Quote: [tropic surfer Sorta old school question...doesn't all those extra fins create more drag and make the board slower? Surfer mag recently had an article about Derek Hynde and his finless boards and the speed of the designs was from reduced friction.]
I have wondered the same thing about quads myself.
But once up to speed a good quad feels so fast. I can only figure the quads (all four fins canted out) produce more lift in the rear of the board and this gets the board on a really nice efficient plane, and lift might actually reduce drag.
The trailer fin on a thruster is vertical so it produces less or maybe even no lift at all.