Football fin

General Discussion
1

I came across a  football fin and would like to use it in my 10 foot longboard. 

Can anobody explain the rationally under this design?

Thanks in advance

2

If you are reffering to an elliptical fin, read this wiki page: http://en.wikipedia.org/wiki/Elliptical_wing

With classic analytical aerodynamics, one can proove that for subsonic flows, an elliptical wing shape is the most efficient.

3

I think this is what he was referring to,