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kaletor
Joined: 27 Jun 2007 Posts: 12 Location: SF Bay Area
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Posted: Sun Apr 21, 2013 12:06 pm Post subject: Mast extension questions |
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Hi,
I have two questions about mast extensions. Here is the gear I have:
Masts: 400 and 430 Skinny 91% Carbon (NP)
Luff dimensions of 3 sails I use: 414(4.9), 430(5.4), 466(6.3)
Mast extension: Chinook 38cm Aluminum
It is convenient to use a single extension for all of my sails.. Having said that:
1) Are there any issues(mast flexibility maybe?) with using a 38cm extension when I use my 430 mast with my mid sized sail(luff=430)? Should I use a shorter extension so the mast can flex more?
2) Is it a good idea to use an aluminum extension with carbon masts?
I am an intermediate windsurfer so I would not want to spend ~$100 for marginal gains but I am wondering if the above have any significant effect..
Thanks! |
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coachg
Joined: 10 Sep 2000 Posts: 3549
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Posted: Sun Apr 21, 2013 12:28 pm Post subject: |
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Aluminum’s fine and it just depends on how your 5.4 rigs on the 430 with 30+ cm extension suck up into the mast. I had to buy a short skinny extension because the long extension shoved up into the base of the mast made the lower part of the mast so stiff that the extension pulleys wouldn’t line up properly with the sail pulleys and they kept slipping off and binding while trying to down haul. If you have no problem rigging it, then don’t bother with another extension. Only get another extension if you have problems rigging the 5.4 or you need to have two separate sails rigged.
Coachg |
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adywind
Joined: 08 Jan 2012 Posts: 665
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Posted: Sun Apr 21, 2013 12:29 pm Post subject: |
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Find out what size mast is recommended for the 5.4. If they recommend a 430 mast and if the sail has an adjustable luff top /as I'm sure the case is/, release it some so the mast protrudes from the top and you have enough room at the foot for the extension and 3 fingers of slack for min/ max downhaul adjustment. If the luff top is fixed then use the 400 mast with long extension /the worse case scenario /.
It's Perfectly fine to use aluminum extension with a carbon mast.
In general smaller size sails allow for more fluctuation from manufacturers recommendations, so don't be afraid to experiment. As long as the rig looks and feels fine you are good to go. |
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swchandler
Joined: 08 Nov 1993 Posts: 10588
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Posted: Sun Apr 21, 2013 2:26 pm Post subject: |
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Coachg brought up an important point, the ability to rig a second sail. Also, it would be good to have a backup extension should you have a failure or problem with your primary extension. Extensions are pretty dependable, but they still can break or suffer a component failure. Lastly, it's not a good idea to insert an extension with better than 50cm into a mast because it puts a lot of stress on the bottom of the mast, and it just might be extending a bit beyond the re-enforcement built into the mast. I would recommend buying a medium extension that will give you up to 28cm of boost. |
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isobars
Joined: 12 Dec 1999 Posts: 20935
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Posted: Sun Apr 21, 2013 7:58 pm Post subject: |
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If an extension sticks up into the mast far enough to affect mast stiffness (i.e., it binds when the mast is flexed), the mast is being point loaded and is much more likely to break at the base of the mast or the top of the extension.
Mike \m/ |
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PeconicPuffin
Joined: 07 Jun 2004 Posts: 1830
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Posted: Mon Apr 22, 2013 7:09 am Post subject: |
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Aluminum extensions with carbon masts are no problem at all.
In addition to the slight (but real) performance concern about having a long extension inside the mast, I invite you to consider that it's actually way more convenient to have more than one mast base extension. Setting aside the short term costs of buying them, anything you can do to reduce rigging time is a gift.
I have one extension set at "0" for all my sails that require no additional length, and separate extensions for all my other sails. It's very nice to simply grab the right extension and go. I built up to this over time...first I had one extension, then two (so I could keep two sails rigged), then two and a shorty (shorties are the least expensive, and rig all of your "extensionless" sails), etc.
.02 (okay more like $60 a pop, but your time may be worth it!) _________________ Michael
http://www.peconicpuffin.com |
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kaletor
Joined: 27 Jun 2007 Posts: 12 Location: SF Bay Area
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Posted: Tue Apr 23, 2013 10:11 pm Post subject: |
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Thanks guys! I'll start with a shorty for convenience and as a backup. Appreciate all the responses. |
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beaglebuddy
Joined: 10 Feb 2012 Posts: 1120
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Posted: Wed Apr 24, 2013 2:38 am Post subject: |
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I've seen more bent aluminum extensions or snapped carbon extensions than broken masts. |
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PeconicPuffin
Joined: 07 Jun 2004 Posts: 1830
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Posted: Wed Apr 24, 2013 11:26 am Post subject: |
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kaletor wrote: | I'll start with a shorty for convenience and as a backup. |
Good decision! You won't regret it. _________________ Michael
http://www.peconicpuffin.com |
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swchandler
Joined: 08 Nov 1993 Posts: 10588
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Posted: Wed Apr 24, 2013 3:12 pm Post subject: |
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"I've seen more bent aluminum extensions or snapped carbon extensions than broken masts."
In my 28 years of windsurfing, I've never broken or bent a mast extension. I wish I could say the same about masts. |
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