6'0 single fin bottom shape help

I just finished shaping a 6’0’’ x 19 1/2’’ x 2 1/2’‘. 15’’ nose/tail. the rocker’s fairly flat. It’s got a pintail and Im probably going to use a 8.5’’ fyre flex fin on there with the box 5’’ from the end of the tail. Im making it to surf some clean big fast down the line type waves. I been doing quite a bit of research on the forum searches, but I still can’t decide what to make the bottom shape. I was leaning towards a slight double concave to spiral vee, but I’m not too sure how well that would hold in overhead+. Can I get some help on this?



Single to double works very well but vee to double goes great also. just go mellow though on the depth and you’ll be fine.

when you say vee to double. do you mean double to vee? if not how does the vee to double work?

How big waves?

What kind of rails?

Check out the Machado single fin Merrick does. That bottom works good in waves up to head high or a foot or two overhead.

wave size : headhigh + biggest I can paddle into with a 6’0

rails: down rails

on the merrick single fin, I was inspired to do something similar to that design. I was wondering what kind of bottom that board uses? I ve been searching forever without success online. I’ve ridden a 6’0 flat bottomed one, it was ok…only if it was shoulder + and clean. I have a shallow single to double 5’8 keel fish that I love the rail to rail pumping action.

The main bottom feature in Merrick’s “Rob inspired” single fin is two deep concaves (spiral vee?) that run off the tail with a hard, untucked all the way around a full rounded tail. Full down rails, wide, flattened rocker. Wide point forward. You could use a fish blank. A 6’0 would be about 20 inches wide… maybe a hair less. Stiff, slightly raked, but long single fin. A glass-on would be sweet, but Merrick puts in a box. Check the MSF and the MSFG2 on the channel islands website.

thanks for the help! I already stripped a larger older retro board and shaped the board a few days ago, I have about 19.5 wide and 15’’ tail and nose, just the right amount before it’s too thin. Everything’s pretty much shaped besides the bottom shape. I was leaning towards the 2nd generation of the msfg’s. I got some spare glass and epoxy, so the board’s probably gonna cost 60 bucks at the most, el cheapo for the win!

Right on…

The 2nd generation looks like fun. Same bottom as the first generation, but pulled rounded pin and pulled nose… a bit narrower, too, but still wide. I think 19.5 will be a good width for you…

…and glass that fin on!