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Thurston
Joined: 08 Jul 2013 Posts: 101
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Posted: Wed Dec 04, 2013 9:04 am Post subject: Couple of "beginner" questions |
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1. Where are you supposed to tie off or loop the bottom end of the uphaul line? I usually just loop it around the mast near the U-Joint but seems like there is probably a better way to do it.
2. What does the third number on a mast requirement mean? 460/25/25:
460 = 460 cm mast
25 = IMCS value (flexibility, higher number is stiffer)
25 = ??? |
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bred2shred
Joined: 02 May 2000 Posts: 989 Location: Jersey Shore
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Posted: Wed Dec 04, 2013 12:43 pm Post subject: |
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1) Rig your sail completely, then take the loop at the end of the uphaul and place it over your base extension so the extension passes through the loop and the uphaul is pulled up against the sail. Then connect your rig to your board/u-joint. The sail keeps the loop from being pulled up, the board keeps it from being pulled down. It's that simple.
2) Third number is probably the "MCS" number. MCS is the "Mast Check System" (the old system). IMCS is the "Indexed Mast Check System". IMCS basically normalizes all mast stiffness measurements to a 460 mast length so when you look at any mast, you get an apples to apples stiffness comparison. If your mast is older, it may have both MCS and IMCS numbers printed on it. In the example you gave 460/25/25, the third number is the MCS number. This makes sense since for a 460 mast, the MCS and IMCS numbers are always the same.
The important thing is to make sure the length and IMCS numbers match you sail's requirements.
sm |
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kmf
Joined: 02 Apr 2001 Posts: 503
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U2U2U2
Joined: 06 Jul 2001 Posts: 5467 Location: Shipsterns Bluff, Tasmania. Colorado
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Posted: Wed Dec 04, 2013 2:28 pm Post subject: |
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There are 4 sections, top left that deal with masts.
http://peterman.dk/start-windsurfing-samlet-gb-dk01.htm
the 2nd number you ask about is MCS, forget its there.
What you want to see what the mast really does is the percentage of deflection , that will give you a percentage of deflection at 1/4 & 3/4s length, subtract the 2 numbers,
ie 78 minus 65 = 13
is a constant curve flex top, Sail lofts design their sails with a mast bend curve, so it should be mast sail compatible, otherwise too stiff or too soft either top or bottom. there percentages are not always listed my the mast company, if requested most will supply them, they don't want you to have too much information, else you may purchase something else,
as well they think you are not smart enough to understand what they are, and in fact tell but a portion of the mast curve. percentage of carbon, its orientation AND MORE ALL ADD TO THE STIFFNESS.
uphaul line:
yes around the mast or the mast base, not much in the way of option. Some sails have a hole where the rope can be routed thru and then secured as above, Just need to do the job of being there and otta the way. _________________ K4 fins
4Boards....May the fours be with you
http://www.k4fins.com/fins.html
http://4boards.co.uk/ |
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