I sail in light winds ( most of the time around 12 knts ) by choice and also by necessity. My board is a Bic 293, I weigh 85 kg and I am sort of intermediate. I use an Ezzy 7.5 and for the really light winds a Severne Focus 8.5., both RAF sails. The mast is a 75% carbon Gun Sails mast.
The problem I have had for quite sometime is that, even with the strong downhaul of a winch and an adequate outhaul, the mid-sail battens stick badly half way around the back of mast and they don?t come out as they should to allow swift rotation. I even have to push hard against the sail to have it rotate and not always successfully. This problem is most prominent with the Severne Focus 8.5.
What I found today while playing with the rigging of the Severne Focus 8.5 in my back-yard came close to an epiphany : I noticed that the luff sleeve is way much larger than the diameter of the mast. In fact, there is a 3 inch excess fabric between the end of the battens in their pockets and the mast inside the sleeve ! It is a sort of fabric slack, which is pushed away by the batten tension towards the rear of the mast and almost wraps around it! The only way to get the batten forward, close to the mast and not half way back would be to narrow the luff sleeve by sewing it longitudinally, so that the mast fits more snugly inside the luff and the battens get closer to it. I wouldn?t want to overdo the downhaul winching for fear of breaking the mast or ripping the sail.
Any comments or suggestions?

Thanks

Ittiandro

Picture help more than descriptions... got a pic of your epiphany?

I very strongly suspect lack of downhaul or outhaul making it look slack. Are you really setting it to spec?

Ezzy has typically been CC/constant curve - right smack in the middle
Severne Sails have typically been hard top
Gun Sails (and masts i presume) are constant curve - closer to Ezzy than Severne
the Severne is MORE mast specific than the Ezzy
the luff is about 490 on that sail and asks for a 460
if you are Franco from Montreal, you can pm me and we could try a MS 490/75 on that sail
MauiSails are closer to Severne than Gun
luff width just makes it easier to "shove" the mast up the sleeve without crinkling the sail !!

It would have to be a problem with the mast curve profile not being compatible with the sail.
The easiest way to fix it would be to get the recommended mast for that sail.
Definitely don't go trying to modify the sail to fit the mast you have because the finished product probably wont work.
When they design these sails they throw away dozens where the modifications they do make the sail worse.
You've only got one, so you don't have dozens to get it right.
That is, unless you've got one of the prototype sails they threw away because it didn't work properly.

Curve is more than likely wrong with that mast in the Severne - but surely not that wrong!
Even a NP on a Maui mast or vice versa would not have the 3" of "extra" width in the luff tube. That sounds like the mast is too straight ie: waaay under downhauled

Really wanna see pics cos I am having trouble picturing the floppy "extra" luff sleeve fabric

Maybe an extra long mast extension making the base of the mast too rigid?

wrong mast, with 30 cm xtension and not enuff outhaul
perhaps that would explain it ??

Simply, Not enough downhaul...

did an experiment today
have an old MS-2 no more cambers that i use as a go-to sail
had a similiar loose luff material on batten above boom
more outhaul helped more than more downhaul
was on the appropriate MS 490/75 mast

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mathew said..

Picture help more than descriptions... got a pic of your epiphany?

I'll send some pics as soon I'll recover the use of my left thumb temporarily disabled due to a deep cut while working around the house. I'll rig the sail again and show where the problem lies.It will take a few days.
It occurs to me, though, that I inadvertently rigged the 8.5 on my other 490 cm mast, instead of the usual 460. They are the same brand ( Gun Sails). They are both constant curvature and look almost identical, although the 490 is a 75% carbon, while the 460 is a 50%. May be this is the problem. Is it possible that the 490 was too long for the the 8.5 and the curvature was differently distributed, causing the batten to stick more?
From what I recall the problem was indeed less pronounced with the 460 , although the battens always stuck a bit and it took a lot of d/haul to free them and still the rotation was not as smooth as I hoped. I'll rig the sail on the 460 again and see if there is a difference.

Thanks for the comments


Francone

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mathew said..

Picture help more than descriptions... got a pic of your epiphany?

I'll send some pics as soon I'll recover the use of my left thumb temporarily disabled due to a deep cut while working around the house. I'll rig the sail again and show where the problem lies.It will take a few days.
It occurs to me, though, that I inadvertently rigged the 8.5 on my other 490 cm mast, instead of the usual 460. They are the same brand ( Gun Sails). They are both constant curvature and look almost identical, although the 490 is a 75% carbon, while the 460 is a 50%. May be this is the problem. Is it possible that the 490 was too long for the the 8.5 and the curvature was differently distributed, causing the batten to stick more?
From what I recall the problem was indeed less pronounced with the 460 , although the battens always stuck a bit and it took a lot of d/haul to free them and still the rotation was not as smooth as I hoped. I'll rig the sail on the 460 again and see if there is a difference.

Thanks for the comments


Francone

As indicated in my reply to Mathew, the problem MAY be ( I am not too sure) that the 490 mast was wrong for the 8.5, which I usually rig with a 460.
I keep hearing all over " not enough downhaul" ( or outhaul) as the probable reason. It could certainly be true if I downhauled by hand..But I do have a winch and in order to get those darned battens come out properly I can assure you that I am really winching a bit hard.. There probably is some more room and I could keep winching, but for how long, before it snaps? I wouldn't want it. I don't know if there is a " scientific" maximum bending tension value for the mast which I should use as a guideline and a tool to measure it.. But if I have to start getting involved with these technicalities and in this sort of gadgetry, which could be expensive, then I might as well give up windsurfing and go sailing on a small sailboat like a Topper...

Francone..

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Francone said..

As indicated in my reply to Mathew, the problem MAY be ( I am not too sure) that the 490 mast was wrong for the 8.5, which I usually rig with a 460.
I keep hearing all over " not enough downhaul" ( or outhaul) as the probable reason. It could certainly be true if I downhauled by hand..But I do have a winch and in order to get those darned battens come out properly I can assure you that I am really winching a bit hard.. There probably is some more room and I could keep winching, but for how long, before it snaps? I wouldn't want it. I don't know if there is a " scientific" maximum bending tension value for the mast which I should use as a guideline and a tool to measure it.. But if I have to start getting involved with these technicalities and in this sort of gadgetry, which could be expensive, then I might as well give up windsurfing and go sailing on a small sailboat like a Topper...

Francone..

Dont use a winch for the first 90% of the downhaul... if you are using a plain old windsurfing-winch, it will rotate the rope 90 deg. for every 360 deg rotation of the arm. ie: compare when you hand-wind a rope... ether you do the inside-outside thing, or you need to flick the end of the rope to get it to untangle. The only time you should use a winch, is when it is too hard to pull any further wrt. to ease-of-pull and/or causing a back injury... try using your harness and your legs (not your back).

Also, get some good rope... (I have seen lawn-mower-rope... wtf?) Good rope can make such a difference, that you may not need your winch. ie: compared to just about everything else in windsurfing, the rope is about the cheapest individual piece.

A few 90 deg. rotations is enough to turn a "good rope" into the crappy lawn-mower-rope.


As for the 490 vs 460... if you used any extension at all when using the 490, then you probably should be using the 490... as the 460 is likely to be too soft (all thing being equal, and you arn't below 60kg).

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Francone said..

But I do have a winch and in order to get those darned battens come out properly I can assure you that I am really winching a bit hard.. There probably is some more room and I could keep winching, but for how long, before it snaps? I wouldn't want it. I don't know if there is a " scientific" maximum bending tension value for the mast which I should use as a guideline and a tool to measure it..

I should mention, you wont break you mast *ever* by downhauling it... if it did break, then *more-than-likely* it would have broken on the water. ie: the shock-load caused by the interaction of the wind, your body and the water-state, will be about an order-of-magnitude higher than you could downhaul.

See the little numbers on the bottom of the sail, they are there to tell you how to rig sails, its quite simple really,

1.use the mast recommended for the sail, add the amount of extension needed to match the mast length number printed on sail, pull downhaul as far as it will go..

2. do the same with the boom..

3, attach sail to board..

4. go windsurfing..

It really is that easy. if the sail don't look right, the mast is wrong!!

Try to put a Datsun motor in a Ferrari, this also will probably not perform like it's made too..

^^ seen 700hp from a Datsun motor so there.

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pweedas said..

Maybe an extra long mast extension making the base of the mast too rigid?

I also thought about this. In fact I am using a 22 in. extension which goes about one ft inside the bottom of the mast. Somebody else commented on this, though, on another forum and said that the bottom part of the mast bends minimally anyway , if at all, so that one ft of mast extension inside it wouldn't make any difference..Actually,they say, the opposite would be the problem: too little extension inside the mast may cause breakage.
Maybe somebody else can comment on this...

Thanks

Francone

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Francone said..

I also thought about this. In fact I am using a 22 in. extension which goes about one ft inside the bottom of the mast. Somebody else commented on this, though, on another forum and said that the bottom part of the mast bends minimally anyway , if at all, so that one ft of mast extension inside it wouldn't make any difference..Actually,they say, the opposite would be the problem: too little extension inside the mast may cause breakage.
Maybe somebody else can comment on this...

It is true that it wont bend as much - this is usually due to the increased diameter of the bottom section wrt. the top section; a "large RDM" mast will likely have a very similar bend curve at the bottom as the top. It is possible that you can stiffen the bottom section (aka make it less bendy) by inserting a long mast-extension.

Not sure where you got "too little is bad" from...
- There is a zero-length base called a "cup", which essentially is only about 10cm long.
- Also, Chinook mast-extensions have a collar which has about 2.5cm of length; the remainder of the extension has reduced diameter so doesn't touch the inside of the mast.

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Mark _australia said..

I very strongly suspect lack of downhaul or outhaul making it look slack. Are you really setting it to spec?

You were right! It was not enough downhaul !
This time I tried to rig the Ezzy 7.5 first, but I wanted to go back to their rigging guide, which I had probably overlooked.. Here I discovered that for a correct downhaul, the second panel from the top of the sail ( between the 2nd and 3rd batten) must begin loosening up with a crease. I was far from that! In fact, in spite of all the hard cranking and some ..ominous squeaks coming from the mast (or the sail ), only the 1st panel of the sail was loose on my previous attempts ! So I kept downhauling further and further ( holding my breath!) until I hit the 2nd panel mark ( without breaking the mast!). After adjusting the outhaul, now the batten are finally free and the sail rotates well.

Keeping this in mind, I then got on rigging the Severne. The rigging was a lot better this time , but not quite as good as with the Ezzy. In fact, with the Severne Focus, in order to free the batten, I have to downhaul considerably more than with the Ezzy, to the point that almost half of the leech length becomes slightly loose, which I think is too much, because it may depower the sail a bit.

If I slacken the downhaul a bit, the leech does become more taut again, but then the batten begin to stick once more and the rotation becomes more sluggish, just as before.
I begin to think that this is really due to a mismatch between the mast and the sail. In fact, I discovered elsewhere on this Forum a sail-to-mast match chart: here the Severne sails show a RED color (incompatible) when matched with the Gun Sails masts. On the other hand, Ezzy sails show as compatible with Gun Sail masts , which seems to be borne out by my findings today.

Bottom line, now I know that I have to downhaul more!

Thank you for your comments

Francone