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does mast extension length inside the mast make a difference ?

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Created by joe windsurf Monday, 17 Jul 2017
joe windsurf
1078 posts
Monday , 17 Jul 2017 9:47AM
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many moons ago, I asked this question on the MauiSails forum
Barry was interested, but both he and the forum have disappeared ...
from MauiSails that is
.
if 10 cm of extension is suggested, is it best to use the minimum mast extension - like 12 cm ??
if 20 cm is called for, use a 28 cm extension ??
the plastic sleeve seems to be the piece holding extension to the mast
what's the point of having more inside - no sexual connotation intended

Tardy
1559 posts
Monday , 17 Jul 2017 10:14AM
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True Joe ...you don't need any longer .

i cut one of my 40's down ,now I have all the correct size mast for my sails ..just got in the way .hack saw

it is the strongest part of your mast ,

Stuthepirate
WA, 2997 posts
Monday , 17 Jul 2017 10:58AM
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Every Mast has it's perfect extension size.
Most masts assume they prefer the longest extension set point but the long term performance of the mast can suffer.
I wouldn't use an SDM extension on an RDM mast and Vice Versa as you're not going to get the desired performance from either.
There are also Mast and Cup arrangements and also Extensions with levers on the outside. Both until recent times haven't been well accepted in mainstream society but are becoming more common since the introduction of Kitesurfing

powersloshin
NSW, 824 posts
Monday , 17 Jul 2017 8:54PM
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I don't think it makes much difference, the last bottom part of the mast does not really bend. I have a pretty long one that sometimes have used at minimum extension and did not notice any problems or difference. Of course you need to make sure to have at least 12-15 cm of extension inside the mast, usually that section has no holes.

Mastbender
1355 posts
Tuesday , 18 Jul 2017 2:37AM
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Slightly off the subject, but only slightly.
I've never understood why the super long extensions are even on the market, they make no sense if used at or near the max extension, everything about it is wrong. Your mast is too short, you don't get the desired bend characteristics, and if it's an aluminum extension, it can easily bend. A waste of money for the cheap desire of convenience, which just hurts the rig's performance.

sl55
17 posts
Tuesday , 18 Jul 2017 4:36AM
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Select to expand quote
Mastbender said..
Slightly off the subject, but only slightly.
I've never understood why the super long extensions are even on the market, they make no sense if used at or near the max extension, everything about it is wrong. Your mast is too short, you don't get the desired bend characteristics, and if it's an aluminum extension, it can easily bend. A waste of money for the cheap desire of convenience, which just hurts the rig's performance.


Sometimes manufacturers (North, Avanti that I know of) recommend two mast sizes for their sails. North had their Type-S three sizes with one 460 cm mast. Avanti 8.4 Machine 3-4 can be rigged with 460 cm for overpowered conditions with softer feel and 490 cm for heavier sailors and/or light breezes. It works well as advertised, and I think it is a benefit- not a detriment.

joe windsurf
1078 posts
Wednesday , 19 Jul 2017 6:37AM
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agree with SL55
more extension just makes it softer
on the other hand ....
does 30+ cm extension inside the mast change the mast bend ?? really ??

joe windsurf
1078 posts
Thursday , 20 Jul 2017 6:57PM
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found an "old" discussion on the subject - SB forum:
.
www.star-board-windsurfing.com/forum/archive/index.php/t-3589.html

forceten
239 posts
Yesterday , 21 Jul 2017 10:36PM
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Select to expand quote
joe windsurf said..
agree with SL55
more extension just makes it softer
on the other hand ....
does 30+ cm extension inside the mast change the mast bend ?? really ??


You know how a mast bend curve is tested right..? Without typing for 10'. A weight is hung from the center, the difference in deflection is measured at 1/4 1/2 and 3/4, the difference is a measure in a percentage, from 1/2 to the others. This forms the basis for mast bend curve soft or hard, soft or hard on both bottom and top.

if you measure the same mast, with a extension installed will it change the curve? It will most assuredly change, how much?

joe windsurf
1078 posts
Today , 22 Jul 2017 1:15AM
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may also be a factor issue
if the mast is a 520 or 550 versus a 400
30 cm may be a bigger factor in bottom mast bend on the shorter mast ??

Mastbender
1355 posts
Today , 22 Jul 2017 3:09AM
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Select to expand quote
joe windsurf said..
agree with SL55
more extension just makes it softer
on the other hand ....
does 30+ cm extension inside the mast change the mast bend ?? really ??


It will make the top softer only, while making the bottom stiffer, which answers your question, yes, really.
Sound like you're considering buying only tall extensions, or have only tall extensions.
And as for sl55, the only advantage is to those sail makers, "buy our sails, you won't need so many masts".
I know,,,,,, I'm sounding like a purists, but the questions are purist in nature.



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