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.
Maybe lbcrew knows what's up?
Mitchell and LB Crew makes some good points.
My understanding is there MAY be a slight difference in location for the fronts for a quad vs a thruster based on how your shaper does things (everyone doesn't use the formula) So make sure the shaper has experience on 3/4/5 set ups.
I have found that boards I get shaped with 5 boxes - I usually like it better one way and don't switch back and forth too much, but having the option is nice anyway
The guy I get my boards from has some nice pic's on his Blog of different board options, give him a call he is a wealth of info
LBCrew is getting a little technical with the cant variations. Hell, I should just pay him to shape me a board. Would never use the 5 fin setup in it's truest form as I can't imagine the resistance in non-reefbreak type conditions. I'm just looking for a quad on clean days when it's barreling and a thruster on sloppy days when conditions aren't as predictable.
Originally Posted by tropic surfer
5 fin setups are great for versatility but you are always sacrificing something. The front fin placement on a quad vs thruster is slightly different. When setting up a board for 5 fins the shaper will usually find that middle ground for the front fins that allows both, but is never optimized. Don't be discouraged to try it, because the benefits of versatility can outweigh the very slight performance difference.
Quad placement is very board and surfer specific. It is much harder to get the optimal placement for a quad than a thruster. Thrusters are in some ways, a dumbed down quad. You'll notice some shapers putting their rear fins closer together and some closer to the rail. The closer the rears fins are, the more the board will ride like a thruster.
The reason a quad will be faster than a thruster, even though it has more fins, is that the front disrupts the flow of the water (friction) and the rear fins sits in the path of that disrupted water. So, it's almost like having only two fins as far as friction goes, but you have four fins in the water for control and hold. When you place the rear fins of quad closer together you begin to lose that benefit because the rears are no longer in the path of water flow from the fronts. To compensate for this you can use smaller rear fins.
There is much more science involved in quads, but once you get them dialed, you might not want to go back to your thruster.
Wayne is an amazingly talented shaper.
Originally Posted by JTS
Originally Posted by mitchell
I ride the quad set up with the rears a little back and to the center like you're talking about but the tails are pulled in more than usual so the boards are pretty loose. If your on a standard tail with the same set up all you have to do is change the rears till you get the feel you want. Fcs Q1's are major loose, GX's with a 80/20 foil a little more stable and gx's with a 50/50 foil are the most stable for this type of set up.
Originally Posted by tropic surfer
I think this varies from person to person really. I'm a big guy and have always felt like thrusters were not as responsive and slower for me than quads. I always rode mine as twins except for big days when I would put a small GS in the rear. Rode a pop out quad once and it really didnt work for me so now I get my boards custom and I havent had a bad stick since. I dont think you can blame drag just on the # of fins on a board. Your shape and concaves can kill speed just as well.
Regarding finned vs. finless boards and speed... I always say "speed" is a relative term, because there's down-the-line speed and there's speed through turns. Finless boards (and by the way, Derek Hynd's finless boards have wild channel configurations and other bottom designs to direct water flow) are faster down the line. No fins, no fin drag. But finned boards are faster through tight radius turns, which are what most guys are after who ride thrusters and quads. If you watch guys who are good at finless surfing, there's not a lot of top-to-bottom-to-top, vertical surfing. Finless boards do big, banking turns, using the bottom of the board, the rail, and the rocker/flex of the board to leverage off the water. But to do a modern, tight radius turn, you'd have to scrub off a lot of speed. That's why you see these guys doing a lot of spins, and using only about 2/3 of the wave face on a finless board.
Everybody feels something different when comparing thrusters and quads, but for me... finned surfing, particularly on multi-finned boards, is off the back foot... singles less so. Leverage is provided by the fins, and the fin engages the turn. The rail follows. The disadvantage of a finned board is a lower top end in down-the-line speed (when compared to a finless board), but the advantages are being able to do hard, tight turns in critical parts of the wave, and hold on a steep wave face. Quads hold more speed through turns because there's less drag through a turn from a single foiled and toed rear quad fin than a double foiled, straight ahead trailer on a thruster. Quads hold more speed through the turn, but the turn is more open... a longer turning radius. A thruster will do a tighter radius turn, but will not hold as much speed. A quad will also let you take a higher, faster line on a steeper part of the wave face. The big disadvantage of a quad is that you lose that loose, tail slidey feeling a thruster gives when you want to push the tail around with your back foot. So a thruster will release better blowing the tail out, will get the board around faster through a snap, and will recover better from rotational maneuvers.
Not bored yet... read on... you will be soon...
What somebody said about more lift from a quad giving a flatter, more efficient planing surface is also true, which translates into more speed. But you also have to consider fin cant. You can regulate your lift with cant, and tune your board to wave size and speed... more cant will give you more lift in slower, weaker surf. Less cant in bigger, faster surf for less lift and more control. Personally, I go with a thruster in big surf, and a quad in small surf. Just makes sense to me.
Finally... regarding the position of the rear fins on a quad, I put a lot of consideration into not only what kind of ride the surfer is after, but bottom contours. All fins out on the rail work better with some contours, and fins closer to the stringer work better with others. But that's a whole other discussion...
Originally Posted by LBCrew
That was funny, but I love this stuff.:cool: