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PostPosted: Sat Feb 20, 2010 9:52 pm 
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Posted this on Wave forum and am repeating it here because I am wondering how a cracked batten pocket protector relates to sail's draft.

Cracked one of these:
Image

Crack's at the rivet at the top of the "H". Got part #80550005. New part has different location holes. Exact replacement part is #12480001, as per Matt.

Ok, fine. I got all that.

After doing some reading and poking around, several folks say that battens do the most in making sail shape/draft. My question is, is that true in your opinion? Do battens make sail shape more than downhaul or outhaul, etc?

The inward warp of this cracked batten protector was very visible when the wind was up. Could that have created additional draft in the sail that would have caused real problems flattening the sail and depowering? At first, I thought it wasn't that big a deal, but now am starting to wonder.

Did several quick searches here but found only one post about this.

Call this a groundhog post...


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PostPosted: Sun Feb 21, 2010 8:33 am 
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One cracked batten luff cap is unlikely to make any difference in performance (at least that you could tell).

Battens "fine tune" the shape of the sail. To a limited extent, they control draft position and depth.

Example:
I had some issues with upwind boat speed and pointing ability on my 14. I put the sail up, pulled the wrinkles out and took some pictures looking up from the boom. Imported the file to Photoshop and drew chord lines and positions of max draft. Turned out that I too much draft and it was too far forward. Turns out my battens were tapered too much.

The cure: bought two new bottom battens and moved all the battens up two positions. Photos and PhotoShop show the difference in the sail shape:
Image

Result: the boat goes upwind much better.


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PostPosted: Sun Feb 21, 2010 6:50 pm 
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JJ,
I have had very bad luck installing the stock batten protectors with a hand tool. Even taking them to a sailmaker. about half of them crack. I don't know if Hobie has a press to do them or what. I have never installed the stock protectors with screws, that may be the way to go, but I"m not sure. I would try to use the aftermarket ones if possible, the plastic is much more robust. I believe that most of the holes will line up. I use a torch to heat up a nail and burn through the cloth to make new holes. Measure once cut 3 times :wink: . You don't want to get it off.


That's an outstanding pic matt!! Tells a story, don't it?

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PostPosted: Sun Feb 21, 2010 9:05 pm 
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Thanks for tips, J. I had kinda assumed all what you say. I believe Matt mentioned using a flaring tool to lock the rivets. Was not looking forward to rivet pounding...

MB, that is an great pic. Thumbs up for a smart idea!

Actually the deep draft at the third batten up was the problem with the cracked pocket. The protector broke on a high wind day when the batten was left loose to flatten the sail. Left too loose, with the end barely in the protector, and pop.

Toward the end of the season, upwind seemed more difficult. And in heavy air, at some points, there was no way at all to depower -- sort of the opposite of the too-slow problem.

Things happen too fast on the water. Many have recommended setting up on land and looking at draft, leech location, etc. Using multiple images overlaid is pretty cool.


Last edited by JJ on Mon Feb 22, 2010 8:41 pm, edited 1 time in total.

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PostPosted: Sun Feb 21, 2010 9:30 pm 
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Whats the best way to put the new batten protector/pocket thing? I tried using a rivet tool but then all the rivets pulled through after the first sail.


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PostPosted: Sun Feb 21, 2010 11:13 pm 
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You set them with a tool like this, but like I said, I've broken a lot of protectors with it. The plastic is brittle.

Image

Hobie probably uses something like this:

Image

That's what my sail maker uses.

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PostPosted: Mon Feb 22, 2010 1:03 pm 
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They also make pocket protectors that use small nuts and bolts instead rivits. Great for field repairs.


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PostPosted: Mon Feb 22, 2010 1:09 pm 
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That's what part #80550005 is in the first post.

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PostPosted: Mon Feb 22, 2010 3:01 pm 
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Since I have to do one of these repairs soon, I've been doing a little research.

Came across this interesting page: http://home.earthlink.net/~billg4me/pinball/rivet/

Rivets and dies come from Hanson Rivet & Supply Co. - http://www.hansonrivet.com/

He made his own rivet press out of angle iron & some threaded rod:
Image

You can also adapt the dies to a drill press.


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PostPosted: Mon Feb 22, 2010 4:18 pm 
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That's it! I"m making one.

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PostPosted: Mon Feb 22, 2010 9:22 pm 
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IF screws and nuts install without risk (and put less stress on the protector and the sail) and IF screws and nuts work as well if not better than rivets, then why use rivets or spend time making those hot tools? Batten protector with screws and nuts look bullet-proof to me, if you know what I mean. Maybe Hobie could make the protector with screws and nuts...hint, hint, nudge, nudge, wink, wink, know what I mean, Matt, know what I mean?

The only other logical statement might be: IF you hadn't put additional holes in your sail, then it wouldn't have ripped, eh? I don't know...

Edit: That rivet press that that guy designed and had made is pretty neat. He must have had a nice drill press though to be able to drill out the all thread as neatly as he did.


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PostPosted: Tue Feb 23, 2010 5:14 am 
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As I recall there was a repair pocket available from perfect pocket that included brass screws.

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PostPosted: Tue Feb 23, 2010 5:45 am 
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The problems with the protector w/brass screws/nuts are:

- unless you use LocTite, the screws / nuts will come apart eventually.
- the brass corrodes in saltwater - turns green and stains the sail green.
- takes a long time to assemble (compared to setting rivets with the proper tools)
- has only 4 connections (as opposed to 5 on the OEM protector)

From Hobie Cat's standpoint, I can see why they do what they do - the OEM protector is easy and quick for them to assemble because they have the volume to justify the proper tooling. The aluminum semi-tubular rivets don't corrode and don't come apart, so the vast majority of owners never have to deal with any issues relating to them.


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PostPosted: Tue Feb 23, 2010 9:41 am 
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Little Wing wrote:
As I recall there was a repair pocket available from perfect pocket that included brass screws.


Part #80550005 has stainless screws but is the same one as perfect pocket basically but they changed the screws from brass to stainless in around 1989. The nuts fit into a 'slot' in the protector so they're flush when all said and done.

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PostPosted: Tue Feb 23, 2010 11:26 am 
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Yea I guess i'm getting old, I don't think perfect pocket is even in business any more. I dug through my parts and found a couple of the old buggers ,looks like I bought them back in 79.

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