does anybody have an opinion on how these fins would work as a twin fin set up on the 6.6 pictured below them? i want to hack a swallow tail into the 6.6 too… this stuff is just junk laying around the house (or is it “vintage”?) and i like to waste my time on cantankerous endeavors. i understand that there is more to a twin fin than a swallow tail, but i’m not quite clear on what that is yet…
I suppose that Bill Thrailkill will give you his advice much better than I, but I seem to remember Bill using the old Brewer fin template and this one isn’t very far from it. So, it should fit OK. But I have already seen better foiled Rainbow fins, IMHO.
those fins look similar enough to each other that they probably WERE in a twin fin some decades back. Dig around in old surf mags or the australian web page about surfboard history, the original twin fins had issues but they were Loads O Fun and I’m surprised they haven’t been one of the retro-crazes again - or maybe they were and I just missed it. Find yourself a vintage twin fin board at a yard sale with a pair of short boxes in it, and you’re in business… or try Bill’s trick with the two boxes near the stringer, what the heck… its just surfing.
i think they were used on an old wind surfer as stabilizers.
i was just going to glass them in after i hack the tail… but i suppose boxes would allow me to put the fins back on the shelf for an archaeologist to ponder one day.
I built hundreds of twin fins in Santa Cruz during their late '70s-early-'80s revival and exclusively used Rainbow Fins. Their factory was right down the road from me and I still count the DeWitt family as friends. Most of the boards were made with glass-ons for light weight and strength. The fins in your possession could benefit from a foil tune-up. Don’t be afraid of losing the outer color lam in order to thin them for weight while smoothing out the foil. IMO keep the double foil, they work great in twins if you position them correctly. Make sure they are canted and toed!!!
Before you do that, take the better-foiled fin, put it in the center box, and go surf that board. It MAY work just fine that way. Then go ahead and grind off thr glass ons, cut the tail, refoil the other fin, and install your new fins…and reglass the tail. Seems like a lot of work to me but if that’s your plan more power to ya. I’d go with a swallow tail rather than a fish type tail myself.
You might try using some balsa tailblocks glued to your tail cuts (if you do the straight V shape not the curved one) so that you can taper the deck line down better? Hobby shops sell little blocks of balsa so not hard to find, easier than cutting back the deck glass and foiling the deck down that way.
i have surfed the board with one of the rainbow fins maybe 10 times at the more mellow north shore breaks over the last couple years. it’s “bucky” or “bouncy” and slow. the board is about 3 1/2" or 4" thick… i think the thickness makes it so “bouncy”, (but i’m still learning here) BUT it’s sooooo easy to get in early! the extreme cant and toed in position of the fins maybe slows it down? or maybe the boards lack of speed is due to the general rail shape? it’s kind of down railed… i think. i dont really know what a down railer is. heres a photo of rear part of the rail. the front part of the rail is down hard too, and the middle portion is down but not so hard…
ha-ha. yes, it does seem like a lot of work to make a silk purse out of a sows ear. i found a can of UV resin and some 10 ounce and the fins in the shed one day last week and then remembered this dog of a board board that paddles really good… i have never shaped a board of my own and my funds are very limited. this seems like a fun way to learn some basics. you know, make it, surf it, figure out what might make it better, make changes, surf it again, etc, etc.
great idea about the balsa blocks BTW! but they are not free (like the rest of my supplies) so i’ll save that trick for a more serious project.
I traced your outline and threw in a swallow for shits n giggles…actually looks pretty sweet. Speed dialeresque. If you decide to do it i’d grind those fins off and use a fin system.
Howzit Keith, I had a whole lot of those fins and I mean close to 50 of them in a box that I had put away back in the early 80’s. They were a great fin for single fin boards due to the wide base, but they are also a great fin to reshape. I made a bunch of small center fins for longboards and every body I gave one to really liked them and if my memory serves me right the were a Brewer template. I would reshape them down to any where’s from 51/2" to maybe 6.20" and whe you’ve got side biters they work unreal. Aloha,Kokua
well, you seem to have the right attitude for the project, and the board has some v in the tail, so it might work. Grind off the old suckers, cut down the tail, try to foil it out a bit, and like Mr. Vet correctly pointed out, twin fins need both cant and toe in. How short is your board after choppage??? I’d say look at about 8" up, an inch off the rail at the back of the fin, six degrees of cant and toe them in so they point almost at the nose - but without looking at the rocker & stuff it’s hard to say. Tack them on with hot glue where you think they should go, and see if it looks like a surfboard to you… it’s gonna be a crappy old board no matter what you do, but its fun to play around! Oh yeah you ought to either refoil both fins so they are the same…
the board is a 6.6" now and the hack job will take it down to about a 5.6" if i’m feeling frisky… heres a photo of the rocker.
(slightly exaggerated by a wide angle lens, but not much.)
i surfed it yesterday at lani’s in knee to waist clean surf. i want it to surf better on days like this. the board just has a real hard time digging a rail… heres a crappy photo of the rail. any theories anyone?
thanks for all the advice! this is fun. and kokua, i think i will take your advice and save the rainbows for longboard skegs. it’s too bad i just sold my pulled in george ku 9.0"…
also… does anyone know anything about “nicholes hawaii” the brand? i see them around sometimes… in the yard sales, in the used board section of the lesser known shops, in the trash ;-), but i never see anyone surfing them. ha-ha.
thick boards will do that… corky overall (you said 3.5 to 4 inches thick?) and still thick at the rails, so hard to bury them. you could try to harden up the rail line in the back half of the board if you are hacking away anyway by putting a bead of resin around (or bondo, ask the Hull Guys about that one) and sanding down to a sharper, hopefully friskier bottom edge. For a twin you’ll want some bigger fins too, not the normal thruster size you’ve gotten accustomed to seeing. Have fun with it! Do a little research into the old twin fins and you’ll get some ideas. Or look at how Greg Griffin and others do them today. To my recollection the old twins turned good but had a very loose, about to cut-out on you feel, and given the vintage/thickness of your project board, that’s what you should probably be expecting (at best).
One possible reason that board is a dog to begin with coud be too much nose rocker (once again I am just guessing based on the photo) and by cutting a foot off the bottom you won’t be solving the problem. If it were me, and the board is as thick as you say it is, and if you wanted a project to learn from, I would strip off all the glass, plane out some of the nose rocker, cut it down to size, add some tail flip and re-glass if it turned out the way I wanted. but, then again, you should probably just buy a new blank at that point.
hmmmmmmmmmm… you make a good point mahana. she could be slow because she is plowing too much water. combined with the the thickness this could account for the “bouncy” feel of the board too i think… all along i thought the tail just wasn’t holding. if i only had a plainer. actually, the board so many serious dings that i doubt the foam would yield enough usable volume to make it worth a total reshape. thanks for the input!
Yeah I had a late 70s single fin that looked like those! I dont use them today though. Refoiling sounds like a good idea. Looking forward to the update!