The fin you use, depends entirely on the design of the board.
If you have a large centerboard/daggerboard (that you cannot change easily and cannot change the position of at all) then playing with some different (not always smaller) rear fins can give better upwind performance.
If you have a board with a removable center fin, then you need to experiment with both the center fin and rear fin to find a combination that will work with the size rigs you are using.
I've had very little luck with rigs < 2.5 m2 because the boards are built with the mast track too far forward to allow any sort of good balance with smaller rigs.
The smaller rigs have the CE of the sail only a few inches behind the mast.
If you cannot slide the mast foot far enough back to get the CE of the rig over (behind slightly is better) the CLR of the centerboard or center fin, there's no way you (or your kid/student) can sail the board upwind.
I've had my share of "embarrassments" when sailing with really small children on boards where the mast foot won't come back far enough.
They sail the board and we go downwind.
I let them sit on the front and I sail the board and we go downwind.
Rather than sail off into the sunset, I usually end up sitting on the front with the child holding the rig up (pretending they are sailing upwind) while I paddle with my hands back to the beach.
I did some testing on the '06 Starsurfer M and I proved (to myself anyway) that for really small rigs (< 2.5 m2) adding an auxiliary "extension" to the mast track slot really helps to overcome this problem.
This is why I like the older Starts with the removable center fin better as I can use different fins to overcome this problem.
As far as "turning", that's never a problem with my students.
If your students were to use the same techniques they would have no trouble turning the board.
When my kids tack, the foot of the sail goes right down on the board with the foot on or slightly past (upwind of) the centerline.
This steers the board right up through the eye of the wind with no problems, and the sail supports itself with the foot resting on the deck of the board at the back.
We call this (in "A Taste of Windsurfing") a "faster tack" as the rig is sheeted in gradually and raked back at the same time so it "drives" the board up into the wind and usually well past "the eye of the wind".
Try it, it works.
Also, we teach our students to "step over" the mast behind the mast foot.
If your student doesn't get the rig all the way back and down on the deck, or if they step forward around the mast base and pull the rig back up as they cross in front of the mast foot, then the board instantly stops turning and heads directly upwind because that's what the "steerage" from the rig is telling it to do.
I talked to one of my sponsors today and his daughters were having some problems staying upwind in the Gorge. He solved this problem pretty easily.
He cut off an older 70 cm Deboichet Formula fin to 44 cm. and he puts this fin in the center fin box on an '01/'02 Start. Now his girls stay upwind with no problem.
I see alot of people who use smaller fins, but I've had much better success with using std. 39-41 cm cleaver (shallow Water) fins. Smaller fins do not seem to be able to keep the board upwind.
If the rig is balanced, steering while underway is never a problem, but staying upwind can be a problem.
Hope this helps,
Last edited by Roger; 5th March 2008 at 10:34 AM.