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Old 22nd May 2009, 05:14 PM   #21
Farlo
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Evidence is that windsurfers are not waxing their boards, and theories which suggest that polished is best are not relevant for planning hulls, unless you find one.
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Old 22nd May 2009, 05:24 PM   #22
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Quote:
Originally Posted by Farlo View Post
Evidence is that windsurfers are not waxing their boards, and theories which suggest that polished is best are not relevant for planning hulls, unless you find one.
HAHAHA
hulls or fins?
if the only evidence is that windsurfers arent doing it then you have no argument.
plenty of arguments put forward in favour of polishing, referenced as well. The arguments in favour of sanding seem spurious so far- unreferenced. It would seem that the sanded is better theory is based in lala land as opposed to argued reason.
If you have an argument that suggests sanding is better than polishing can you explain it?
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Old 22nd May 2009, 06:03 PM   #23
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Takes less time. Windsurfers are lazy. Your references are not relevant for planning hulls. And you'd better keep water stuck to your fin to limit spin-out, friction drag being of second order.
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Old 22nd May 2009, 09:34 PM   #24
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Interesting discussion.

The only theory I can support is the sanding of fins to minimize spin out. Faster or slower I can't say, but there does seem to be better control with sanded fins (formula and slalom).

When fins do get dinged or scraped, I sand to remove the abrasions. A half polished, half sanded fin doesn't sound like a good thing, so if my fins come unsanded (rarely), then they get sanded before use.

Regarding boards, I sail them the way the come, some polished, some with very fine sanding. I can't tell any difference.

What do the America's Cup boats do. If anyone has the money to research the fastest hulls, it's them. Polished? Sanded?
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Old 22nd May 2009, 11:38 PM   #25
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Here is what Carbonart advice you to do every now and then with your board to maintain top performance. I wonder if even the top PWA sailors do this, or do they hand their boards in to some bottom finish guru ?

http://www.carbonartwindsurf.com/Per...ce/Maintenance
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Old 23rd May 2009, 12:30 AM   #26
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Clean surface is fast surface... not bad. Let's take it this way: planning is due to hydrodynamic lift. Water is pushed down as the board goes forward. Flat or concave are more effcient than vee shapes because they trap water better. But air is also trapped with water. A wetted hull will roll over air bubbles with minimum interaction while a non wetted hull will stay in touch with air longer and "drag" the bubbles. However at some stage water comes in touch with this hull, otherwise it would not plane. The additional surface energy needs to be taken somewhere. As we can assume the water/air ratio under the hull to be consistent, this energy is given back somewhere. I tend to believe it causes additional spray. Does it make a significant difference? I'm not sure.

Last edited by Farlo; 23rd May 2009 at 12:38 AM.
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Old 23rd May 2009, 04:12 AM   #27
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Cool

Windsurfing is full of spsuedo scientists.
To my mind the original question was answered way back (in link)
Amazing how many sailors cant read !!!
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Old 23rd May 2009, 12:45 PM   #28
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What do you read in the link unregistered because it seems that you are the only one who is concluding that polished is definitely the best thing to do. NO one can conclude anything about it. It looks like you are the smartest one here. Maybe you can explain it to us.
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Old 23rd May 2009, 05:22 PM   #29
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Martin obviously crashed his fin on the way back to the carpark.

Go polish your fins and try. But make sure you bring some 600 paper to fix it afterwards. You will soon tire of the spontaneous spinouts.
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Old 23rd May 2009, 06:35 PM   #30
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martin crashed his fin first. Then he pushed it into the sand bank to remove the worst of the debris. then he caught a gust and went over 50 knots with a fin that was really lessed up.
Polished sanded? hehe dont think he cared!

so why is sanded good for a fin? why do you get bad stall? earlier in the thread i said about the reatachment of flow. it can be argued that sanded will be better rearwards on the chord in order to promote reatachment after the seperation bubble. Forwards of the seperation bubble polished will be good in order to delay seperation in the first place. Sanding is all about giving more friction for the water to stick to, good for a turblent flow section maybe? not so good for a lamina flow section?
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