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Mar 14

Wakesurf board flex

We went back and looked at the video by Jason Lybeck from Faction Boardshop yesterday and sort of took notes. We really like the ability to play the videos back in slow motion. The GoPro 3 has this one mode that takes 240 frames per second, which is ridiculously fast, but of course the quality of the individual pictures isn’t great. BUT as a tool in watching James Walker ride and load up his board for partricular tricks, it’s invaluable. We’ll need to get one for just that purpose!

That got us thinking about wakes and boards and how they interact. Remember that massive G25 from the Sacramento Boat Show. That is a beast of a boat and probably the single most innefficient wakesurf boat ever. Bare with us here for a minute. The lifting forces of a wakesurf board aren’t developed by the weight or ballast by itself. We need that ballast or weight to stuff the back of the boat into the water, but it’s not the key factor in wakesurf wake development. In fact it’s probably an indication of the efficiency of the hull for wakesurfing. The more it needs, the less efficient that hull is for wakesurfing.

Not that it can’t be done, just that as a design element, the more weight a hull requires, the less likely that it’s really designed for wakesurfing. Or at least there wasn’t much thought given to how much weight it required. So that massive G25, is going to take massive amounts of weight to cause it to list. OR the NSS dealio has to develop a nice clean crisp wake for wakesurfing. The jury is still out on that one, but big huge boats typically require big huge amounts of ballast.

What causes that huge rush of lifting forces in our wakesurf wakes is the depth of the hull into the water. So technically, it’s possible to develop a hull that can develop such a wake without the addition of ballast. It most likley wouldn’t be a real user friendly boat, but it’s possible that someone could design such an animal. We also know that the longer the contact area of the boat in the water, the longer the wake will be. That sort of equates to a more weight forward arrangement. Also that more weight towards the rear creates a shorter/steeper/taller formed wake. BUT that’s all becase of the shape of the hulls and how we stuff them underwater so that when we plow forward it creates the shape that we want.

We’re not absolutely certain of this, but we think all boats that are used for wakesurfinng, now, are really acting as displacement hulls at wakesurfing speeds. So, change the shape of the hull so that it mimics what we do with ballast, only don’t require the ballast and you have a hull enginnered for wakesurfing and that is the single most efficient hull for that purpose.

It’d probably sell 1 unit a year and be miserable for all things but wakesurfing, but conceptually, it’s just creating a running surface underwater that mimics what we do with ballast.

Ok, so ballast isn’t the factor. We’d guess there are folks that sort of wear that as a badge of honor…my reverse hippo-clone take 6,000 pounds of ballast, booyah! What that translates into is, my hippo-clone is really poor at sinking the appropriate depth for wakesurfing. So, now some boats take 6,000 pounds of ballast and some take only 2,000 pounds. That’s a 3 to 1 ratio. Are the wakes 3 times as tall? Where one is 2 feet and the other is 6 feet? That’d be so cool, but no. That really makes the efficiency issue clear doesn’t it? If there isn’t a direct correlation between size, length, or height, the boat that requires the most weight, for the same basic wake, is the least efficient. Could be it’s a better wake, because that’s purely subjective, but it’s less efficient.

Lifting forces, the power that we experience comes from the water seeking it’s own level and how much water is displacedwithin the narrow band that we wakesurf. A 200 inch beam boat, that is forced under water with tons of ballast, is probably going to have a LOT of force on the opposite side of the centerline that is just wasted in terms of wakesurfing it. Right? If you have 1 ton of ballast in the opposite corner and the wake is all frothy, that ballast is certainly wasted in terms of developing an efficient wakesurf wake on the side you’re currently riding.

The ballast number itself isn’t what makes the wake. In fact as large as some of those numbers are, we’re pretty sure that manufacturers are ignoring them as they have to be dangerous or illegal. Between two boats, more ballast does not equate to more lifting forces. It certainly can, but a more efficient hull with less total ballast, will develop the same lifting forces as an ineffcicent hull requiring more ballast.

From that we know we are always managing the lifting forces based upon the overall height of the wake, forward. If a wake is 6 feet tall, there are significantly more and faster forces pushing that water up against gravity and rushing from the depth of the PLOWED or displaced area up and above the equilibrium area water wants to see.

Currently there is very little difference in wakesurf wake heights. A few inches here and there, but there isn’t a situation where one wakesurf boat is developing double overhead height wakes and another is at 2 feet. They are all pretty much…can you guess it? They are within the range of the freeboard of the boat, when listed, or sunk. The deeper that goes, the taller the wake will be and the more lifting forces it will have.

As we look at the development or design of wakesurf boards then, almost all wakes are principally the same. Now we know that is like spitting in your face, but we aren’t saying your boat sucks. There are myriad reasons you love your boat, just that for the most part it’s wakesurf wake is really very similar to all other wakesurf wakes. We’d guess if you could create objective measuring criteria like height/fixed length at speed/lifting forces that all wakesurf boats currently are within +/- 10% of each other.

…and that boys and girls is why virtually all of our wakesurf baords are starting to look the same. :)

As we thought about that, about how virtaually all wakes are the same, things like wakesurf board flex become tuned to the rider. His/her weight, height and probably muscular development. So a light weight youngster needs a board that has more flex than a rider that is 200 pounds with lots of leg muscle.  Wakesurf board flex is really a function of the rider and not of the wake.

We’ll say it again, what doesn’t come into play, is the power of the wave itself…because it almost is irrelevant in the design criteria. It’ll be almost the same from G25 to whatever the lightest weight 20 foot V-drive boat is. The lifting power of the wave, the amount of ballast is almost a non-factor.

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All decent wakesurf boats develop the same basic lifting forces, have the same basic height and length. The only thing that seems to be of significant variation is shape of the wake.  Within a relative range, we’re guessing it’s probably +/- 10% as it relates to ballast.  Certainly nowhere near 200%.  So, as a function of ballast, there is no single boat that is developing twice as much height/power than any other decent wakesurf boat.  Sure the G25 compared to an aluminum Jon boat, but not compared to VLX or V226 or whatever.

So we’ll leave you with a question, is the board you are riding, optimized for the level of flex you require based upon your weight and muscle definition? For the board you ride, are there design elements that are different for a 200 pound athlete and for a 90 sixth grader? If you think there are, what are they?  We get length, but do you really think that is the only thing that should change?  L:ength is about the only thing that most manufacturers, pro shop employess and the online cheerleaders note or recommend.  What do you think? 

Thanks so much for following along as we ask the tough questions and we’ll talk about some of those design elements that you saw in the video of James Walker landing that back big. :)

 

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