Shortening the batten for more leech tension better rotation

ittiandro · Joined: 22 Nov 2009 Posts: 294

Usually, on sails designed for shortboarding there is a limit to how much leech tension you can give: if you give them less DH ( = tighter leech) than what they are designed for, the battens will stick around/behind the mast and the sail will not rotate.

I was thinking that I could perhaps modify my sails for a tighter leech ( and less DH) without compromising the rotation, if I cut the 2 central battens by 1 or 2 cm, so that they move 1-2 cm forward and away from the mast, before DH, instead of hugging it too much. Right now, these batten, before DH, are almost half way along the mast circumference, towards the back. For proper rotation, I have to give a strong DH. Then the sail rotates perfectly, but the leech becomes too loose and the sail loses power in light winds...

My aim is to improve the light-winds performance of my Bic Core 293, by making do with the sails I have . I have an Ezzy Freeride 7.5, definitely too small for a shortboard in light winds..I also have a Severne Focus 8.5 , a bit better, but still not off the hook for subplaning.. Probably a 9.5 or larger will do, but I don’t want to go into such large sails because they become too heavy and hard to handle.

Can the batten be shortened as outlined before? Maybe this will affect the shape of the sail, but in the Ezzy sails the shape is already built in the central panels, so modifying the length of 2 batten by only 1-2 cm should not be a problem. Any comments on this?

Thanks Francone

coachg · Joined: 10 Sep 2000 Posts: 3550

I see where you are going with this but it won't work. The sleeve will be too long for the shorter batten. Before you destroy your battens try removing a longer one than replacing it with a shorter one from above. Now try to get the massive wrinkles out of your sail. No such luck? It is because the batten is too short for the sleeve.

My first thought is do you have the correct mast?

Coachg

carl · Joined: 25 Feb 1997 Posts: 2674 Location: SF bay area

I would email Ezzy directly and ask them this question, they are responsive
to questions like this, even older sails.
Tell them what brand, size
and model mast you are using with your Ezzy Freeride 7.5.

Severn may answer emails too, I have no experience with them.

manuel · Joined: 08 Oct 2007 Posts: 1158

Shortening the batten will have the same effect as releasing current batten tension. It'll create a bunch of wrinkles above and below the batten.

So you need to stitch a shorter batten pocket as well to make it work. Now a longer batten will draw a bigger pocket for the same tension so long as there's enough sail material. Usually found at the lower section of the sail.

Besides trying out different masts (bend curves, stiffness, lengths), different downhaul and outhaul, you can adjust batten tension slightly to produce more profile by adding tension.

With all that said, this should all be something of a last resort and besides regular sail tuning, mast track positioning, fin size and type, footstraps position, stance, all of those will give you a much wider range of tuning than playing with battens.

jingebritsen · Joined: 21 Aug 2002 Posts: 3371

planing applications? yucky handling and terrible top end.

non-planing? don't bother. like trying to put 20 kg of stuff in a 10kg bag, just not going to get one anywhere.

TheAdmiral · Joined: 27 Dec 2009 Posts: 43

Hi, For low winds I prefer cambered sails or sails that rig with a fuller profile. I have 2 Gaastra's that rig rather flat and powered up are very neutral and easy to sail but have no low wind power.My 6.0 matrix will not rotate without max downhaul and loose leach almost to the boom .I too have a Bic 293 I love to sail. Early to plane and for a wide ,long board gybes ok. I took out the dagger box and put a piece of plexi glass on the bottom to close up the slot and added Styrofoam to fill the cavity.My friend glassed in the bottom of his 293. In both cases the board planes much earlier ,sails faster, and is lighter.Really works. Mark

isobars · Joined: 12 Dec 1999 Posts: 20935

If the sail worked better with shorter battens, the sail designer would have built it that way. Adding more power up high generally compromises feel and handling ... part of the reason most people tune the Hucker for handling and cruising rather than big air.

U2U2U2

boardsurfr · Joined: 23 Aug 2001 Posts: 1266

adywind · Joined: 08 Jan 2012 Posts: 665

I've allready asked you what kind of mast you are using in another post of yours because I started getting suspicious and now everybody is aking you the same!
http://iwindsurf.com/forums/viewtopic.php?t=29380&postdays=0&postorder=asc&start=10
Will you be nice and give us an answer please because it awfully lot sounds like you are using the wrong mast!
Wait, let me guess! Ezzys use constant curve and can take a lot of masts just OK , so my guess is that you have a NP mast; a very stiff overall racing mast or some ancient fossil of unknown origin Laughing

And no, 7.5 is NOT too small for a light wind if you are 75 kg like me. I don't need anything bigger in the 10-20 mph wind speed even for the crapy lake conditions now that I become efficient enough. It's just that your 293 is heavy and slow. A big local guy was sailing it with a 7.5 Gator while I was overpowered at times with my AtomIQ 110 and a 5.8 and going circles around him . It was gusting up to 30mph on 12.25 when we got a generous gift of wind and temperature in the upper 40s here in Chicago , thank you Santa Smile

After we got in he came to check my board wondering how come I've been so much faster then him. Becouse you are riding a tanker , halloo! And I know that same guy has a 120 RRD FSW , go figure Confused