History of the Twin Fin and Mark Richards version
http://www.surfresearch.com.au/00000040.html
From another site.
Richards was interested in twin-fin surfboards and in shaping. At the Surfabout in 1976 he saw Reno Abellira on a highly manoeuvrable twin-fin fish and thought something like that would be better than a single-fin for small waves. Back in Hawaii again for the 1976/77 winter, aged 19, he took his father’s suggestion to pay for shaping lessons from noted pioneer Dick Brewer. It meant Richards was able to put his thoughts about design into actual foam. He credits Brewer for the style of shaping he came to use.
Brewer made Richards a twin-fin, and Richards took aspects of that and Abellira’s fish for his own designs. The result was boards faster and more manoeuvrable than the single-fins of the day.
I can add more as we go