Wakesurf board optimum bottom shape

We’ll apologize in advance for the hurried and rather amateurish drawings, but we want to get this post into the thread before we announce something NEW tomorrow! Remember in the last post we talked about wakesurfing the carbon fiber hollow wakesurf board? That board used honeycomb for the skins (so there you naysayers!) and the core was melted away using Xylene and Acetone. What we mentioned in that post was the concept of a dynamic bottom. ALL wakesurf boards currently on the market have static bottoms. Some minor flex stuff, but the bottom itself is always static. This experiemnet, the carbon fiber hollow wakesurf board with honeycomb (HA! you naysayers ) has a bottom that will sort of morph into the shape of the wake, creating a bottom shape that is always optimized to the water flow, within the relative range of the constraints imposed by the physical shape of the wakesurf board.

Let’s look at one of the issues with a static bottom. It would be easy for a shaper to assess what the best bottom shape would be for a particular situation or wake or rider and then sort of carve that in stone by shaping the foam and glassing over it. But what happens when the wakesurf board is in a different environment? That optimization is lost, isn’t it? We aren’t really sure how much optimization is lost, but we can all say that once the board is turned or the angle of attack differs from that one spot where the bottom shape is optimized, the optimization is lost. ALSO, what about when the board is revert? Obviously the bottom shape that was optimized for going forward wouldn’t be optimized for going backwards.

So here is a really crude drawing that we hope will represent the componets of the wakesurf board wake interface.

The blue arrows represent the water flow UP the wake face – that’s the lift and NOT push we’ve been talking about. I know it’s hard to break that habit, especially with folks pimping boats…err, promoting boats, but the reality is the water flow is UP creating lift, not pushing you down the line. The black line on top is the orientation of the wakesurf board down the face of the wake and the red line is an assumed theoretical optimization of the bottom shape of the wakesurf board.

From a static point of view, of we KNOW that shape is optimum, that’s ridiculously easy to shape that isn’t it? Absolutely! Code it in your shaping program and viola, every board you crank out has that optimum bottom shape. Or does it? What of the angle of attack changes? Does that optimum bottom shape remain in that exact same position? No, it doesn’t because every change in orientation also changes the orientation of the bottom shape because it’s static and as the board tilts either up or down or side-to-side, that bottom shape changes in relation to the board and not to the wake. Imagine for a moment your cars suspension. You’re going into a turn and lets say there are some weird portions of the turn that slant from the inside of the turn down towards the middle od the road, sort of like an off-camber turn. Would you want the suspension of your car to remain constant through that funny angle? Forcing your car to lean away from the turn? That wouldn’t be optimum, would it?

We’d want the suspension to absorb that extra force on the inside and allow the wheel to raise up, so that ALL of the tires remained on the ground and the reduced body lean or roll would possibly allow the car to travel faster through the turn. Now water isn’t a road, it moves all around and sloshes, but still it offers resistance and we have to remember when that we plow over 2 tons of boat and ballast, some folks plow 4 tons! That is going to displace a LOT of water and that water is going to come rushing back UP and try to resume it’s natural state. That flow is pretty powerful and so it can provide enough force to shape the bottom of our hollow wakesurf board. Some boats are very innefficient at wake formation. If it requires 4 tons of water displacement and it’s not twice as powerful, or twice as high as most boats, then the shape of the hull just isn’t optimum for developing a wakesurf wake.

Other boats create monsterously steep wakes that are super tall with that much weight and the water in both of those instances creates a significant amount of force and that force is enough to dynamically shape the bottom of a wakesurf board. Would the optimum shape be the same, for the ridiculously weighted boat with marginal height increase or the OTHER ridiculously weighted boat with a super steep and tall wake? They wouldn’t be the same, because the forces being created on the wake face are different and we know that capturing the forces from the TALLER wake would be much easier than on the less tall wake.

Also, lets look at something more simple, what if you just changed the angle of your fall line down the wake? Would you want the bottom shape to remain exactly the same as it was in the first picture and orientation, above? Well that’s a trick question, isn’t it? We do, but we want the bottom shape to change in relation to the presentation to the wake face and not the angle of the wake surf board. That requires that the bottom shape be independent of the deck surface.

Something like this:

C’mon you know that is the coolest concept you’ve ever seen! Now if we can just harness it to make it effective for wakesurfing. So far, it’s not quite ready for prime time as the reaction time of the bottom felt slow, but also, we want it to LOAD up so that when you released the board from the pressure of the water flow, the bottom shape SNAPPED back into place. In this prototype, that ain’t happening!

Thanks so much for following along, we really appreciate you taking the time out of your day and we hope to have more to share with you on these concepts soon.

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