i've already seen it somewhere.it works.actually creates a venturi effect,makin thrust ie:thruster.only the most skilled riders would benefit from this set up.
i have a quad setup in my js model and its my favorite fin setup so far im using 2) 4 and a quarter fins in the front and 2)3" in the rear.i have been surfing quads in the ocean a while now and behind the boat it works well because your tail doesent slide like a twin but you have the speed of a twin and the hold of a thruster when you want it but you can break it free easier
hey i cant seem to load any pics on here, but check out the naci glass movie edit, on www.mobgroup.tv im riding the quad fin. its the board with one orange rail and one blue rail, and im in the blue shorts with the white vest on.