Toe in and foil

General Discussion
1

If I were to give a slight toe in for keel fins, would it still be of any use/relevance to foil them on both sides? Does single foiling add to the effect of toe-in? Appreciate any and all info.

Cheers

2

My recollection is the double foiled fins felt like they started into turns smoother.  Those are “80/20” fins with convex curves on both sides.

3

try this-http://www.4wfs.com/

sorry for diging up a old post

i’m into fins…heavily at the moment…and loving the info here on swaylocks

p.s thu i did find this all on my own-http://www.ewp.rpi.edu/hartford/~ernesto/SPR/Ippolito-FinalReport.pdf

hope itdoesn’t bruise egos?

4

Fongss,

Thanks for finding that.

Now I’d like to see a deflection test between Glass on fins vs. Box fins

5

Hey Jay,

I don’t know the specific answer to your question, but I surf keeled fishes year round when it’s small.  Both single foiled, double foiled, and quads.  I set them up the traditional way. Double foil, no toe or cant.  Single foil, 1/8th toe in and a bit of cant.  I have not noticed any significant enhancement in performance of the single foil over double foil.  Perhaps a little loss in drive. A quad set up loosens them up a bit with a slight loss in drive.  Very subjective, but contradicting the usual advice that a single foil enhances performance. The most notable thing I have noticed, since I place them in the same location regardless of board, is how well the fins are foiled.  A poorly foiled fin gives me a poorly functioning board.  I like the Doc keel for lokbox, but my favorite is the short based Gepharts.  If I decide not to make my own.  Mike

6

I remember a discussion somewhere where the effect of double foil was to change the angle of attack (decrease from memory)

7

I hope Ernesto got his degree.  He should be happy that there wasn't a surfing engineer on his review board.  I think the results might have been different if he had done the evaluation on side fins as they carry the largest amount of flex/deformation, etc. vrs. the center fins in a thruster set-up.  He makes imperfect conclusions based on a single set of data for a configuration that uses three sub-sets instead of one.  However, if I was at FCS, or another of the injection molders, I would jump on this data for single fin (center fin) applications!!  Did I just say that?  my 2c.....