Changing Stiffness by Changing Structure

Every time we print a blank, Mike and I tweak the structure a little bit. We add a stringer or two, we change the thickness of different parts by a fraction of a millimeter, or we change one of the settings of the printer. We figured out that once the holes in the structure get too big, we can’t make the glass job smooth. Because of that, we figured out a minimum number of “diagonals” that each board needs. The diagonals, though, aren’t really very stiff. So, we’ve been experimenting with different tweaks to change the stiffness of the blank, and then testing the final boards to see how they surf. The quality of our glass jobs has gotten way better, but we’ve been keeping the layup pretty much the same so that any performance differences are coming from the core structure. We even benchmarked everything against traditional foam blanks.

So what did we figure out? Well, we can change the stiffness of the blank in a ton of different ways. Making the stringers thicker works, but it makes the board a lot heavier. Moving the stringers next to the rails gives the board a lot more torsional rigidity and stiffens up the rails, but the board will still flex a ton from nose to tail in response to pressure from the surfer. Changing the angle of the diagonals can increase longitudinal stiffness a lot, but it decreases torsional stiffness and makes the board feel less responsive, like surfing a piece of wet cardboard. In the end, we settled on a design for our Sea Mink that we think maximizes responsiveness and minimizes weight. But we are super stoked to run custom prints for lighter or heavier surfers (me and Mike are both about 200 lbs), or to use what we learned on other shapes. Eventually, we will be super stoked to see if our printed plastic structures can offer pop like a carbon stringer, or absorb the slappy chop the New England’s howling winter offshores usually create.