Thrusters go great on windsurfers, a true thruster is an equalateral triangle, same distance from fin tips, across side fins tips,as side to back fin back fin same height as side fins but can have slighly less base length. A tri fin set up generally has a bigger back fin than the side fins and ares set to point about an inch of the nose as a true thruster the side fins point to the centre of the nose, the thruuster also has the side fins flat on the inside and foiled on the outside, rail side, most production boards are set up as quads or tri fins so the side fins are set to point about an inch off the centre nose line, ezzy make an off set fin to enable it to point to the nose centre, allthough most tri fin set ups you cant get the font fins forward far enough to get the same ditsance from the tip of the back fin as it is across the side fins because of the set of the fin boxes allthough you can cut the front of the side fins at tje bottom to slide them further forward. I like the 140 mm fin size for all three fins for the thruster thruster and i have gone back to fibreglass boards with glassed on fins to get the setup that i like and the extra weight only helps in big surf but i still use z booms so at 65 years old im too old to change just have to work on fitness to keep riding margs and gnaraloo. have fun and keep trying to get the fin set up that you like.
