it out, so I'll keep y'all posted on progress!
BSN101, I've googled Premo Perth WA, but can't find him/them. Do you have contact details?
boardsurfr, I'll certainly keep an eye out for Racing Blades, even though I'm not into racing.

Just one more thing , printed figures can be all over the place especially if your mismatching .
What I would do is add another 8 cm or so to your extension . Pull down until wrinkles look right . It's a visual thing and this is what you should set your sail to the first time .
Note how much gap you have between the pulleys and then minus that on the extension and then add 2 cm on the extension , you may want a little more downhaul room if it gets really windy .Remember this setting . And not the numbers printed on anything . Once you have established this you can then rig to the new numbers .

Sail Loft masts in the Buy &Sell accessories. Refine search to WA and 4 pages in.

To me the downhaul looks about right, certainly close enough in order to take out and sail with (if the rotation is okay). The low tension in the luff sleeve will not go away with more downhaul.

A 5.6 sails will not show as much loose leach as the later posted image of the 7.8 size, and to me it is difficult to say how much downhaul one will need by simply looking at the shape on land. So sail it and check how it feels, if it feels heavy and/or pulls hard in the hard but doesn't feel quick enough, then add a little more downhaul (in steps of about 1cm or less) and sail it again.

An adjustable outhaul (while sailing) is really helpful, the power is tuned with the outhaul once you have found the correct downhaul setting.

Second and third, and fourth using a down haul winch while watching the change in the sail, and as mentioned realize the factory numbers may be off, have an Aerotech Freespeed 8.0 that just looked bad with specified down haul range, finally added ~2-4 cm more downhaul and then it looked perfect. Steve from Aerotech told me that the printed range is not always right on due to variabilities between design and production.