On the right, Velo's massive 10" deep x 8.5" base x 5/8" thick fin. (Approximately 13.5 to 1 thickness-to-width aspect ratio.) 1966.
On the left, the edge board's narrow 9" deep x 5" base x 7/8" thick fin. (Approximately 5.5 to 1 thickness-to-width aspect ratio.) 1972.
As profoundly different as these designs are, they netted the same handling result in the water because they were used on completely different boards. The narrow, white fin isn't "more advanced," even though it came along 6 years later. It evolved to address the needs of Greenough's edge boards.
The point is...a good fin design doesn't become obsolete! What matters is the handling balance it generates on the specific board it's used on.
Posted by Paul Gross