Mar 23

Wild wakesurf water flow idea

We are sort of like that motto from Missouri; Show-me. We’ve been lied to and lied about so much that we kind of like some emperical evidence before we form any sort of conclusion with regard to wakesurf related items or the folks involved. So much of wakesurf board shaping comes from a community and an environment that doesn’t INCLUDE a wake. It sounds stupid when you say it like that, but it’s true. Shaping and a lot of the underlying “tribal knowledge” doesn’t include wakes from a boat, only waves developed in the ocean. Not that our boards don’t work, but let’s open the hood and get a peek as to what’s under there. One of the biggest differences between wakesurfing and ocean surfing is that NO ONE is telling you crap trying to sell you an ocean wave! Lord knows there are any number of folks telling you that their boat wake is the best ever and that you need to BUY that boat for that very reason.  Wakes and waves are formed entirely differently, so most likely there are differences in the two environments.

One thing we really want to see is the direction of the wakesurf water flow. We know that also sounds so weird, but do you really know? We still hear tons of folks use the word “push” to describe their wake, so if that were the case then we’d see water flowing FORWARD, right? Pushing the surfboard. We know from simple physics that there ain’t no such thing as 110% efficency in a machine, so at the very least we’d be able to see water flow past the board towards the boat if there was push in any sense. There isn’t, so we won’t beat that dead horse. But what do you think about wakesurf water flow in trim? The rider is always moving forward, we know this because they remain equi-distant from the boat and all we have to do is look down at the speedometer and see that we’re moving at about 11 mph + or -.

So does that mean that the water up under the board is flowing out the back at that speed? What about all that spray we see it shoots out off the wake side rail and the opposite side too. Is that magically just sort of leaping off the ends of the board while the water down the middle is flowing backwards off the tail?

We don’t know either. So we decided to develop a little emperical evidence gathering. We want to look down into the water and see what’s actually going on there. The idea is to create a viewport through the middle of a wakesurf board and then attach some plastic streamers on the leading edge and also along the wake side edge of the viewport and watch and video what is happening with the streamers. We should note that there is what is called a boundary layer of water. That layer attaches itself to the wakesurf board and sort of moves along with it, or perhaps it’s best to say the board drags it along. Below that, the water is not really interacting with the wakesurf board at all, it’s still be moved around by gravity and a boat hull that just plowed past it. We think it will be quite interesting to see what happens with the wakesurf water flow under the board.  We should also note that we have a limited area that we are sampling and we need to be vey careful about generalizing that sample to all areas of water flow under the wakesurf board.

We’ll start the process by using a sacrifical wakesurf board, into which we’ll cut a hole for the view port. Here is the board we will sacrifice to increase emperical evidence and reduce stupid hype.

flow direction test 001

Once we cut through the board we have to seal it off, otherwise it just becomes a huge gaping hole for water to pour through. BUT we need to be able to see through the board to see what’s going on, so…plexiglass! We’ll glue that into recesses on both side of the board and that should give us the viewport we want.

flow direction test 002

We cut the plexiglass into two pieces, one for the top and bottom. We aren’t worried about cosmetics for this, so it’s just a rough cut to get to the approximate dimensions we want.

flow direction test 003

We traced the outline of the plexigalss piece onto the deck side of the wakesurf board and then roughly measured INSIDE that to make out cuts through the wakesurf board. The band left over at the top will be a ledge or lip that we’ll use to inset the plexiglass into and glue to. Here is the cut out piece and we used a jigsaw to make that cut.

flow direction test 004

We should at this time say, we HOPE we’ve left enough of the board intact along the rails to keep it from breaking. We aren’t confident of that. If it does survive, we will be BOMBARDING you with the relative strength of the composite sandwich design and how old school center stringered boards couldn’t stand up to this. 🙂 It’s still possiblr to break this sort of construction, but if it survives ths can you imagine the kind of abuse a borken board endured????!!!! This is crazy what we are doing, but we think it will make it ok.

After we removed the center section, we use a router and cut a lip about 1/8″ deep all around the outside of the hole. This recess is where the plexigalss will be attached. In the picture below, the plexiglass still has the protective plastic coating attached, as we do a test fit.

flow direction test 005

We do the same route and test fit on the bottom and in the picture below we are gluing up the bottom piece of plexiglass. We’ve intentionally positioned the reflection of the overhead lights so you can see it’s really clear!

flow direction test 006

We flip and do the same thing for the top. The last thing we will do is laminate some colored streamers to the bottom of the board. On the leading edge of the “window” and then along the wake side. The streamers will be free to flow with the water and that will give us a tell tale signal of what is happening with the water flow at wakesurfing speeds.

We hope to get 3 sets of pictures and maybe a single video that will detail the test. One in trim where the rider is just staying with the wake. One very slowly going forward towards the boat and then finally, turning the board sort of up and down against the wake.

Keep your fingers crossed that the board doesn’t snap as the rider gets up on the wake and also that our plates don’t fall off! 🙂  We’ll finish the thread on installing the FCS plugs next week, probably AFTER we show you some testing evidence from riding it!!!!

Thanks so much for following along, we really appreciate it.


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