Help with quad fins configuration

Hello Everyone, I'm shaping  this board for a very good friend of mine and I don't absolutely want to set up fins in the wrong position.Is there anyone who can help me with it?Thanks a lot

I forgot to say, just in case it wouldn't be clear on the picture, that it's a 6'2'' x 22'' x 2 1/2''

And width at 12'' from tail is 17 7/8'' and at nose is 15 9/16''

His tail width is a whopping 17 7/8" wide. 

I’d say this width would work better with  fins closer to the rails… Say 1 1/4" off the rail for the fronts and anywhere from 1 3/8" to 2" in on the back set (measured from tailing edge of fin to rail edge)…

This is a wide tail for a 6’-2", and might require some thought as to what the main ride goals are so you can locate the fins accordingly… I’ve never built this wide a quad, so I could only guess…

I use different setups with quads depending on board type - the mackee data for shortboard/fish hybrids

and then my own placement for retro influenced fish where I'm simulating a keel with the quad - sort of split keel if you like - I've done quite a few of these with dimensions very close to yours using Pavel Speed Dailers - let me know if it's this kind of thing and I'll pass on the detail.



Hi Rich and thanks for passing me those infos. I was wondering if I better set the back fins up more in the middle or along the rails.I have a very little experience with quads.On my previous board i added a double concave but on small waves it feels like creating too much drag and suction.Do you and other guys think that the board i'm making needs any concave or i can just leave the bottom flat as it is?.We're surfing very mushy waves most of the times so what i need on this board is speed.Thanks again

I've been using a single concavethrough the board for the past few years - often used in mushy waves and they work real well - I made a few flat ones to start with but they felt a bit 'slipppery'. The you'll get the speed from the flat rocker,width and to an extent the volume of that need to worry about the concave slowing it down.

More recently I've moved towards a single with a deep bonzer style double - this has proved to be real successful on steeper,suckier waves. Still bags of speed but great control at speed.

I set my speed dialers at:


Trailing edge 11 3/4" from tail

1 1/2" from rail

1/8" toe in

8 degrees cant


Trailing edge

6 1/2" from tail

2 1/8" from rail

1/16" toe in

6 degrees cant


Seems to work with the speed dialers...

Hope this helps




move em in off the rail for more lively feel and less tracking, easier to adjust thru turns, whereas on the rail they seem more drivey but tend to wanna stick to their much more drawn out lines ( sometimes feeling tracky ) but the set up out near the rail can feel more stable and suits less skilled surfers.....I do a design called the Fat-Bat which used to be out on the rails but after trialling different set-ups and shaping a few boards for Nick Carroll, we moved the rears in off the rail and they are going insane...but in saying that, tails widths are between 14 1/4" and 15" depending on board length....

off the rail rears...[IMG][/IMG]

on the rail....aqua quad [IMG][/IMG]

and Mckee, best suited to narrower and high perf shapes...[IMG][/IMG]

Off rail and back (a la mckee): it’s more thruster feeling, good for top to bottom surfing

Near rails : lot of grip on rails easiest to go on rail but less control in transition and off the top, good for speed in trim line and cutback.

It’s just what i feel for my test.

Sorry for my frenglish

wherever you put em, you are gunna want a decent amount of fin area for such a wide tail, maybe pull it in in the tail, quads can slip and slide when too wide, great fun for trimming in fattish waves but when it stars to suck and have some push, they will slide unless you have big fins, then they may feel stiff.....just my thoughts.....maybe pull tail in 2" and see how she looks ?????

Thanks Guys! I made the tail a bit tighter ( i will post some pics soon ) as after cutting the outline it did look far too wide to me and i made some more little adjustments, now it looks perfect.I was wondering what would be the effect of a very sharp rail edge until the rocker apex which is approximately at the midpoint...would it release the water better?would it make the board less slippery in fast turns?I tried a few days ago a xanadu fish 6'0'' x 22'' x 2 1/2'' keel, which had this very long sharp rail edge and after the rocker apex the rail lean into the bottom of the board just a little bit (i don't know if that makes sense)...the board felt much more stable in tight turns than normal keels.Am I wrong?

Does anyone have an answer for my last question?thanks

are you talking about a "tucked edge" ?

a sharp edge that's tucked under the rail a little...

No i mean 90° sharp edges


No i mean 90° sharp edges


wow, really?

and how far up from the tail do they go?

Sharp edges release better, which is the opposite of what you want, if you’re looking for more hold in a turn. 

Shouldn't they bite the water better ..?

no, water sticks to soft rails and release right off hard edges.....

^Correct,I made a board last year and left soft rails all the  way out the tail,it was a 6’6"quad.I surfed it for about a month like that,kinda slow and lacking drive but it was a good shape and fin setup.I read a few things about rail designs and decided to add the hard 90 starting about 18" up from the tail blended in.It was a night and day difference,the board got very fast.You should try it,it’s a trip how different the board rides with and without hard edges in the tail.

Here read this.