Dynamic wakesurf board bottom and no Koocanusa coverage

We had hoped to have some sort of details about the goings on at the Koocanusa Wakesurf Challenge, but it looks like we’ll not have any details until Monday when the folks get back on US soil. The area is a little isolated and apparently the international per text message rate is one right arm and one left leg. Sometime next week we’ll get some details!

So back to our build and we will be doing some wakesurfing over the weekend and hopefully Monday, with our friends Eric and his family and then the newest Victoria skim Team Rider Mitch Lemos. We want to get Mitch’s 3 shuv on video, we disappointed ourselfs by missing that!

You’ll remember that we wanted to try and develop a dynamic bottom on a wakesurf board, such that the rocker and the concave could adjust to some degree to accomodate changes in the wake, possibly different wakes and also changes in the orientation of the wakesurf board to the wake. We doubt we can achieve all of that fully, but perhaps we can address some of the attributes needed.

We want to talk about the general concept for this build. First, we aren’t going to do things like a good craftsman would. It’ll be sort of a quick and dirty test bed to see sort of what the minimum threshold is. We don’t really know yet, but we’ll have a much better idea after the first test. We have a premise that we like to build to the least strength needed, because it’s always easy to add another layer of reinforcement, but knowing where the breaking point is, is sometimes hard to know.

So with that in mind, our plan is to use a section of cheap crappy EPS foam, roughly shape it and then add a bottom, a top and a BUNCH of reinforcements on the rails. After we get the test wakesurf board done, we will build the rails from the inside out so that it doesn’t look hideous, but for now, we’ll layer the reinforcements over the rails on the outside. It most likely won’t look all that pretty and it’ll have some drag induced from the layer and layers of carbon on the rails, but hopefully we’ll have enough strength and stiffness to base some decisions on.

Once the structure is complete, we’ll melt it. Not the whole wakesurf board, but the internal foam. We’ll drill a huge whole, most likely on the deck side, so that we can scoop out some of the foam and then pour a solvent into the hole, such that it dissolves the interior cheap, crappy foam. That process is called “lost foam” method of creating a hollow structure.

Interestingly enough, while the low density EPS foam has almost no structure by itself, it work very well in supporting the skins and preventing buckling. Without that, we’ll need to reinforce the deck skin considerably to avoid the buckling issue. We may find it necessary to reinforce the bottom of the deck with a spine like structure, but we want to avoid attaching the bottom and the deck, because we want the bottom to be able to morph to the sahpe of the wake as needed. So the deck side of the wakesurf board will most likley be much stiffer than the bottom.

We’re going to start with teh pictures, but once again state that this is just a test structure and isn’t intended to be a final production method and certainly isn’t what any of our production would look like. We’re going to repeat that LOTS, because we know there will be hateful untrue stuff spread and this project is JUST a test.

So first off we scavanged a piece of old insulation EPS. It’s not shaped and still has the protective covering on it.

We use an existing wakesurf board as a template, draw the outline on the foam and then using a jigsaw cut the rough shape from the foam.

We’ll start this project by building up the bottom skin. So we peel of the protective plastic and tidy up any of the imperfections on the board. This particular scrap piece had lots of dents and dings. We’re not going to bother fixing them, again, because it’s just a test panel, we’ll use better foam if we decide to keep this concept going for another build.

This next picture is of nomex honeycomb. The cell structure is just under 1/4″ and this particular piece is 1/16″ thick. If you’ve followed us for anything of time you know that the thickness of a sandwich structure is exponetially related to it’s stiffness. That is to say, doubling the thickness, quadruples the stiffness. So our plan is to use 1/16″ thick honeycomb for part of the bottom skin and then to double that and use 1/8″ honeycomb for the deck skin. So all things being equal, the deck skin will already be twice as stiff as the bottom skin. This is in keeping with the design considerations, we want to bottom to morph, but the deck to transmit the rider input to the board and not get floppy or morph itself.

Ok now this next picture will take a bit of explanation and again we can’t emphasis enough this is JUST an R&D wakesurf board to test the concept, so we don’t have any nice templates created and since we aren’t sure that it’ll work to begin with, we didn’t want to invest the time to create anything pretty!

So here’s the picture and take note that the honeycomb is cut inside the final dimensions of the outline.

You’re probably thinking why is all of this so UGLY! Ok, no we know you aren’t but we’ll hear from someone who heard from someone else that our workmanship is crappy, just look at these pictures!

Our thought is that we will want the outside edges of the bottom to have the greatest amount of dynamicism. As we looked at what we thought the optimum bottom structure would look like, considering both concave and rocker changes, it seemed that we wanted the greates amount of change to be available out along teh rails. The middle of the wakesurf board, at the depth of the concave, was probably already at the optimum depth, but when needing a change to the rocker or concave, it would be the area with the least depth. We aren’t saying we know that for a fact, just that it is our thinking at this time. Referring back to the stiffness equation, if the honeycomb fades to zero close to the rails, then that area will be exponentially LESS stiff then the area further inboard. Hence, by having the honeycomb stop short of the outline, the expectation is that the area closer to the rails will morph or flex sooner and with less effort than the area towards the middle of the board.  Now this is a best guess at this point, but we also have this sneaking suspicion that the honeycomb will sort of need a bowtie look to it, that is that the center of the board will need more “morphing” capability, but we’ll start here first!

Hopefully we’ve explained that in sufficeient detail that it doesn’t sound like jibberish. We really appreciate you taking the time to read all of ths and following along. We also hope that we’ve explained well enough the concept of the bottom of this wakesurf board, where it will be stiff enough to surf well, but will also be dynamic enough to change to the needed shape to best optimize the bottom shape in relation to the wake face, and the amount of force being applied. The end result for YOU as the rider, will be a faster board, a more manueverable board, not only rail to rail but also nose to tail. We are hoping and thinking that it may possibly be able to affect a tighter turn radius, not only on rail, but when dealing with deep troughs.

Also, we sure hope to have some coverage of the Koocanusa Wakesurf Challenge next week! Wish James good luck, it will be a strong contest again.

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