Help with Quad fin setup for a Chubby 6'1"

[edneileoni]

Hello Guys! i`m from Brazil and new on this forum.

First of all, my english is not so good, so im sorry if im posting on the wrong section pr if i dont make myself clear.

I walked in this adventure of making my own board and i have no experience on doing that, and now i need help with the fin setup.

I searched a lot in the last days on this forum for quad fin information, and found a lot, but i have no experience, and sometimes i get a little lost in the infos because i cant understand  it very well.

I found the mckee formula for shotboards http://www.mckeesurf.com/?page_id=267

and i found the Robin Mair setup https://gearbox.surf/manage-assets/PDF-FILES/HFINS-QUAD-Layout-2018-PRINT.pdf

i was searching abot toe in, and some say that the rear fins need to be a little less toed that de front ones, and some say that fronts and rears with the same toe is better.

I`m pretty lost on what to do, so i decided do post my board details and in what conditions it will be used, to see if you guys can help me.

The board is a hollow wood (paulownia) 6’1" X 22" X 3" with 1.5 tail rocker and 3.8 nose rocker, 47~48 liters, Tail (@ 12") = 17" and nose (@ 12" from nose) 17", i am pretty heavy (230lbs) and a hobby surfer, so i dont do fast and vertical maneuvers, just some bottom turns and carves, floaters, enjoyng fun surfing. i only go to beach breaks, and this board will be used on lazy days, with weak and fat waves, and up to head heigth.

i want a board that i dont need to be changing rails like crazy to speed up, or doing so much effort to not stall the board, and i dont know what fin setup will be best for this.

So, if someone with more experience than me could help me on this, i`ll be gratefull!

some photos of the board and a “diagram” that a draw with some starting points…

[JohnnyK3]

Here’s one of my boards that’s pretty close to your dimensions in that pic, it’s 6’0" x  22" x 2-3/4". The front fins are at 11" from the tail and toed in 1/4" (1-1/4" off rail) the rears are 5-1/4" from the tail and toed in 1/8" (1-3/4" off rail). I’m around 210 lbs. and surf similar conditions you describe and it goes really well.

Those measurements are pretty much the Mckee dimensions and it works well but I like to have the fins further out on the rail compared to the Mckee set up. I think Robins fin cluster tend to be a bit further up with a dedicated quad compared to most five fin setups where the fronts are further back so it can be ridden as a thruster as well as a quad. 1/4" toe in the front and 1/8" for the rears is pretty standard at least for the production boards I’ve had.

[Huck]

This is from Greenlight surfboard supplies

[lemat]

what i would do for this board in millimeters :

front : 280 from tail, 27 from rail, 6(from center line) toe-i, 6° cant

back for down the line surfing ( front foot riding in fast hollow projection wave) 140 from tail, 30 from rail, 5 toe-in, 3° cant. i would add a center possibility at 80 from tail for thruster option or nubster stab.

back for top to bottom surfing (back foot riding in flatter lower projection wave) 120 from tail 50 from rail 0 toe-in 0° cant. play with fin size and profile to tweak feeling a bit.

[Smerk]

Plenty of options and will all ride well. Here’s what I did for my small wave quad 6 X 21 X 2-5/8. 15-3/4 Nose, 17 Tail and flat with 3-3/4N and 1-3/8T rockers.

Quad fin placement – Front 11” up, 1-3/16” off rail. Rear fin 5-1/2” up, 1-3/8” off rail, no overlap. Both ¼” toe in.                  

I’m mainly back footed. Rode 1 foot beach and almost double over reef, couldn’t believe how well it went.

[TaylorO]

+1 for Robin Mair’s set up.

[TaylorO]

+1 for Robin Mair’s set up.

[gdaddy]

With quads, big guys (190#+) often tend to favor single foiled rears set at the rail.  They have the leveraage to move a lot of fin area.  Smaller guys tend to favor the rears set futher inboard off the rail and the asymmetric foils.  Your template already has plenty of curve through the back quarter so control isn’t going to be an issue for you.   I think McKee’s setup is aimed at making a quad feel and handle more like a thruster and less like a twin.  Others may disagree.