Ken Winner the "inventor" of wide boards - had a rule of thumb for the minimum distance from the trailing edge of the fin and the stern of the board to minimize the risk for "ventilating" the fin, namely 3" (approx. 7.5 cm).

Make this lower case
ken winner the "inventor" of wide boards - had a rule of thumb for the minimum distance from the trailing edge of the fin and the stern of the board to minimize the risk for "ventilating" the fin, namely 3" (approx. 7.5 cm).