Removable center fin advice

Sailboarder · Joined: 10 Apr 2011 Posts: 656

Mmm... I posted a detailed answer that was lost in a digital black hole it seems...

To stay short, if banking the board is the first mean for turning while on the plane, changes in the sail position are more important and are used while planing too.

And when the sail is back at high speed, you are right that the COE is far back ( in fact over the water) but it doesnt bring the board upwind. You do that to counteract the increasing drag of the fin that couples with the forward lift of the sail to rotate the board downwind. Try to find Jim Drake's introduction to windsurf physics to see the detailed explanation.

cgoudie1 · Posted: Fri Sep 21, 2012 12:14 pm Post subject:

I'm going to have to mention that if your sail COE is behind your fin,
you're not in a stable circumstance, and are likely running too large a sail
for the board. For the best ride, you want your COE right over your
(rear) fin.

-Craig

Sailboarder · Joined: 10 Apr 2011 Posts: 656

No, it will be stable behind your fin. I am certain he didn't think about it when he first invented it, but you can read the full explanation by Jim Drake here:

http://joewindsurfer.blogspot.ca/2008/04/jim-drakes-windsurf-physics.html

Figure 9 shows it better than can be explained by words.

beaglebuddy · Joined: 10 Feb 2012 Posts: 1120

Wow that's some explanation from Drake, I'm not even gonna try and decipher all that. I'm a plumber not an engineer.