How windsurfing fins work

adywind · Joined: 08 Jan 2012 Posts: 665

We have started this debate on another tread which was not appropriate, so I'm opening a new one specifically on this topic. I am not able to explain it scientificly, I just always considered the lifting effect of the fin as a result of creating different pressures in wich the object that creates them Is being pushed towards the lesser pressure which is windward and up in our case and since it lifts the tail of the board we the simple Earthlings call it lifting. Now I'll let the experts explain in this article and btw they also call it a lift:
http://www.windsport.com/gear_article?news_id=3

dllee · Joined: 03 Jul 2009 Posts: 5329 Location: East Bay

Just try windsurfing without a fin, with a too small fin, and with a too big fin, and you'd know.

U2U2U2 · Posted: Fri Dec 05, 2014 3:46 pm Post subject:

the Windsport article was written in 2008, fin systems have changed too include a QUAD now, which speed reading Derriks words I saw no reference to, his multi fin character descriptions leave much to the imagination.

Understanding how fins work, only presents a portion of what you need to glean to pick the set that is the best for you, dynamic picture on the water cause it changes.

I disagree with all he said on asymmetrical fins. And toe in was not even suggested .

He is one of the more knowledgeable and better sailors I have seen, ever.

adywind · Joined: 08 Jan 2012 Posts: 665

U2, the debate was simply about the regular single fin: does it create a lift or not . The article clearly answers that question I believe. The title is confusing I'm sorry about that Embarassed

dllee · Joined: 03 Jul 2009 Posts: 5329 Location: East Bay

I'm no scientist, but I know bigger means more lift, especially underpowered, and smaller means less lift, in almost all conditions.
Longer lifts the windward rail.
Shorter allows you to control the rails even overpowered.
But, what do you want to know, or is this an exercise in theory and science?

U2U2U2 · Posted: Sat Dec 06, 2014 12:10 am Post subject:

well I guess I know not what the question is either.

Do fins have lift ? Unqualified yes.

Since the Windsport article has a few paragraphs, maybe you meant as reference just the first one" How a Fin Provides Lift"

jingebritsen · Joined: 21 Aug 2002 Posts: 3371

fins also have drag. in lots of situations, lift to drag can become dysfunctional.

isobars · Joined: 12 Dec 1999 Posts: 20935

Yup. A flat plate at a positive angle of attack produces lift, but its drag renders it useless for our purposes. Foiling it, even symmetrically, lowers the drag and lets it work as intended.

U2U2U2 · Posted: Sat Dec 06, 2014 10:41 am Post subject:

flaherty · Joined: 01 May 1997 Posts: 437

We can have an "intervention" in Hatteras. Or just goto FA (finaholics anon) , they must have one in Colorado. Take it from me, you need help!