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KevinDo
Joined: 02 Jul 2012 Posts: 426 Location: Cabrillo Inside
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Posted: Wed Apr 17, 2013 8:34 pm Post subject: |
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spennie wrote: | All right now everyone, think hard: HOW did you learn these theories? Seriously, who told you? A very good windsurfer, perhaps a pro? A shop owner? A fin maker? That guy who dulls his fins to protect his feet from cuts? The guy who cuts out his own freestyle fins, who rarely sails over 15 mph?
Sorry to get so snarky, but the endless unsubstatiated claims on this forum get to me after a while. I don't claim to be the all-knowing guru of all things windsurfer, that's ISOBARS, but I've done a lot of personal testing and experimenting over the last 23 years of sailing, and I know what actually works and what is basically wives' tales.
However, since I'm NOT infallible, I sat down with someone who could give me some serious scientific input on this subject, Dr Clint Harper. I have the good fortune to work at Moorpark College here in SoCal, where Dr. Harper is the chair of the Physics dept., and a sailboat owner (that's his latest boat in the picture).
I sat down with Dr. Harper today, and discussed the various aspects of this discussion. The short version is: Sand your hull if you want to, keep your fins smooth. Some of the stuff in this thread is accurate, but mostly it's just stuff somebody heard from someone they consider believable. I sometimes do that, but this is one subject I'm very mental about, as I sail mostly slalom, and love to speed sail (went 40 mph. a couple times). Sanding your hull is scientifically proven to work at sailboat speeds, but my feeling is how much will you gain, 1/2 mph? I'm not on the World Cup tour, so would rather have the extra epoxy on there.
Sanding your fin could cause the laminar flow to detach, which leads to spinout.
If you wish to dispute my assertions, please refer to the photograph, and make sure your source of infomation has a PhD (or better) in physics, and owns their own sailboat. |
Sooo...don't sand the board and the fins correct? |
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spennie
Joined: 13 Oct 1995 Posts: 975 Location: Thousand Oaks, CA
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Posted: Wed Apr 17, 2013 8:37 pm Post subject: |
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KevinDo: It's in there - Sand your board if you want to, but not your fins. _________________ Spennie the Wind Junkie
www.WindJunkie.net |
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U2U2U2
Joined: 06 Jul 2001 Posts: 5467 Location: Shipsterns Bluff, Tasmania. Colorado
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Posted: Wed Apr 17, 2013 9:05 pm Post subject: |
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some of the replys on this thread are fricking hilarious
1% this 5% that... what Journal/ Scientific Study are your making quotes from ?
Some think that shark skin being rough is the way to go, let me know which fin feels like that _________________ K4 fins
4Boards....May the fours be with you
http://www.k4fins.com/fins.html
http://4boards.co.uk/ |
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windward1
Joined: 18 Jun 2000 Posts: 1400
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Posted: Wed Apr 17, 2013 10:14 pm Post subject: :) |
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Now let's see......do I want my board and/or fin to have shark skin or dolphin skin. H'mmmmm....which is faster a dolphin or a shark? |
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U2U2U2
Joined: 06 Jul 2001 Posts: 5467 Location: Shipsterns Bluff, Tasmania. Colorado
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Posted: Thu Apr 18, 2013 8:09 am Post subject: |
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Most dolphins are faster than the average shark. However some sharks are much faster. The blue shark is a very fast shark with speed bursts recorded over 40 mph. And the fastest shark the short finned mako shark is the fastest, with speeds spurting over 60 mph.
more than 1 answer :
While some sources claim that both dolphins and sharks can swim at speeds of over 60 mph, these reports are few and far between. Most experts agree that the top speed of some shark species is about 30mph, while dolphins most dolphins can only get up to 20mph.
as seen ::
No scientific research actually shows that dolphins are faster then sharks for one reason. They can swim about 24 miles an hour next to a boat for ten to thirty minutes which a shark could only swim for a short amount of time to catch it's food. It's like a speed boost. So dolphins are faster then sharks! _________________ K4 fins
4Boards....May the fours be with you
http://www.k4fins.com/fins.html
http://4boards.co.uk/ |
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spennie
Joined: 13 Oct 1995 Posts: 975 Location: Thousand Oaks, CA
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Posted: Thu Apr 18, 2013 10:30 am Post subject: |
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Let's see, dolphins are smart, and sharks are badass, so if you combine them you'll be like me, a smartass! _________________ Spennie the Wind Junkie
www.WindJunkie.net |
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windward1
Joined: 18 Jun 2000 Posts: 1400
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Posted: Thu Apr 18, 2013 11:03 am Post subject: |
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But how smooth is your skin, Spennie? |
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spennie
Joined: 13 Oct 1995 Posts: 975 Location: Thousand Oaks, CA
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Posted: Thu Apr 18, 2013 11:33 am Post subject: |
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Like a baby's behind, but I don't swing that way, sorry. _________________ Spennie the Wind Junkie
www.WindJunkie.net |
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windward1
Joined: 18 Jun 2000 Posts: 1400
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Posted: Thu Apr 18, 2013 12:31 pm Post subject: |
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Me neither. Just trying to find out how slick a smartass you were . '' |
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U2U2U2
Joined: 06 Jul 2001 Posts: 5467 Location: Shipsterns Bluff, Tasmania. Colorado
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Posted: Thu Apr 18, 2013 1:55 pm Post subject: |
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update if you Professors come to a satisfactory consensus of opinion. I just finished packing the Van for a month on Hatteras, I need a beer..or 3
figure out how to become more minimalist.....in sails boards fins _________________ K4 fins
4Boards....May the fours be with you
http://www.k4fins.com/fins.html
http://4boards.co.uk/ |
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