Finterview: The Phi-n and The Flowthru

Many months ago, while visiting my infamous friend Mike - math teach, father, friend and fellow swine slider - I asked him about a board I'd seen on his blog, something he called Blackstoke II. It was a pig shaped by Marc Andreini with a traditional style skeg affixed to the far end. Only this skeg was hollow in the center - a "flothru" fin Mike informed me. Obviously interested, Mike explained its origins, described how it surfed to the best of his abilities, etc. The next time I was in town, Mike laid a blue folder on his kitchen counter - inside was roughly 1,500 words regarding 'The Science of Surfing.' I won't divulge too many details, as I believe this story will find its way into a surf publication sometime soon, but what I can tell you is that tucked into the back of the folder was a sketch of a skeg, affectionately named 'The Phi-n.'

Math equations danced around the drawing. Mike had even cut one out of graph paper, and placed it atop a tracing of another skeg, so that he could describe the differences more effectively. And so that I could see. His 'Phi-n' was shaped using science, er, math - whichever. The conversation took a turn, and then Mike disappeared into another room to nap with his daughter and three of his five dogs. I was intrigued. A few weeks later Mike sent me a message: "Matt is making me another Feral Pig! It'll be white, with a big yellow cigar stripe and a fin-box." Wait... "A fin-box? What the fuck for?" I asked. To which Mike replied, "You'll see." And then came an image on Instagram. A snap shot of David and Mike's collaboration - two fins, each extraordinarily unique. I've asked Mike to give us a bit more info about both. Follow the link to learn more.

The Flothru: According to Marc Andreini - designed in 1964 by Jeff White of Owl, this design was an attempt to reduce fin area on a D fin to make it easier to turn and go through white water. It is my experience that this fin has a larger turning radius than the Phi-n. I notice the feeling of the Flothru most when I am experiencing a directional change. While in trim, the fin does not feel significantly different. The Flothru has plenty of drive off the bottom, yet it seems as though it doesn't push back as significantly as the Phi-n. the Flothru is a rad fin to have in your quiver.

The Phi-n: An experiment in mathematics. I see math everywhere. I see D fins too. Eventually my mind saw a D fin designed by the Fibonacci sequence. I drew some squares beside squares, then passed some curves through the squares... A gorgeous D fin template was staring back at me. My buddy Dave Town built one. It felt so powerful and solid. A surprise to me. I had no idea what to expect when I let math dictate design. I do not believe there is causality here. It's a shame more of the surfboard manufacturers don't admit their pseudo scientific marketing platforms.

You can snag both of these David Town x Mike Black fins HERE.