I’ve been going through the archives looking for help as to where I should place my keel fins. The problem is there seems to be a wide range of suggestions as to what will work. I’ve been collecting this info trying to figure out what would work best for my board and fin specs. Here is a general summary on what is out there. 7" keel fin, 10 1/8 from tips 1" from rail 3/8 toe 71/4" by 51/2" keel fins, 81/2" from tips and 11/4 " from rail 1/4 toe 4degrees cant. skip frye specs, 9 1/4 by 4 3/4 keel fins, 63/4" from tips 6" from stringer no toe no cant. This was for a board with 161/2 " tail Rule of thumb, 15" from tips to front of keel fin, which in my case puts my keel fins around 63/4 from tips like above. 8" from tips and 11/8 from rail So as you can see there are a wide range of fin placement ideas out there. Which make sense to go with the varying board dimensions and keel fin dimensions. The part that throws me is the big difference in the placement form the heel of the keel fin to the tips. Anywhere from 101/8" to around 6". That seems like a big difference in how a board is going to handle. My fish is 5’9" N 163/4" W 21" T 161/2 2 3/4 thick 6" deep swallow. N rocker is about 31/2 and tail around 13/4 I went with a flat bottom. My marine ply keel fins are 8" by 5" they have no rake. I was thinking of going 63/4 from tail and 11/4 from rail ( the skip frye specs). Still undecided about toe and cant. I looked at alot of traditional fishes this weekend with keel fins and almost all had cant and at least half had toe. Which I thought was weird because I read somewhere that toeing keel fins was counter productive I also spoke with a shop owner about fin set up and he said I should go 6" instead of 63/4 from the tips because my keels had no rake. Why is this ? the only cant measurement was the post using 4 degrees. Is this standard. I know this is a reoccuring thread but I hope to get some good information in one place for myself and the hundreds who will follow looking for help and peace of mind with there keel fin set up. Thanks SR
…First,before I blindly answer your question(s),what size and dimentions are you looking at?Also,what do you what the board to do?eg.flat skate.bigger wave rider,smaller wave,mushy,throwing,etc.How much float and paddle are you willing to sacrfice?Answer these Qs and I’ll get back with you. …A Fish for the most part is easy to shape,a few easy to follow rules,The one rule that I see broken the most is the"OVER SHAPING"rule.Herb
Thanks Herb, Just before starting this board I checked out some Brom fish so I was inspired to leave the thing as thick as possible. It’s 5"9" and I just skinned the blank and turned the rails. I did the most minimal foiling using 2" thick rail bands. Riding style, I would be happy to have it handle up to head high. I don’t expect it to go vertical or into giant surf I have other boards for that. I would like just enough turning radius to do some classic figure eight surfing. My main concern about getting the fin setup right is I don’t want the board to be tracky. As a fellow old school skateboarder there is nothing worse then being on a home made deck and not having the trucks aligned properly. You can still kinda skate but when you least expect it the thing goes straight when you were thinking turn.
…If a Brom type is desired,I would go with what we called in the mid-70s a “hatchet” rake fish fin.This one worked the best for me,using that design of fish. …settings 7.5 up,toe to the nose or 6"past the nose,5-6 degrees of cant.Trailing edge 1-1/4".Herb
Thanks Herb, the bummer is I’m already stuck with 8" by 5" marine ply keels. They have no rake. If you got suggestions with this type of keel fin on my board It would be much appreciated. If this is going to be a more down the line set up so be it. It all sounds like speed and fun. Board dimensions 5’9" by 16.75 by 21 by 16.5 by 2.75 thick with a 6" deep swallow and flat bottom 3.5 n rocker 1.75 tail. Ps Herb, you were the first one to help me out three years ago. Now here you are today more then anyone else still stepping up to the plate. Thanks alot SR!!!
6 3/8" is what my 1973 Fry fish is set at(for a historical setpoint) with no toe in and no cant out, double foiled Gephart wood+glass keels. Now in my mind this shape isn’t doing it for me and probably is more for a knee-boarder at 5’9" but it also is volan glass and probably classic weight foam. Toe-ing in 1/8" and that 4 degree toe is what everybody that rips on a fish around here is using and we still use the gephart keel fins. Now getting pretty vertical with off the lips and such. I also wanted to put keels up further like 8"-9" and was talked out of it by the Fry homeboys. Your forward pumping motion is aided by ‘slight’ toe and cant with those double foiled keels . I ride them. Keep them under 6’ with no vee with symetrical rails in the forward 2/3’s and you’ll have fun with your creation. Funny, in around '75 we quit using keel fins and slapped a 10.5" box in the center with a 8" brewer dolphin fin and the same fish outline and bingo!! all the sudden we could do much tighter cutbacks instead of roundhouse cutbacks!!. So we called it a ‘summer fish’ and G+S glombed on to it and made all hybrids, the keels were gone after that, now they are back and expensive, what a trip.
…If you plan on using those keels 8 x 5s it’s going to be stiff(for me anyway).A little toe and cant will help this,as well as moving them up 7" , 7-1/2" from the tips.Will it spin out? Not with those fins!!!..Keep Building!Herb