I like quads, they work well for me with the waves I ride and how I like to surf. I’m over 6o now so I am more about driving, creating speed than vertical surfing
The one thing I don’t like is figuring out the best fin sets for each board- once I get it figured out I usually leave them alone. I’ve got a bigger quad fish I’m working through right now, I’ve got many sets of fins so I’m playing with different combos
I think I remember reading someone described that with quads " the front fins are what initiates/creates the turn , the back set provides the control or drive"
interested in hearing what people like and don’t like , any pearls of wisdom, etc
I have single fins and I have quads and have not yet ridden a thruster or 2+1 that I like. I always go back to the others because they feel faster. But Im not an advanced surfer yet and I suspect the day will come when I see the value of thrusters. My 8’2 quad swallow tail originally felt difficult to ride in the beginning, thinking the elaborate bottom contour and hard rails were slowing it down. I almost sold it. One day i shopped for the smallest quad set I could find and put those in instead. It made a world of difference and now I ride it alot.
I’m designing a 6’0" with quads in mind and here are the things I’ve been reading up on, here and elswhere. The closer the front and rear fins are in size, the more neutral they will feel. Larger front fins than back make your turns pivot more. Bigger back fins than front project more. Using stiff front fins give it drive. Tail width can affect quads more than a thruster setup. A wide tail quad can over-steer because you have to push it harder to sink the wider tail and once it does half of your fin area is now up out of the water, with the other two engages on the opposite side. A thruster in comparison always has that rear center fin to stabalize. If a quad setup feels too wild, move the rear fins in towards the center a bit and it becomes more stable. Or you can set it up with a tail with less width, because in turn the quad fins will be that much closer to the middle, so more control. Quads can wash out in white water because the turbulence is hitting four separate points differently, less so with thruster or single.
One thing I don’t understand about quads vs thursters is their relationship of fin area to speed. If I take four fins that have a greater total area than three fins, then why does the quad paddle or ride faster? Is it the drag caused by their cant/toe in, because the thruster rear fin has neither? Ive also heard folks say that water if funneled into the center of the board out the back, so quads dont disturb that but the rear thruster fin does. Is that true? I dont know.
I also just watched an interview with Stretch and his points were: Boards pivot around fins. So with a thruster, the faster you go, the more stable it becomes. With quads, on the other hand, all four fins rotate around the central point between the fins. So speed doesn’t give quads more stability. The looseness of quads is the same fast as they are slow.
Quads also look very aggressive when I’m walking the board out of the water past the ladies, and this compensates for the growing bald spot on my 49 year old head.
My understanding is that the wider the base of the fin, the more drive the fin will have. And drive relates to acceleration and maintaining speed through turns.
Toe in causes more drag, but the theory is that it makes the fins more manueverable, because the water flow generally moves outward from the center of the board. That’s why lots of traditional Fish designs dont have any toe-in angle on the fins. That makes them really fast down the line… but can be more difficult to manuever them through turns.
I think the C-Drive fin describes lots of the differences between drive, drag and release… because it encompasses lots of those things in the fin design.
The length of the base affects forward drive. More length equals more drive but typically this comes at the cost of things like maneuverability and looseness. To negate these effects the C-Drive team made other modifications.The second noticeable difference in the C-Drive fin is the cut away section. This feature allows the fin system to maintain its increased base length while minimizing surface area.
I think part of it comes down to the amount of fin area. Thruster center fins have a wider base than Quad rears… but that one center fin (thruster) offsets the fin area of the two rears (quad).
It’s kinda like how Rob Machado describes his quad rears having about the fin area that he took away from the front fins (if they were a twin keel).
This is really interesting… thanks for posting it. I have a really wide tailed groveler with a tri-quad setup and I’ve always had lots of problems with it being too loose when using the quads vs other quad boards that I have. That makes a lot more sense to me know. I guess I’ll probably need to use oversized quads, if I’m gonna use that setup on the board. And maybe avoid choppy conditions with it
Thats correct from what I’ve read. Water is channeled through the center of a quad faster… without the drag created by the center fin of a thruster. Channel Bottom designs try to bring together the best of both.
Surf without fins, you have nothing to push against except part of board you can put in water. Now add fins, you can push on water via fins and water push you, projection, depend orientation of fin. More fin area more projection, in a turn most quad setup have more surface ie more projection ie more speed. Down the line 2 fins locked in water ie more grip can ride higher in the curl so potentially more speed. But more fins engaged ie more track…
own quads = a box of quad fins as well…and personally prefer the Rusty quad formula for rear’s, 60/40’s the distance from stringer to rail…plenty of drive, more of an anchored feeling than when the rears are closer to rail…Simon Anderson quad fin’s a good all around design.
A huge fan of racy quad mid lengths and HPLB’s…definitely have an extra gear when hauling okole down the line…
i like those boards. didnt know rusty had a different method, thanks for the clue. will be reading up on this related thread, It’s Rusty talking in detail on Surfline about his theory and practive of quads vs thrusters, worth reading
