Years ago - early 80’s - I rode some twins (all the ones I tried) and some tri’s (the wide thick tailed ones) which tracked like made and I vowed all that off for 15 years…
Well - I’ve made and enjoyed, on waves up to head high (But, the problems are a bottom configuration - not the fins, as I’ve ridden them as tris, and had the same “problems.”), some quads with a “McKee” type set up (My rear fins are even further in from the rail, but the boards are still looser than as tris.), but am leery to make the leap for a gun.
In communications with Robin Mair, I’ve come to appreciate the notion of the fin interaction of an edge finned board, but I’ve also read here, over the whiles, that some folk feel edge finned quads have tracky, twinesq, problems.
I’d love to read as many comparisons as possible, especially those of you who’ve experienced “trackyness,” but have found quads that do not track.
I don’t know what you have in mind when you say “gun,” because there seems to be a lot of variation in the use of the term. But I have a 7’0 that’s for the biggest days we get around here, and it’s a quad, and it does not track. I have the Takayama quad setup in there, and they’re designed for bigger, more powerful surf. I like them but think they’re a touch too flexy for me. The placement and bottom work very well, though, in DOH… shallow single concave with some vee out the back… the revised McKee placement specs for the fins.
I do agree that bottom has a lot to do with the quad setup, assuming we’re talking about the back fins. I think we can agree that the front fins are pretty standard. I think concaves can better handle back fins set more toward the rail. Pavel’s Speed Dialer is a good example. Concaves are designed to hold more water under the board, and fins on the edge complement that. Convex bottoms, like vee bottoms, allow more water to release off the rail, so putting fins out on the rail makes less sense to me. I had one of those quads back in the day, too. Tracked like hell. Vee bottom (like most boards at the time), with fins out on the rail. Gave up riding quads for the rest of the millenium!
I currently have another board, a 6’4, with a shallow single to double… old McKee placement specs. Works great, and not tracky at all until it gets overhead. But that’s not what the board was designed for. Under head high, the thing rips, AND it’s faster than most other boards in the water.
Hey NJ - Thanks for responding. Is the “Takayama” set up more of an “edge finned” set up?
By “Gun” I’m talking about 9’+. But, I’d be interested in trying it shorter too. I’m interested in a set up that would work from my “short” board 6’8" up to my biggest gun 10’7". I like my test rider’s theory about a general shape and set up that works well, then as you go up in size in your quiver the ride will be similar and consistent. One reason I’ve stuck with “kick tailed” tris.
I’m stoked to read what you wrote about bottom contours… concave/Vee… Good stuff for me to think about. My “kick tails” are an angle @ 25% of board length from tail, I have it written down, but don’t remember off the top of my head - I think it’s about 3 degrees - Anyway, the rocker at the stringer is flat behind the kick through the rear fin, then a little kick. I put heavy V behind the kick, up to 1/4", but I also put concaves on each side about 3/16" deep. Well, that’s working well for me on my tri’s… And I’ve talked about the other “problems” (The incidental extreme rocker) with my “shorter” quads, so I’m not keeping that in the equation.
I hope to hear what others think about “edge finned” boards, and bottom contours…
Makes me wish some one around here had a good one I could try… I saw one guy from up north with a “Stretch” quad…
I have a shortboard (6’3x19x2 1/4") I made a short time ago using a quad layout that Robin sent to me. I have the probox QuadESC fins in it. I’ve felt zero problems with trackiness except for when I tried the fins with 6 and 0 degree inserts and spread the cluster far apart. This board I now use 6 and 4 degrees on the front and back respectively, and for me it’s almost perfect. I think the 8 degree would work better if not for the considerable tail rocker plus the spiral vee that makes for a pretty loose board when you step on the tail. With the 6 degree it is possible to slide the tail in snaps, but it holds firmly through roundhouse cutbacks if that’s what you want to do; the 8 was too squirrelly on hard turns and high speeds.
I’m totally happy with how it feels.
That said, I AM looking forward to seeing and hearing more about Herb Spitzer’s boattail ‘pulled to the center’ quad setup!
By “spreading the cluster further apart” he means moving the fins further apart therefore increasing the gap between the fins.
The beauty of using a fin system that allows you to move the fins forward and back is that it allows you to play around with the gap very easily. I set mine up so that the fins are centered in the box when positioned with my desired gap, then you have the option of going either way with the gap. It is amazing what a difference a small amount of adjustment will make, never fails to blow my mind. Cant can also have a big impact. On my boards I set them up with 8 degree cant in the front and 4 degree in the back, but the main reason for the higher cant in the front is because of the deep concaves in that area which makes the box go a little negative, so they really end up at about 6 degrees.
I tend to use a larger gap on longer guns in order to make them a little more “tracky”, but I more commonly switch the larger fin to the back if I want to draw out the turns (my assumed definition of what you mean when you say “tracky”). Then if that is not enough I start spreading the fins further apart. But I have to be honest on my own boards I never change them once I find the sweet spot and most of the time I leave the larger fin in the front.
As I mentioned in some of our correspondence all of this can be affected by a lot of other variables, such as the bottom shape, rail shape, and more importantly the fin templates, and of course lets not forget cant. I have been finding myself designing more and more quad specific templates based on what is desired from the board and the waves it will be ridden in. So there are definitely a lot of variables to consider and the best way to get them all figured out is to experiment, which is the fun part of surfing as you get to try all of these variables, especially easy if you make your own boards. If you don’t then get a board with a removable adjustable fin system that encourages experimentation!
Robin nailed it on the head re. the cluster, of course. I just tried it with the front fins all the way to the front of the proboxes and the back fins all the way to the back one day and it was definitely too stiff and tracky that way. But like he said it is absolutely amazing how much variety you can get out of the board with a system that offers that much flexibility, especially with quads. I have a couple different placements that I have now narrowed it down to, the one I mentioned above is the go-to, and then I have another setting that I like more for a particular break that I sometimes surf. For every wave and every rider, a different placement, really. Too much fun!
The spiral vee as it was explained to me is essentially vee with a double concave that runs into and through the vee… so that the angles of the vee on either side of the stringer, instead of being flat, have a concave curve to them when looking at a cross-section slice of the board. My understanding is that it helps direct the water back and diagonally out of the vee, even more than standard flat vee does.
…does that make sense? It was explained much better to me by surfteach, if you want I could dig up his explanation I’m sure it’s somewhere in my PMs.
Thanks again Robin - I was hoping he’d say how far was “too far” for him.
By “tracky” - what I mean is: I’ve ridden boards that tended not to “go on rail” and turn at all, almost, or maybe only turn a little bit while the board seemed to stay flat on the water. They were OK if I took off at an angle (already on edge), and I could work up and down the face, but could not cut back. As I thought about and wrote that, I realize a lot of that may have had to do with the thickness and width, but then again I’ve read others write of “trackyness,” but I don’t know what they mean for sure.
I’ve found, similar to your definition of tracky, if I want to draw out turns, for stability in bigger waves, I can move the center fin back on my tri’s. My concern, having read what others have said about “tracky” quads is not long turns, but not being able to get on edge and turn much at all. I’m gonna try another angle - new thread, Ha!
I don’t know if this is really the case or not but I have felt myself that some of that conception of quads as not being able to get on edge probably has more to do with poorly designed quads than the fact that they are quads… maybe the misconception that quads should have wide wide tails and not compensation for that width with some vee…? Or simply from ineffectively placed quad setups…? I have heard more complaints of trackiness from the McKee setup than from the speed dialer or Robin’s setup. I don’t know I don’t have that much experience with production quads though, so who knows. It’s a different beast than a thruster though for sure. I had a shortboard quad made for me by a local shaper and it had that kind of a feel to it. I salvaged it by squeezing the cluster as close together as I could with the FCS fusion plugs it came with; you only get a small adjustment range with them though. Still, I can honestly say that my homemade shortboard with Robin’s placement surfs twice as well, without any of that trackiness.
This is one of the reasons I prefer the fins closer to the rail as that really helps the board get up on the rail, and once up they really hold. I have done quads with extremely wide tails that have absolutely no problem getting on edge. In fact my experience with quads (when placed closer to the rail) is that they excel at doing this and is one of the main reasons I like them so much. So for me the closeness to the rail was the key to enhancing this capability.
If a quad is having problems getting on edge it is more likely to be the placement of the fins relative to the rail (possibly also a combination of toe-in and cant), but more importantly the fin template (to much base length) and the size of the fins. If there is to much fin on the rail there could be problems, so getting the right amount of fin area is really important as far as I’m concerned. I’m always looking to get by with the least amount of fin area possible without sacrificing drive and hold.
What you’ve written about fins - esp. base length - makes a lot of sense too. (I’ve seen your “thumb” fin… Ha! Right on!) It speaks to me when you mention the fins on the edge… Many of those old boards had big ol’ fins on 'em.
When you mention the amount of fin area - what do you use as a basis?
I’ve got the impression, from things I’ve read, the having about the same amount of total fin area as a tri is a good rule of thumb (Oh, maybe that’s why you have those low fin area fins called “thumbs”… Ha1).
It’s interesting to read this after just reading the Rusty quad thing…
I don’t have a magic formula for the fin area, instead what I do when designing a fin is I take a standard template, with some know performance characteristics or that I have direct experience with, and then design a fin that enhances all the properties I’m interested in, while focusing on reducing the amount of area in the new design when compared to the standard one.
So lets say it is a 4.75" height fin, the new design will have the same height, but then where the base of the standard fin might have been say 5", I would reduce it down to say 4" or less in order to enhance the turning capabilities. Now this means that you have immediately lost a lot of area and therefore drive, so I will push some of the area out towards the tip to add back the drive, but I won’t use all of the area so that overall I have improved the turning ability, reduced the drag without sacrificing the drive because I have placed the drive area closer to the tip where it is more effective. I might also push some of that area out into the tip to increase the rake of the fin so that the fin can be placed further forward in the board to further enhance the turning ability, but without sacrificing hold because there is so much more area in the tip but further back because of the rake. For a lot of my designs I then like to factor flex into the whole equation so that I can use the extra kick from the flex to counteract some of the potential loss in drive due to reduced area.
Then for quads I always look at the two fins as serving somewhat different roles, the larger fin is the engine and the smaller one is a steering and stabilizing fin, while still providing some drive. Therefore, often the two templates are totally different to enhance their respective characteristics and the role they will be playing in the setup. For some quad designs I like to take what would have been a keel fin and split it into two fins so that they form a matched set, my experience has been that this dramatically improves their performance and versatility if it is done right, in this scenario I still treat one as the engine and the other as the steering and stabilizing. The only downside to this approach is that these designs typically do not lend themselves to switching the fins around as they would no longer match up, although that does not mean they wouldn’t work, just might not be optimal.
So in terms of finding the right area, I mainly do it by experimentation. Most of my fins designs cover a range of sizes in 1/4" increments, so I typically will start out with a larger fin and then slowly go smaller until I find out that there is not enough area and then back off. But with some of the templates that I have had for years I have now reached the point where I can instinctively tell by looking at a board what the optimal size will be for a given combination.
Not very scientific I realize but sometimes experience with something trumps science!
Robin that’s all really great information… I’m especially interested as I recently made a small fin panel to make a couple of fins that I would like for a weird egg I have, some sidebites etc. I read elsewhere on swaylocks somebody said that a minimum of 45 layers of 6 oz made for a thick enough panel; mine I used 40 going by this information but it seems extremely thick! (Haven’t actually measured it yet) How do you feel about thickness in your fins? Your QuadESC’s seem to me to have a very curvy, sudden foil in the lower half of the fin but other than the small area that makes up their thickest point they seem quite thin overall… Do you find more thickness suits some fin types more or changes the optimal area of a fin template?
Typically, our fin panels are sized to fit the fin boxes, so for ProBox that would be 1/4". There is no doubt that thicker fins can have different performance characteristics but for the production of fins it is a lot easier to try and have the panel match as close as possible the base thickness requirements. We have a special machine that takes the base thickness down to the exact correct thickness tolerances so we could do thicker panels but the cost would go up as there is more material much of which gets foiled away. So for us it is a balance between efficiency, weight and cost.
I have done a lot of experimenting with thicker fins and have always loved how they work if correctly foiled!
To me the thickness becomes more critical the greater the chord length of the fin at its widest point, so for example, if you have a fin with a 7" base and it is only 1/4" thick it will be hard to get a decent foil out of it.
With thickness you also have to take into consideration the impact it will have on flex if that is something you care about. With most of my designs I care a lot about flex so I tend to steer away from to much thickness.
I stumbled across this a while back on a board I built.I made a 6’6 webber fatburner using eps and bamboo skins,flat bottom.I used the Mckee quad placement for the front fins only,they were 1"1/4 off the rail 1/4" of toe and 5 degrees cant.The front side of the trailing fins were 5/8" back from the trailing edge of the front fins with an identical setup as the front fins off the rail,toe and cant.The original board was a tri fin and I wanted to loosen it up and make it faster and I feel I have succeeded and then some.You can actually drive up the face of the wave and the board releases from the top very easily.The board is easy to ride and do airs with,its very snappy alsoThe fins I coppied were the fcs stretch quads.It was luck that it all worked together IMO,seeing as it was my second build.
Awesome, thanks for the extra info Robin; makes sense r.e. making them the right thickness; that is what I should have been aiming for. Now I have to figure out a way to get a clean straight reduction in thickness so my fins will fit probox! D-oh…
I’ve never entirely understood the term ‘chord length’ but I think that makes sense. I guess that explains to some degree why many older twin fin fish have quite thick wooden keels; the length of the base makes for a poor foil otherwise! Revelation…
I thought I had replied to one of your emails that any time you are here you are more than welcome to take any of the boards I have for a ride out at the Bay (or anywhere else), no problems, if you want to do some real Hawaiian testing.
it seems so obvious to me that all the experimentation with fin placement for quads is possibly best achieved with 4 way fin system: www.4wfs.com after all ,not only can the fin be adjusted to change toe-in/out, fore and aft, splay, and even rail offset adjustments are now available with 4 ways.
what i am referring to, is instant adjustment with instant results to suit different surf conditions and surfers styles.
one quad placement may suit one surfer but not everyone, adjustability is key to unlock every board's potential, especially when it comes to quads as it's a very new experience for most surfers!
keep it going guys,
i find it facinating!
i'm converted, just keen to see how many others feel the same...