OK Bud Man,
About 1983, WaterSki magazine ran a photo of one of my fins with dual tubes rather than dual wings. I found that the upper tubes/wings controlled deceleration and the lower wings controlled the turn so dual wings/tubes go way back to the beginning. As for the philosophy behind the Ventral’s, I have no idea. To me, they just look like more drag that will allow you to pull too long! As for Joe Darwin testing something at 32 off, I don't feel it's a real test. Whenever I would test anything on my ski, I always went "upstairs" to my hardest passes to see if the change was better or worse. I really don't care how a ski feels on a warm up pass. It needs to perform at the top! I'll gladly test one if someone will send it to me along with the mounting and tuning instructions. To do this, I will have to destroy a $70.00 fin!