I was wondering if anyone knew what kind of fin is used on the single-fin fish that channel islands/rob machado makes. It looks large like a longboard fin but has quite a different shape. thanks
Yah its a really up right fin, the base is on the wider side which is appropriate to use allong with the wide tail design of that board. a TA norm flex is also used on some. Cool board. I see a lot of people on single fins with really pulled pinie tales in small surf , whats up with that, ? the Rob single fin is made by Fins ultd.
http://www.finsunlimited.com/fins/rt_s_channel.html http://www.finsunlimited.com/fins/rt_s_channel.html 
Looks pretty much like a Greenough fin. I’ve heard stories of Merrick copying templates at the Ames factory.
Thanks guys
well, the 4C showed up, as well (on the left)
i’ve seen one of his boards up close and the first thing i noticed was the fin- it was the Greenough pictured with some of the tip are ground away, which is probably the template Al used to make the ci fin pictured.
An approximation of the outlines at the same size 
Uumm, did I get the wrong TA fin??
That’s pretty much the same.