Lowest batten doesn't pop into right shape for wind direction

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HamdiD
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Joined: 10/08/2018 - 10:32
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Lowest batten doesn't pop into right shape for wind direction

I am new to windsurfing, using a 2nd hand board (KonaOne) and rig (about 8 yrs old, Aerotech 6.4 sail, powerex 60% carbon 460 mast). I have a couple issues, in order of priority:
1. The lowest batten does not pop into correct shape for wind direction. Namely, after I tack, it flips to the other side of the mast but stays bulging towards the same direction it was (ie. into the wind after the turn) and I have to push on it by hand for the sail to have the right curvature for the wind direction. I have downhauled a lot (see issue #2) and have slack on the upper sections of the sail and the battens are clear off the mast. I have played with batten tension, lowering to the point of seeing clear wrinkles on the sail around the batten, then tightened just until they disappear. Granted, it might not help that I am going out on light winds due to being new. Any thoughts? Would outhaul impact this (I have been setting it pretty tight, being new and not wanting to catch a lot of wind)? Could something be wrong with the batten? If so, how does one go about replacing?

2. The sail's luft length is printed as 461-464. With the 460 mast, that would mean bottom position of extension. However, in that position, I could not downhaul nearly enough - pulleys on sail hitting pulleys on extension with a very tight leech all the way up, battens way past the mast (can't flip). I had to put the extension much higher to be able to get visual indications of correct downhaul, likely running the mast+extension at about 468-470. Is this unusual or indication of something wrong?

Any inputs would be appreciated.

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cody.stubbz
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Joined: 11/09/2018 - 10:33
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Re: Lowest batten doesn't pop into right shape for wind...

HamdiD,

your problems aren't uncommon. without seeing photos of the sail rigged i have these thoughts:

-used sails that age often develop "memory" in the lower battens from being over-tensioned and rolled up...not anything you've done wrong it's just age and previous owners
-yes light winds sometimes aren't enough to rotate strong lower battens
-don't crank on the outhaul just to get one batten to rotate...Aerotech rigs are not happy when outhauled too much
-yes you can purchase replacement battens, your local shop probably has some and the Aerotech loft is just south of you in Florida...if you really get into this sport (which we all hope you do!) you'll end up with your own stash of spares eventually, haha
-a sail's printed luff and what you actually have to rig it at can sometimes be different...not only do sails stretch slightly over time but no two extension brands are exactly alike...it's annoying but true. the extension you're using might be different than the one the brand used during development

can you post a pic of the rigged sail? that might help

source: i'm a fan of Aerotech...they haven't let me down yet

-stubbz

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Marek
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Joined: 11/27/2004 - 09:05
Posts: 194
Re: Lowest batten doesn't pop into right shape for wind...

Hi and welcome to the site/sport,

Regarding your issues.
Some sail specifications were not that exact, also there are some differences in mast lengths (I've seen difference up to 1.5 cm on current RMD masts between brands) ....although from what you describe it the difference is more.
Other potential issues:
Have you measured the mast to see if maybe someone cut off a few cm from the bottom?
Is the sail head adjustable?

Regarding the out-haul, I would not tension it that much. The sail will not work great in low winds if it is over out hauled.

Batten not flipping...more wind will solve this, or a quick pump of the sail. But why you have this problem, just some thoughts:
- older sail maybe, I've had some sails that were prone to this (but probably at least 15 years ago)
- wrong curve/flex/stiffness of mast for this sail
- Batten got a permanent bend in it from being rolled up improperly and stored for long time...maybe?

Maybe William or Randy may have other thoughts on this.

Marek

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HamdiD
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Joined: 10/08/2018 - 10:32
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Re: Lowest batten doesn't pop into right shape for wind...

Marek and Cody,
Thanks for your very quick and detailed responses.
I will take and post a pic of the rig over the weekend.
I will also try outhauling less, see if that helps.
Otherwise, I should probably try replacing that batten. Need to first figure out how to take it out and get in touch with Aerotech or a shop that might have the type/size.

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cody.stubbz
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Re: Lowest batten doesn't pop into right shape for wind...
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FoilDodo
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Joined: 03/19/2008 - 23:50
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Re: Lowest batten doesn't pop into right shape for wind...

Cody’s the man when it comes to all things Aerotech or Kona. Seems like many sails have this issue in light wind. Often have to kick it to force rotation.

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webguy
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Joined: 12/31/2000 - 22:01
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Re: Lowest batten doesn't pop into right shape for wind...

First of all, congrats on grabbing a good board to get started on. The ratio of success goes way up. Also, thanks for reaching out to us - the people who have responded so far are excellent windsurfers which is one of the things that make our little neighborhood a pretty cool place. Good

Just to make sure that I'm reading you correctly:
1) The sail seems to take more downhaul than the printed specs
2) The bottom batten takes on a funny curve when downhauled so the leech is floppy

As others have mentioned, sometimes sails stretch just a touch over time. Sometimes, the factory just gets the specs wrong - typo, miscommunication with the designer, the guy/gal on the assembly line missed stitching a panel or two. Not often but it does happen. For your purposes, none of this affects the sail, just where you set the downhaul. Also, most of us will set the downhaul a couple of cm beyond the measurement because with the angle of the lines into the pulleys, it's often difficult and inefficient to downhaul pulley to pulley. btw, does the sail call for a 460 mast? A lot of mid 6s (and some 7.0s) will rig on 430s.

As to the problematic batten, does it do this on both sides or does it seem to have a set in it that makes one side exhibit the behavior more than the other? On some sails, over downhauling it will cause the bottom batten to take on an S shape. If it's doing this equally on both sides, The easiest thing to do is take it out and give it an eye ball and also see if it seems symmetrical.

I'm more suspicious of the mast. Powerex generally made (the label is owned by someone else now) good masts but there's a chance the bend isn't right or that the sail might set better on a 430 even if it calls for a 460. Is your powerex an SDM or RDM (standard or skinny)? More recent non-cammed sails also seem to set better on an rdm.

And, as has been mentioned, a picture is worth a thousand words. Biggrin

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Randy
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Joined: 05/05/2002 - 10:38
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Re: Lowest batten doesn't pop into right shape for wind...

The sail numbers can be really close or really off so don't ignore them but go by how it looks and feels. I just kick the sail if it doesn't rotate.

Welcome to Atlanta, where windsport dreams come true.

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HamdiD
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Joined: 10/08/2018 - 10:32
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Re: Lowest batten doesn't pop into right shape for wind...

Thanks again for the welcoming to the sport wishes and comments on my batten/sail issues.
I believe the batten not popping to the right shape (concave/convex) exhibits itself on both sides as I think I had to push on it after each turn. I should take out the batten and examine - if I can figure out how to do so. I don't know if it's just backing off the screw all the way?
I am worried it could be the mast-sail compatibility (at this point anyway); hope not. that would be a bigger issue I suppose. The sail calls for 460 I believe and the mast is SDM. I really wanted an RDM but didn't work out that way with this used set up; hope I don't regret not going for a new set up to avoid any such issues. I will take out the batten to examine, will outhaul less, and take pics this weekend.

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Marek
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Re: Lowest batten doesn't pop into right shape for wind...

I wouldn’t stress about it too much. Just get as much water time as you can.

Marek

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webguy
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Joined: 12/31/2000 - 22:01
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Re: Lowest batten doesn't pop into right shape for wind...

I'm an idiot for not asking the simple question: which model Aerotech sail is it? (and can you find a picture of it on the internet to verify the approx year?)

In the meantime, Marek is 100% right. Get the sail wet and have fun!

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cp
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Re: Lowest batten doesn't pop into right shape for wind...

I've had sails that tended to do this - can be a little irritating, but only tends to be a problem in very light winds, and even then can usually be corrected by a well timed, sharp pump of the sail. If that fails, you can always kick it.

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gene_mathis
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Joined: 05/17/2002 - 05:00
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Re: Lowest batten doesn't pop into right shape for wind...

You do need wind for a sail to pop around. To help it to rotate, when popping it, pull harder with the back hand, I dont know why this works but it does.

Also, the specs printed on the sails can be right on (Neil Prydes used to say +/- 2 cm,) but with older Aerotechs, it should have said +/- 2 Inches.

Also, I have a bunch of spare battens, FREE.

Gene

Gene Mathis

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HamdiD
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Joined: 10/08/2018 - 10:32
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Re: Lowest batten doesn't pop into right shape for wind...

It is aero tech AirX, mast is powerex 460, 60%. I was told both are 8 yes old. I will get pics tomorrow and try some of the suggestions, though it will be at low wind. If the batten is permanently bowed, i might take Gene on his generous offer, thanks!

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webguy
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Re: Lowest batten doesn't pop into right shape for wind...

http://www.aerotechsails.com/2009-10air.php

2009-10 specs
Size Luff (cm) Boom (cm) Battens Cams Mast Weight (kg)
6.4 466-470* 184-187 5 0 460/25 4.32

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