Mitchell... Now THAT'S what I like to see! Good old fashion DIY, giving the proverbial finger to the surfing establishment. Good job! Now grind down those boxes, wax it up, and drive to the OBX if you have to! WRT Canards... they're just a typical keel fin split roughly down the center. The rear is placed exactly where you'd place a keel fin, and the front is slid railward of where it would sit if it where still connected to the rear fin. It gets its name from the canard wings on some aircraft, which is a small wing set ahead of the main flight wing with a slightly different foil angle. The canard helps improve efficiency and eliminate stall at low speeds and high angles of attack... the same principles you hear fin guys talk about... efficiency, stall, angles of attack... but in different contexts. So while they're really not doing the exact same thing, the theories are similar, so that's where it gets its name. Bruce McKee... he's setting his front quad fins considerably further back than the front fins on most thruster PSBs. This give more drive and speed, but sacrifices snap and responsiveness, particularly off the top. To compensate, he's moved his rear fins much closer to the stringer, and further forward, tightening the cluster and loosening up the ride. The result is a quad with a more "thruster-y" feel to it with some speed advantages over the thruster. Quads with all four fins out on the rail (which is what most guys seem to want) tend to be a bit too tracky. So most board builders have moved the entire fin config forward, putting most of the fin area under the back foot, and increasing pivot and responsiveness. So that's likely what you're seeing when you compare your typical thrusters to your quads. Also... keep in mind that for the past 8-10 years or so, at least, front fins have moved forward in general. With all the emphasis on tail slides and airs, moving the front fins forward helps facilitate this approach. So it all boils down to how you surf and what waves you want your board to work best in. There are no hard and fast rules. Doing exactly what you did... measuring some of the boards you like and figuring it out from there... is the best way dial in your fin placements for a garage guy building a board for himself.
I have a Tommy Moore Round nose fish that has a 5 fin convertible set up, but dont like it as much running it as a quad. It seems to me that the Quad (rears) placements on the convertibles is located a bit different than the ones in my straight up quad. Anyway I prefer the thruster set up in my fRNF. I also run larger fronts, and a small mini trailing fin, but i dont use the large MR twin fin style, I use the FCS k.2 fin up front and the GS for a trailer. The mini trailing fin has enough bite to keep the from skipping out on hard turns off the bottom in average surf (wasit to shoulder) but allows the tail to release so easy off the top. When I do run this board as a Quad I use the K.2 Quad set up. Granted i havent given it much of chance riding as a quad becuase good waves i typically ride with a proven fin set up. It really depends on the baord your ordering. THe convertible set up might work great in a more high perfromance style board.
Done! All this work and waves slowed this project down... I tried something on this board i've always wanted to: Poly blank, epoxy glassing, poly hotcoat. 6'2" x 20.5" x 2.5" plenty of volume...should be a good winter board. I hate the wierd flat spot/bump about a foot from the tail, but it might not matter except to the eye.
Slater rode with 5 fins in the board during the quicksilver NY contest. basically a quad with a little trailer fin in the middle..hard to believe it does much since it was only mabye 2 inches tall.
Nice work, mitchell. I wouldn't worry about that bump in the tail rail... the bump I see is at the trailing edge of the rear rail fins, and the straight part ahead of that. I think that makes sense from a design perspective. The straight spot will make it fast. Then the hip behind the fin pulls in the tail for release to loosen it up. Sometimes the eye can tell you one thing, but the ride might tell you another. What kind of bottom contours did you say you put in?
Thanks! Mild single concave starting under the chest and through the middle. moderate double concave starting in front of the fin cluster and running out the tail. rolled vee staring near the forward fins and getting more pronounced out the tail.
