Only just beginning to consider fin shape/intention, this site gives a few basic concepts of what particular fins are designed to do. Must be lots of info out there but perhaps not all using terminology the rest of us mortals can understand
allaboutsurfboards.com/surfboard-fin-design/
Yep made to "assure great noserides",like an improved version of the original tunnel fin back in the sixties,it did seem to help but at the expense of drag..
George Greenough....his board flexed....his fins flexed......a great pioneer of fin development (yes i used to be a kneeboarder 
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Perhaps this is the perfect fin....
"This fin set is suited for the surfer between 65kg and 80kg. The fins are made from a honeycomb/ fiberglass construction which gives the feeling of a solid fiberglass fin but significantly lighter. The base of the fin has carbon which makes it super responsive, fast and light perfect for the surfer wanting to go to the next level of performance."
Don't want to hijack the thread but,I ride my longboards (10 ft11ft &12ft) as single fins(9 inch and10 inch) however the 11 and the 12 have provision for side fins the semi thruster type set up.My sup also 12ft (Simon Anderson Nimitz) I also ride as a single fin without the side fins.I must admit to never trying the small side fins.The subject is about fins,my question is what difference should I expect in paddling and surfing small waves with the small side fins in.Does the performance difference outweigh the drag ,and in small to tiny surf would it in fact make much difference.Maybe I'm really missing out ,maybe Simon Anderson meant it to used with 3 fins(he did invent the thruster didn't he). Bear in mind I've surfed a long time single fin only,and never really had much to do with thrusters etc .Your input welcomed .....Cheers
