We want to share a neat project that most everyone with a thin skimmer can use, but before we do, we wanted to give you the link to the sequence shots of James Walker Landing that Frontside Big Spin to backside Body Varial. We know that many folks study all of James’ videos and pictures to learn new tricks, it’s like an online coaching session! Use the blue link in this sentence to go to the Flyboy Flickr album for your study session! Good luck, we hope to see a bunch of folks doing front bigs this season, after first studying James’ landing that trick.
We apologize for being tardy with posting those sequence shots! It’s been a wild couple of days! So that wasn’t what we wanted to share with everyone today. We recently damaged an older Inland Surfer Skimmer and decided to perform a modification that can increase the performance of a bunch of thinner skim style boards. We’ll show two pictures, sort of a before and after so that you can see what we hope to get to. What we are doing is installing what we call a torsion box inside the damaged Inland Surfer.
This is the board that was damaged. It is probably the most popular skim shape that Inland has ever produced. It is the basis for a bunch of different models.
What we are GOING to get to is this stiffer and more “poppy” modified version, that includes the installed torsion box and a carbon tape cap outside. We aren’t going to paint over the modification, but you could easily to hide the modification if you wanted.
If you happen to have one of the thinner skim style boards and maybe even some of the compression molded surf style boards you may have felt they were slow. Now we’re sorry to tell you that LOTS of the yokels out there that have more ego than knowledge will tell you that it’s rail shape, or outline or any number of things, but honestly, many times its associated with unwanted flex, especially in crappy construction. Those boards, when ridden by someone outside the weight range or when they are riding hard, will experience flex that causes the rocker to change. That change creates this almost plow like effect as the board is moving forward and hence slows them down…now if your wake is all pushhhhhhhhh going forward it will never matter, because you also have a magical unicorn helping you with ballast! For the rest of us, since there is not one single foot of water travel forward, that flex is like cutting the effective surface area in half…or at least down significantly. As your board plows through that water traveling UP the wake, it feels like you are dragging an anchor. This is your fix. Sadly, compression molding has been given a bad rap by those same folks that don’t understand construction or board design. Slapping a torsion box in most of those older boards, will fix many of them right up. It’s not the process of molding that is the problem, it’s a poor design.
We’ve talked a number of times about how the thickness of a wakesurf board dictates the stiffness, in fact the amount of stiffness is exponentially related to the thickness. For example double the thickness and the stiffness increases by a factor of 4. Obviously we can’t really effectively increase the thickness of an existing board, so another way to increase stiffness is by tying the bottom and deck together with a solid structure. You’ve seen this done with wood stringers in surf board blanks. Really thin boards in the 1/2 inch or thereabouts range probably aren’t really appreciable stiffened with a small section of wood, as it’s easily bent. So what we are doing is installing an after-the-fact stringer’ish arrangement that we have termed a torsion box. It is 5/8″ thick, surrounded by carbon fiber and attaches both the deck and bottom together.
Carbon fiber is stiff material, but it’s often inaccurately referred to as stronger than steel attempting to give you the idea that super thin layers of carbon fiber are stiffer and stronger than a steel rod, an inch thick. Technically, carbon fiber is stronger and stiffer than steel in the exact same thickness, but a tiny little fraction of an inch thick of steel can probably be waded up in your hands like aluminum foil. So sure it’s stronger and stiffer than something you can wad up in your bare hands. So what we did was surround a really wide piece of high density foam, such that we have close to 5/8″ of carbon fiber in all four directions surrounding a box-like structure.
What we did in short, was route a slot down the middle, wrap a section of high density foam in carbon fiber and stuff that in the slot we routed, combined with a bunch of epoxy to stick everything together!
So you saw the board we started with, the next piece of material we will need is some high density foam. You could also use a small section of wood just as easily. All it needs to be is something stronger and stiffer than the surrounding material in the existing board. We had a scrap section of Divinycell H80, so we grabbed that. Now we should note, you don’t need to run the torsion box all the way from the nose to the tail, just through the majority of the length and that will prevent virtually all flex when riding.
We will be routing a long slot in this board and we want that slot down the center, so we mark a center line as a reference point. It’s possible that you could install two stringers somewhat offset from center, in this instance MORE is always better.
As we mentioned, we want to route a really straight line down the middle of the board. Our router had about a 2 inch offset from the bit to the outside of the flange, so we measured and marked a separate line. Then we will use a straight edge, in the picture some aluminum channel and clamp that to the board using bluw irwin clamps.
Very very carefully, we’ll align the router with our straight edge and then route the slot for our torsion box. We should mention, set the depth about 1/8″ less than the thickness of the board. You’ll dig the last little bit of foam out by hand, which isn’t a deal, but routing through the deck will be a huge hassle and probably isn’t even worth trying to fix at that stage. So route about 1/8 inch less than the thickness of the board.
Ok, so that is all we have time for today, we’ll come back tomorrow to show you the rest of the steps.
Thanks so much for following along, we really appreciate it.