Author Topic: glossy surface has substantially more drag than a matte one.  (Read 33184 times)

Paddlefit

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Re: glossy surface has substantially more drag than a matte one.
« Reply #45 on: January 10, 2011, 11:28:50 AM »
Does anyone have any more insight into this subject?  I had to do a repair to my board, and with the Cold Stroke Classic coming up this Saturday I was debating going to Home Depot and spending this friday sanding the bottom and rails of my board, as well as the blade of my paddle. 
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Fishman

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Re: glossy surface has substantially more drag than a matte one.
« Reply #46 on: May 11, 2012, 06:33:42 PM »
Lets  TEST this!!!

Boy, interesting info but most of this is very subjective and vague and may have zero relevance with our size boards and speeds. 

How about simple testing this. We should see if this really make a difference with SUPs.

All we need is a good scale, fishing line, a moving swim pool, a board and weight/sand bags. 

 I'm sure someone here has access to a "moving swim pool" (not sure what they are called, the kind where people swim in place)
Place the board in the pool, secure the board nose to the secured scale.
Turn the pool on to it to a average paddle speed.
Measure the drag. Then add weight 150 & 200lbs and ad measure. then experiment with sanding, waxing, soap... Then record the facts.

Anybody In Atlanta Ga have a Moving pool...?
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ObviousSup

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Re: glossy surface has substantially more drag than a matte one.
« Reply #47 on: May 12, 2012, 03:14:25 AM »
This stuff sounded pretty impressive
http://www.hydromer.com/seaslide_web/brochure_sealide.pdf

Then I noticed where in the drag test they noticed no improvement at 3 knots. If I could paddle at 20 knots the 17% reduction would sure be nice but I am not quite that fast.

I think I will just stick with my carnauba wax that I use on my other fiberglassed toy. After seeing the difference between how well water blows off a well waxed car vs a car that hasn't been waxed in ages I will go with wax. I don't need to trap water on the surface to act as a lubricant between the board and another solid surface (if I do I suspect I am doing something wrong). All I am concerned about is keeping my board looking nice and making water not stick to it. I suspect higher speeds that some boats attain might change things but with must me and a paddle I will not be seeing those speeds.

colas

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Re: glossy surface has substantially more drag than a matte one.
« Reply #48 on: May 12, 2012, 05:11:45 AM »
After reading this post, I 400-sanded both a windsurfing and a SUP board, and I say you can definitely feel a small difference in the transition from non-planing to planing, basically, your take offs are smoother, or on a wave when you go up the wave face, find  the trim line and put your weight forward, you feel the board "changing speed" more easily.

Other than this, I didnt feel any difference.

I sanded my paddle blade faces, but could not feel a difference there.

So I would say that for boards you enjoy the glide (longboards), it may be worth it if you are a nitpicker, but not if it destroy the looks of the board (visible wood, spray paint job on the blank, ...). On opaque white boards I would recommend it, for instance.

For racing. I guess only a controlled experiment would tell

PonoBill

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Re: glossy surface has substantially more drag than a matte one.
« Reply #49 on: May 12, 2012, 09:14:26 AM »
If you did manage to improve flow on a paddle face it would be a bad thing. Slip is just water flowing off the face and into the low pressure area behind the blade.

The hull sanding thing is pretty easy to test with a boat and an accurate scale and speedometer. You boom a weighted board off to the side to get it out of the turbulence and record force at a specific speed. I'd want to do the tests close together with several interspersed repeats to cancel out some of the environmental variables, but easy to so if someone really wanted to know. You could also do it in a lap pool with a winch (which is basically how a test pool works). A jet pool wouldn't work well, too much turbulence.
Foote 10'4X34", SIC 17.5 V1 hollow and an EPS one in Hood River. Foote 9'0" x 31", L41 8'8", 18' Speedboard, etc. etc.

 


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