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.
No worries, i did not take it that way.
I am not trying to be argumentative nor insulting . I like your threads, input and experimentations regarding fins and board design and ability to think outside the box and value your experience and willingness to share.
So since i had your attention, tried to hold it. Your bringing up the FCS h2s alone was worth it. ;)
If I were on Oahu, I'd be asking you to put my SharkyHARs in one of your proboxxed boards to try. Still might, when I make more and refine them some more...
Funny how the H2 hasn't recieved the attention I thought it would get, but now everyone is making the hollow foil on the side fins and they all have their favorite shape. One thing I need to research is the H2 in a position (cant and tow) that it wasn't designed to be used at. I do know that they have a unique hum in the zero cant boxes, but I didn't hear it in another board I have. I'm not going to let that hum stop me from using them the way I've been using them, but I'll have to see if they are even better with more cant. Lots of things to check out this summer.
I did not realize the H2's had a concave inside foil on the rail fins. How much more toe in do you think the offset fcs tabs add? How deep is the concave?
I don't find it very surprising such fins never got much attention, as they look so far outside the expected dol-fin shape that both surfer and non surfer eyes have been trained to expect, and the general surfing public are a bunch of sheep who must be fed what they expect lest the whinge fest begin.
I have made 70/30 and 80/20 foils in the distant past, just moving the center line over and trying to lightly foil the smaller convex side, but these never seemed to have the responsiveness and projection of a flat sided rail fin, and are harder to make. They were however smooth and predictable in larger more powerful waves.
I am now just making my rail fins now with flat sides, not only as it is significantly easier, but they feel better, even though the flat sides make little sense from a design standpoint. I keep trying to get MrMik interested in designing and printing rail fins now that his large single fins are highly refined and reliable performers. I embarrassed myself when he referred to inside foils as 'cambered foils', and I was unsure what he meant though that the correct term.
The latest center fin I modified to fit Probox, I glassed over the 3d printed PLA with two layers of 1.43oz cloth and did two thick hot coats. I sanded it to about 85% in a rush, and went surfing in some very fun conditions, and the fin was almost always humming, each and every wave, 90% of the ride. Easily The most prevalent fin hum/whistle I ever experienced.
People I passed were commenting on it, as my hollow board helps that noise to resonate like a guitar. The humming on a few hard frontside bottom turns became ridiculously loud, then the tail started drifting shoreward with a loss of drive. I really liked the fin combo despite this. and just kept from pushing those frontside bottom turns as hard, then the wind came up .
Afterwards, I spent more time wetsanding the hot coat and sharpening the last 3/4 inch of its trailing edge.
Next session it was completely quiet, not a single humm/whistle, and I was not able to overpower it, but had few frontside waves and none of which allowed a hard frontside bottom turn in the flats, and the conditions were smaller/weaker. I cannot say the overpowering of it the previous session on hard frontside bottom turns was due solely to the humming/ inaccurate foil/fat trailing edge, but I suspect it played a significant part.
Pretty much every fin that hums, when I inspect closely and then razorblade scrape/wetsand on a block the trailing edge, the humming stops. I am not making it knife sharp by any means, just thinning out the last 3/4 to 1/2 inch of the foil and blending it into the rest.
I had the carbon TC redline center fin hum sometimes in my newest HWS, but it never hummed in any previous board I rode it in. When I sanded away some of those white and red paint lines to thin the trailing edge, no more humming.
So I'd take a close look at the trailing edge of your H2's. There might be a slight round near the trailing edge, from the spray on glossy finish they applied, that likes to form a bit of a ridge, especially if they sprayed it on thick.
I take fin humming/whistle as a sign something is wrong, and a few longboard fins, when they would start humming, the board would seem to go dull underfoot as long as the humming lasted.
When I was trying the injection molded wavegrinder winglet fins both the 4.8 and 5.7" deep ones, in my board they would also humm, and when the humming started I could feel it in my feet and the board would go dull. I was able to stop the humm by tuning the trailing edge on these too, but I never was able to click with those fins. I think the winglet angle needs to match the tail rocker of the board and then in certain parts of the wave it feel rocket like, but in other parts it feels weird and unnatural and kind of tracky.
The large wavegrinder WG2 fin in my one 9'3" longboard with less tail rocker, worked very well, but would track sometimes, it worked much less well in my 9'7" with more tail rocker.
Mr Mik made a printed version of the WG2, and I broke the winglet off hitting bottom. I rebuilt it with some Bubinga wood and changed the angle of the winglet so that it would 'dig' less, and that fin would be an absolute rocket in the trough trimming past sections on my bigger LB, where the fin whose winglet would dig more was rocketlike with the tail up high in the wave.
This inconsistency of the WG2 fin design became more noticeable when I started trying his turbucled fins, which did not seem to favor the top or bottom of the wave face, and were much more forgiving and predictable all around, but they were not as quick as the WG2. When I first tried his GullWhale design which is even higher aspect ratio, I was a bit blown away in that it not only turned well and was intuitive and predictable, but had the speed of the WG2 as well and not just iup high or down low on the wave face. Any other fin design ridden my LB is a tremedous let down now.
So this is why I am now so willing to try/experiment with designs so far outside accepted norms, and am becoming tremendously biased against the standard dol-fin shape the more I try other designs, as unconventional and as weird as they look.
I think the H2 fins have 1/16" of toe built in. The H2s will only hum when you engage them hard. I've had the same thing happen with single fins, where they will hum when I stomp on the bottom turn. The hum is more like a buzz. I also think it may be only on the lower cost glass flex versions I have. I think the fins I last used in the board with 5 degree FCS fusion boxes is made with texallium and they seem a bit stiffer than the glassflex version. Those fins are mediums and the glassflex are large, so there are several differences that may be why I hear or don't hear the buzzing. I also use them in my shorter performance boards.
This company in Indonesia makes the H2 fins in 3 sizes and you can get them in 3, 4, or 5 fin sets. I haven't bought from them yet. I got mine new from FCS and used from other people.
My brother gave me the Wavegrinder fins years ago, both the center and sides. I still haven't been able to get myself to try them, but one of these days I will give them a try. My brother said they work best in low rockered boards.
A buzz rather than a humm is strange, but it occurring on a hard bottom turn is pretty much where I now expect fin noises to appear most often and at their loudest. I have always, so far anyway, been able to stop it by tuning the trailing edge of the fin.
Regarding the wavegrinder fcs1 tabbed fins, they do sit a bit proud of the hull, and one can likely sand the forward or rear tabs to adjust the winglet's angle, though I am not going to bother. The 4.8 inch deep pair is not actually in my possession anymore, have not seen the guy in many months, and the 5.7's, the last time I rode it in my 6'11's center box felt absolutley atrocious, to the point I considered kicking it out shearing the tabs, and finishing the session as a twin, but the wind came up and I got out before I did so.
WG wingletted fins working better on flatter rockered boards makes sense and is my experience with the larger WG2 on 2 longboards, and the 3d printed clone whose winglet broke and I modified its angle when I replaced it.
The 50/50 foils of the WG fins, as rail fins, might be part of the reason I do not like their feel. Perhaps they need zero tow in and zero cant...... Either way I so much prefer the feel of the other fins I have been experimenting with, and am not too stressed if I never again see the guy to whom I lent the 4.8's, and if someone wanted my 5.7's, they'd get a deal on them, as long as I don't have to go to the post office. As far as the large longboard sized WG2 goes, it is too flexible for me, and Mr Mik's turbucled G-whale fin outperforms it in every way by a significant margin.
The WG fins started my whole foray into High aspect ratio, and the ensuing joy, so I am thankful for their existence, but the winglet has a narrow sweet spot in the wave where tail/hull rocker and winglet align to give that drag free feeling burst of speed. The WG2 also feels like it sometimes dictates the line taken, causing me to go further out on the shoulder before being able to turn. It does however feel really good on the downturn from high up in the lip accellerating almost unnaturally into the pit. I'd certainly be riding it often in place of my regular Dol-fin in my LB, if I did not have turbucled Gwhale fins which are speedy happy go lucky frothers themselves.
Every time I start making new fins, it is as I forgot how labor intensive they are, especially when making a pair of rail fins and trying to keep them symmetrical.
Below left to right is the recycled 3d printed 0.45GWhale fin, whose tab I just extended to allow it to sit further back in the board, a FCS 'rusty' fin from teh 90's, my latest unfoiled cedar sharkyhars, an the purple fin is Mr Mik's Albatross whale fin cut down in size to fit probox. This fin needs to sit further back on the board by at least 1/2 inch and will get modified as the 0.45GW did.
Very much liked the 0.45GW with larger sharkyhars before I modified the tab, but it was not enough fin with the smaller sharkyhars. The 0.5GW's felt much better with them, sitting 1/2 inch further back and being slightly deeper.
My sharkyhars are deep fins, as is the purple 0.5AW fin, but they feel less draggy than the Tc redline sized normal fins and certainly pivot faster.
Sorry havent been here for awhile setting up a new fin factory in the last year. Alot of Changes happening to better service the Industry. The Probox Finsystem site is old and being reworked. To better serve you my friends. Probox Finsystems products are exclusively available at FiberglassSupply.com or you can check Probox out on Facebok "Probox Finsystems" or Follow me on Instragram as "LAFINS" Thanks for the years of support and look forward to new stuff with Probx Finsystems.
Yes Fiber Glass Supply will be in stock by this weekend on ProBoxes. Much Mahalos my friend. LA will never let you down.