Fin placement on fishes? quad or keel

With regards to fin placement, I’ve seen keels and quads set all the way back past the notch of the swallowtail and then seen them 3+ inches forward of the notch?? What’s the deal? Is there any obvious explanation? thanks

The obvious explanation is that there is no standard depth for swallow tails. If the swallow is 3" deep, and the fins are 3" fore of the notch, the fins are at 6". If the swallow is 8" deep, and the fins are lined up with the notch, the fins are at 8".

I usually set mine somewhere between those two, as do lots of others.

I line up my keels with the end of the crack. Usually, between 5.5 and 6.5 inches from the tips. A three inch crack is probably a swallowtail. With the Pavel quads I think of them as split keels and place the rear fins even with the crack as with keels. Don’t remember the front fin placement. I can measure if you want exact numbers although I think my placement is a bit farther forward than recommended on other post. I have no idea about other quad placement,but I’m sure it’s all in the archives. Mike

Rooster thats basical what I do. I like the fins either inline with or 1/2- 1" forward of the but crack (dependign on the dept (whis is also usually 5.5-6" deep). I usuall put the keel fins trailing edge 1 1/4 from the rail and I design my tail template so the the trailing edge of the tin is in line with the tip of the tail,

Not many shapers have done more research on quads then Mckee in Australia. His website gets very precise on measurements and fin results…