First off Congratulations to our latest Flyboy Wakesurf Huge First Annual Surf Style giveaway contest Mr. Brandon Vincet was one of several folks to correctly anser the question and has won the Inland Surfer wakesurf rope. We have one last lead in prize before the GRAND PRIZE so be sure to read every day over the next two weeks, we are about to give away the Inland Surfer Flyboy Division James Walker signature model board a retail value of almost $900! Who else is giving away almost a grand in a single prize just for answering a question?! No one else!
If you don’t win, be sure to check with the good folks at Towanza.com for the best price on the best wakesurf boards!
We are in the process of working on two wakesurf board projects one is for fun and isn’t really associated with R&D but more just to see if we can do it and at the same time, maybe delve into the physics of wakesurfing. The other is a return to our old days of wooden skinned wakesurf boards. In the past we’ve used Balsa and that was certainly fun and created a lively board, but left too much flex for a contest level board, in our opinion. About a year ago we purchsed a supply of Basswood after reading some of the construction techniques employed by Josh Dowling. Josh is located in Australia and utilizes Paulowina wood as his skin a rails. His rails are unique in that they are a layering of divinycell and paulowina. The Paulowina is significantly more dense than Balsa and so required less of it on the rails to get a good flex pattern compared to balsa alone.
Here is a picture of two of the Basswood pieces that we dug out.
The other project, if we can call it that, is a empty plastic bottle wakesurf board without using any resin or glue, just the empty bottle and plastic wrap. It’s not a recycling project, instead we just wanted to see if we could actually wrap a bunch of empty bottles together to make a wakesurf board. However, you know we can’t leave an opportunity to explore some surf style physics, when given the chance!
Now the empty water bottles are filled with air when the water is drained from them. We have two different substances, water of course we know is a liquid and air is a gas. We also know that water is much denser than air, which is why there is no air at the bottom of the lake, just water. One cubic foot of water weighs a LOT more than one cubic foot of air. Part of the reason that is true is that the molecules of water are much closer together than are the molecules of air.
Have you ever observed the air in your car tire? Is there a flat spot at the bottom even when the tire is properly inflated? Yes indeedy! The air in your tire is compressible, the molecules are spaced farther apart and so when pressure is applied they are compressed together. If air wasn’t compressible when you hit small bumps or the like the there would be incredible amounts of jarring passed on to the suspension system which would most likely be too stiff to manage them. The ability of air to be compressed some, actually acts as a dampener to your suspension system. Also, most of you have probably filled your propane tank from a camper ot BBQ and the propane, which is a gas, is compressed such that it fits inside the small tank you take to your gas station.
What about water and most other liquids? The molecules of water and most liquids are already pretty closely packed. Water can be compressed a slight amount, but the pressure has to be extremely high and the compression is very minimal, for most everyday purposes it’s considered incompressible. We can observe this when wakesurfing as our boats plow through the water. If the water was compressible would we have wakes? Probably not, the water would just get pushed into a smaller volume, maybe like a nerf ball that we scrunch up. Then as the boat moved passed and released the pressure the water would just epand back to it’s normal shape. If there was a great deal of elsticity it might bounce back and that would be cool, but water doesn’t have that attribute. It’s probably more like sand, drag a spoon through sand, it pushes out of the way, doesn’t compress and then when the spoon is gone the sand slides back down into the trough, mostly.
Water we know is a liquid and will seek equilibrium in terms of height, so any of the water we push away with the boat, will flow back down to fill the void. So we drag our boat through the water and whats happen to the water that we’ve pushed out of the way? Some goes to the sides, a BUNCH goes up forming the wake, but none of it is compressed, well maybe a little but not very much. When not constrained, and a pressure is applied water doesn’t compress it displaces, then when the pressure is removed the water seeks equilibrium and returns to that same height. What direction do you think the water is flowing as it’s pushed away by the boat passing through it? It’s up on the start of the wake, isn’t it? Out and away on the sides.
Now admit it, physics is uber cool!
So what will happen to the air in our water bottle wakesurf board? It’s going to compress down to a fraction of it’s original volume. What happens to the plastic bottles themselves? They’ll squish! The good thing is that the air will not completely compress to the point of being a vacuum, instead just somewhat. The somewhat is pretty significant though, so in our examples the empty plastic bottles get pretty squished, BUT don’t pop, epxlode or crack! So for our empty water bottle wakesurf board we can use them!
This is a picture of some empty bottles we wrapped together for a test panel, you can see them sort of tucked in to the neck of the center bottle. Also, the bottles are filled with air.
Here is the result of a 200 pounder standing on the test panel. Rather squished, but not burst open. So the air inside compresses, but not so much as to cause the external container to fail.
There you go! We’ve got a serious project and a fun one in the works, we hope you’ll come back and follow along!