That's funny about the blue inserts. I use probox for the blue inserts to have less cant on certain fins I love. Then I can go to red or black with other fins.
Nice to have so many options with Probox inserts, but it is a double edged sword for a tinkerer..... Too many options. Reminds me I need to sew a fin pocket into my new shortjohn.
Zero degree inserts in the quad locations on my board actually have them leaning towards each other, with the double concave in that area. It felt horrible with zero degree quad inserts with the fcs1 carbon GYU fins in them. I switched to a thruster set up in the lineup and the board came alive underfoot. But I have yet to click with my board as a quad regardless of fin or cant, and am sticking to it as a thruster for now.
Sharkcountry, dont some of your fins have canted tabs? Are these futures rail fins modified with a shortened tab?
One day I Intend to use an installed insertless levelled rail probox as a mold , and submerge a fin into reinforced slow epoxy at whatever cant and toe in I narrow in upon, as my fin experiments continues.
I bought a set of FCS H2 fins a while ago, and when I stuck them in a normal board they just didn't look right. The FCS H2 fins have 10 degrees of cant built in and a bit of toe-in, so they are designed to have quite a bit of cant and more toe. I prefer to use them with zero degree boxes, but I stuck them in a board I have that has FCS Fusion boxes with 5 degrees of cant and they worked pretty good in there too.
I made a board just for the H2 fins with zero cant boxes, and only 1/8" of toe-in. I was blown away how well the board worked. I made a second board using the same fin setup and it was even better. The first board has a lot of rocker and the other has very little rocker, but they are both little rockets. That's what makes me love the fins, I think they make the boards better. I also only use them in the thruster setup. They seem to work best that way. For quads, I'm using a Stretch fin that I like, and I have a set from Robin Mair that I like.
I cut future fins to fit FCS tabs once and when I showed it to a friend out in the water I realized that one fin was gone. Never tried to do that again.
Those FCS H2 fins look a lot like a shark pectoral fin, which is a style which I have been experimenting with on my rail fins. Mine are ridiculously high aspect ratio and obviously look bizarre though.
However, they are highly responsive pivotal rockets. Little to no self centering, and much less stability. I like them most with 8 degree inserts, and the fins themselves have ~2 degrees of cant built in, as the fin panel was intended for being a center fin and I tapered the tip towards the center halo before foiling.
Interesting the FCS H2s 10 degree canted tabs, with 0 degree inserts are very similar in cant to my fins. When I went from 6 degree inserts to 8 degree I was impressed at the increased responsiveness and general positive feel.
The cedar fin shown above is unfortunately gone, lost when the grub screw was ripped out on impact with HPLB rail. The next set of similar template fins I made, originally intending them to be rear quads when I cut them out, are slightly less deep and have even less rake towards the tip. I can overpower them at slower speeds, and at higher speeds they can turn too easily in an arc my knees cannot withstand when pushing hard. I slowed this 'overrotation' tendency down with a lower aspect center fin. A cut down version of Mr Mik's Deaweeder.
I am liking the set up below the most so far in this board. The center fin tip is clear, rebuilt after it snapped off when it was a longboard fin.
The bigger sharky fins worked well with a smaller center fin. I rebuilt the broken one, which fits my backhand rail. It got slightly bigger and thicker and even stiffer when rebuilt, and I was having some issues on that rail post rebuild. I put the smaller one back in.
The next rail fins I make, I will lean this template back a smidge and design the tabs so they can sit slightly farther back on the board. I am not really willing to give up the low drag speed and response of the super high aspect ratio with thin narrow rake free tip, but can see the need for elongating the turning radius/ adding a degree of self centering stability, and a little more low speed grip.
Too cerebral for me. I don't think about much when I'm on a wave. Everything goes into autopilot and I just do what comes instinctually. I do think that fins need a bit of rake for the style of surfing I like. I can tell when a good set of fins are in versus a set that isn't working as well, but it's usually after I get a good set of fins. I also think that a good set of fins on one board doesn't always work as well in a totally different style of board. Change a rail shape and thickness and you can make a board better or worse. The fins won't help fix that if you get it wrong.
One thing I think people get wrong when we try to copy fish anatomy is that fish flex their bodies and constantly change the shape and stiffness of their fins. We don't have that ability with rigid parts. The textures on the surfaces can also be manipulated where we can only choose one texture. I this is why inflatable mats are so much fun, they constantly change as they move along the water.
All Good Points SharkCountry.
Almost every fin since Greenough's tuna fin is Biomimicry to one degree or another, yet no surfboard fin is able to propel the board and rider like the tailfluke of a fish does. The muscles in the tailfin of a fish pushing against the upwash caused by the rake no doubt help in the forward propulsion of the fish.
But surfboard fins are reactionary, bending out of the way when swinging the board through a turn, and only once bent can they rebound and provide any forward squirt, and only for a very limited duration. How much forward squirt they impart to board and rider is very dubious in my opinion, and much more so once one has tried and gotten used to the tendencies of fins with no raked tip, to impart any squirt on the rebound.
Higher aspect ratio has noticeably less drag, and very little resistance to swinging/pivoting the board when changing direction. When i go back to a lower aspect ratio fin, the first noticeable thing is it feels like someone cranked down the truck bolts on a skateboard, and when one is not turning the board self centers. Turns are slower but solid and predictable. It also feels like one overtightened the wheel bolt to add drag. Stiff trucks and built in brakes are likely a good thing on a steep hill. Added control, but what if the hill is not so steep and one has a headwind?
My long cruiser skateboards I always liked trucks so loose that the top washer would rattle. I cannot ride my buddy's board whose trucks are much tighter. I ride his board and I lean hard and board continues straight, and I have to put a foot down. My board I lean and the board easily swings under me. I am used to it, I like this. Personal preference
His board is set up for how he likes to ride it, and so is mine. The high aspect fins super tight turning radius is not something I am willing to give up at this point, nor their obvious lower drag.
The Probox's ability to allow me to experiment with fins to test and refine the feel is wonderful. I wish there were others nearby who had Proboxes in their board and were willing to try something outside the norm. I am not willing to shape some half moons into the base for my fins to fit gearbox
I've found a few to try MrMik's longboard fins. One guy surfed such a fin with way more amplitude on the wave, yet came back and said it did not have the squirt out of a turn. Yet the fin he was riding in this board was so stiff it was unlikely that the tip flexing out of the way could impart any accelleration at the end of a turn. I thought his surfing looked better with the HAR fin, sharper tighter turns in the pocket, yet he preferred a normal looking fin.
I lent one of mrMik's Harftub fins with 6.5 turbucles to Zak Flores who rode it in his 'midlength' and said he loved it, but not so much in his longboards.
One other guy, an older experienced surfer with lots of ability, whom I lent a fin to, and then did not see for 6 months, I heard from others through the grapevine, that he was raving how much he liked the fin, how fast and loose it was. Being one of the earliest of Mr Mik's 3d printed fins with no reinforcement from base up into fin and a weaker filament used, it had broken. When I saw him recently he was frothing like a little kid, and almost begged me for another. I sent him off with the fin the other guy said did not squirt out of turns, and one of the newest of Mr miks g-whale fins, thin and quite flexible. If he thought the other fin was fast and loose, the G-whale fin should blow his mind, except i think it is too flexible for his weight. But he rides a HPLB with sidebites whereas My Lb is heavy and traditional and I have found that very flexible fins unseat the rail of the board after a hard turn, and are squishy during it.
I think i will draw out some H2 looking templates to try, even though they are lower aspect ratio than what is currently floating my boat.
Too cerebral for me too.I can tell when they're working and letting me surf the way I like to surf. Or,not. I don't like flex if the waves have some juice. Small chest and head high days it's fun to have a flex fin. It's all personal. Like shoes. I would only add to sharkcountry's comment that shark fins flex, but are not movable like the bony fishes. Maybe look to that model for biomimicry. Particularly the leading edge angles. We move through the water slower than most all the fish. Mike
I find it interesting that we all have such a diverse view of what is best or worse.
I also think it's interesting that the fastest fish in the ocean have very long but narrow tail fins, but they are mostly for propulsion. The closest thing to those fish tails is Greenough's high speed fin. I've never tried one of these so I can't comment on them. I also have no idea if these would be something you could use as side fins. Then there's all the other fins on the fish, the dorsal fin, the fins on the underside, the pectoral fins. Seems like we have a look at how they all interact when these fish make quick sharp turns.
Best/worst, is mostly subjective opinion. I surf to have fun, not to make money or to be judged. I just want to increase the amount of fun I can have. I like going fast and turning hard and keeping that speed through turns, and get barrelled when the swell and location allow for that.
I am pursuing High Aspect Ratio fin experimentation on my HP multifinned board, as I used to want a big deep honking traditional looking dol-fin on my heavy traditional longboard. When I tried a HAR fin in it, despite my inherent bias against it, I was like 'wow this is so quick, such a low drag feeling, and I can hold more speed through the turns!', even if hissing cutbacks at high speed is not what traditional longboarding is about, and I have strong opinions on longboarding.
My mind was pretty much blown, and I wondered how much about surfboard/fin design that I and others, just accepted, and have not stopped wondering and questioning, since.
I wish I bookmarked, or could find the same youtube video of a Silky shark when it is all agitated, pre attack mode, pectoral fins pointing almost straight down, back arched, and seemingly pivoting so quickly on those pectoral fins as it S turned back and forth. It struck me then that that the shark pectoral fin in this orientation, is likely the most similar action to a turning multifinned HPSB, of most any fish fin in the ocean.
At that point I was well into the high aspect fins on my longboard and reading all I could on the design of the Spitfires Wingtips posted here, and a thread started by RDM, and decided I had to try it. I drew out a bunch of sharky pectoral fin shapes on cardboard cut them out and set them into my board's proboxes. Each one just looked wrong, still does, but I kept going.
So I made one fin for my frontside rail, Twin fin sized/depth despite my board being a thruster/quad, and being content with a TC Redline carbon FCS fin on my backhand rail. Soon after trying it, I made a 'sharky' HAR fin for my backhand rail too. Both are way stiffer than the fcs carbon fins and I only used the TC redline once since, and likely never will again. The TC redline template had been my favorite shortboard fin template for 2 decades prior.
Part of the reason I started capturing underwater video from a streamlined camera towed by my singlefin on my LB like in my avatar, was so I could see the expected tip vortex, and that it would be more prevalent the more rake and the lower the aspect ratio the fin had. The other reason is that I always wanted to, since the 90's, but the tech was not there or affordable.
I had expected almost an ever present tip vortex when I videoed my regular raked dol-fin, compared to MrMik's High Aspect Ratio turbucled fins, and while it was visible much more often for longer durations through and after turns, it was not as much as expected, but it was so obvious how much slower the board was underfoot, and how much slower it turned, when towing the camera with a LAR raked fin, compared to towing it with a HAR fin. I'll basically never ride my LAR dolfin in my longboard again either. MrMik keeps refining his fin thickness and flex, mailing me new ones, and they keep responding better in it. his fin has made my LB so much more fun to ride, and the waves I can take off on late and too deep, and still make, have also increased.
I think that fintip vortex is almost always present, but not always visible, and it is like a draggy soft rope, stuck to the tip of the fin, at various lengths, depending on how much pressure differential there is on each side of the fin. Its like a nearly invisible hand reaching out to grab the fin tip and slow the board down. The less upwash, the less the tip vortex, and thus less drag. But also less control/stability through turns, and one is likely entering/ initiating those turns with more speed, which is a bit unsettling the first few waves.
My current way of thinking is a narrow tip for not only easy repenetration of the shoreward fintip after a hard bottom turn, but for less lift produced at the fin tip, for less overall tip vortex, and higher aspect ratio, for less upwash and thus even less tip vortex and drag.
Since nobody makes such a bizarre looking fin, and being a cheapas$ who would likely not buy one even if they did, I made it myself, using a rail contour gauge to attempt to replicate an accurate foil, taken from MrMik's 3d printed ones, that use NACA or Eppler foils printed without any human induced foiling errors. Thicker fins are no doubt easier to foil accurately, and my SharkyHAR fins are all thicker than 3/8".... so far.
I am very much liking my SharkyHAR fins as rail fins, yet they lack stability/self centering, and can allow the board to turn in a much smaller arc than my 47 year old knees can currently handle, when I push hard at speed on chest high + waves with a high aspect ratio center fin. Which is a problem.
With a thruster setup, I thought why can't a bigger or further back or lower aspect ratio center/thruster fin serve as the resistance to overrotating when pushing hard with such low drag HAR rail fins that lack that attribute? Why should all three fins have to be lower aspect ratio and raked tips preventing that shorter turning radius? Why can't I have the low drag and speed of high aspect sharky style rail fins and tame down that undesirable tendency of too tight an arc that my knees cannot currently handle, solely by the shape/size/rake of the center fin? Experiments reveal that I can, although still in the early stages, and I do not get much if any chance to stall for the tube in my location. Some earlier HAR fins in my longboard would get all weird when stomping on tail to stall to stay in the pocket. Perhaps pocket stalling SharkyHars will not work well. Perhaps really grunty waves the lack of drag and control of HAR as rail fins is to be avoided. Perhaps the lack of fin drag can be mitigated with more tail rocker. Only Time and experimentation will tell.
Lower Aspect ratio center fin hanging farther back on the board, did indeed, to a significant degree, mitigate the 'too tight' an arc my board could take when put on rail and pushed hard. It did not feel like there was much increased drag over the turbucled thinner HAR center fins I had been using, which were farther forward in the probox, and which are in the process of being modified to fit further back.
I keep looking for the detraction, some sort of 'Ah HAAAA! ' moment, as to why these super high aspect ratio 'sharky' rail fins totally suck and are not used, and then understand why HP multifins look as they do and have since the era of MR twin fin and later anderson's thruster and then most every multifin since, but it has not hit me yet, even as extremely AbbeyNormal appearing as these fins are.
Mainly the lower aspect fins, when I return to them, strike me as being that way for added drag and slowing down the rate at which the board can turn, and self centering effect when longboarding. While predictable and easier to surf, because of that predictability, and the longer turning radius, it is a bit boring and dull in comparison, especially in relatively soft waves when trying to generate speed through pumping a shortboard or trimming high in the wave on a singlefin longboard
Seems that much about the design of HP shortboard rail and center fins is just variations on size and shape of the 'Dol-fin'. They obviously work, and work well, I just think that perhaps much of the accepted 'dol-fin' outline is simply a nod to tradition and perhaps a lack of will, past and present, to experiment further.
Drag = control, but what if there was the same amount of control, for less drag?
I am going to keep experimenting along these lines of SharkyHar railfins, despite the raised eyebrows they receive. I cut out and thickness tapered a new pair a few hours ago. I'll foil and glass them relatively soon.
If others have any desire to experiment with super High Aspect Ratio fins on a multifinned board, I'd recommend moving both the leading and the trailing edge of the fin back at least 1/4 inch over their normal placement, and perhaps keep a regular dolfin in the center the first few sessions at first. Make them a 1/4 inch deeper too.
Perhaps try just a HAR narrow tipped fin in the center finbox( further back) with regular rail fins. I've little doubt that most capable surfers would feel the board loosen up, and also have less drag. Whether they like this feel or not is of course subjective. It is a different feel, takes some time to learn, and some people hate anything different and should likely not experiment anyway.
Until I have made more SharkyHAR rail fins, I'll not be lending them out for those who might want to try them, and to those who also have Proboxes to install them into.
A very limited number no doubt.
Just to be clear, I didn't mean you and I talking about specific fins in the best/worse way, just in general in all I see here on Sways and at the beach.