retro fish fin placement

On a retro wide split tail 5’6"fish how far up does the trailing edge of the twinfins go? Does anyone sell those keel fins that were used back in the early 70s ion fish? Thanks for any help. Bob

The original keel fins fins are at Mitch’s in La Jolla or the Green room in Ocean Beach, San Diego. Using the new and Improve archives you will see there is no fast and ready answer to the trailing edge question… . Good Luck

I was looking at some pics of retro fishes and noticed that most of them have their keel fins as far back as the depth of the swallow to a couple inches forward of that point.

I’ve been designing, building and testing what you are making for almost 30 years now. At this point, your fin placement will depend upon rocker as well as outline. My guess is that you used a 6-2C with natural rocker. In my opinion, this is a bit too much in the tail BUT if that is what you have, then I recommend going 1/2 to 3/4 forward from the standard position. The standard position tends to be like you deduced (about 6 inches from the tail tip) or even with the split of the fish. If you are making a purist version then the keel fins (8"+ bases) would probably be best set parallel with the stringer. With all this said, there are so many permutations that are also valid that you can alter those things that I have found to work and still have a decent functioning board. It is also my opinion/finding that the fins do not have to line up with the tail tips, ie: a 12" tail span would make a fin placement 6" out from the stringer; rather, the keels function well about 1" in from the rail as measured at the rear of the fin regardless of the “tail tip line”…