I am Bill Dvorak of Dvorak Expedition based out of Nathrop, Colorado here and we are going to talk a little bit about some basic kayak instruction. And it does not matter if you are kayaking or rafting or any other kind of craft you want to take down the river, a canoe, buggy boards, anything.
The basic skill is knowing how to read the water and so you have to understand hydrology.
What they are doing now is just kind of maneuvering down the river. Where Tee went over, there is actually a rock and a small hole created, and one of the key things that you really need to understand if you want to become a kayaker is how to read water. And right now in this raft we are actually going down the tongue or the “V”, and there is only two things that create waves. That one is water colliding with itself or has pressure from one side to the other and the other is where it goes over an obstacle, typically a rock.
So if you look down the stream, down on the right there about 50 yards, you will see some white water, that would be caused by an obstacle. So there is a rock in the water there whereas the waves that we are on, a nice pressure waves which would indicate the deepest channel of the river. And that is typically where if we are just running down the river, we want to go where the deepest channel is, so it is the fastest and it is the easiest. And the things we want to avoid is like downstream on the right there where we have that tree sticking out into the water. We call those strainers. If that was across the current, it would just collect a lot more debris like we have here on the left.
And so we are always looking for either the main tongue or a secondary tongue. So right now, Tee is kind of over in the main tongue, he is always on the secondary tongue and there is kind of some rocks here in the middle. We are looking for what we call the V tongue or the channel and that is where water is being pushed into the deepest part of the river in the line of least resistance. And then we are looking for waves and there is only two things that create waves. As that V channel comes together, water collides with itself, and water is not compressible so the only place you can go is up. So we get a line of what we call pressure waves or tail waves.
We are looking for those pressure waves and tail waves normally to run because that is the deepest channel, the fastest water that is going to be the easiest place for us to go ahead and run our boats.
The other that you can get however is you can get the water running into an obstacle, typically a rock and it cannot penetrate the rock so it has to go around the sides and then up and over it and that will also create a wave. So there is only two things that create waves, pressure and obstacles. And you have to learn to identify which one is which and usually you are trying to avoid the obstacle wave unless you are actually trying to eddy out behind that or do some sort of a move and use that wave to your benefit.
And then the next thing you need to understand is that typically on the sides of the river, the water will come down and get deflected. And as it gets deflected on the back side of that deflection, there is a partial vacuum and water will run back upstream into that partial vacuum and we call that an eddy. And right here at that point of diversion, we have an eddy fence which is where the water is confused. It does not know whether to go on downstream into the main current or actually circulate back into the eddy that is going back upstream. And the further away from the obstacle you get, the broader that eddy fence becomes.
So typically in kayaking, what we are trying to do is we are trying to cut into the eddy as close to the point of diversion as we can, as long as there is enough room for the nose of our boat to swing in there, because as soon as the nose of our boat penetrates that eddy fence, the upstream water is going to kick the nose one way while the downstream water is kicking the stern the other way and you just do a natural kind of gradual turn into the eddy fence. And as you do that transition, typically in kayaking you are always leaning downstream but as you do that transition you have to change your lean because downstream in the current is this way and downstream in the eddy is the other way. So, you have to sort of change your lean as you make that transition and lean into the turn. It is a very akin to leaning a bicycle into the turn. You are always leaning into the turn. If you do that, then you cannot go wrong because that upstream water would not catch you upstream rail and turn you upside down.
The other thing that is going on is on the side of the river, on the side of those U-shape, that U-shaped channel, you will get helical flows which is kind of like stretching out a slinky. And that water is coming up to the edge of the U-shape, coming out, hitting those laminar flows and going deep and sort of V’s down the river.
When you get water compressed that begin at the side of the wall or something, it actually pushes those helical flows up in the air and so you get a difference in actual elevations of the river sometime.
So, you have got to understand that is what is going on when water gets compressed against the side. So when that water runs into those rocks down there, it creates compression on those helical flows and builds up what we call a big pillow and you can just use that pillow to just stay right off the wall. You just got to realize it is there and face away from it and then the cushion will just take you right around. It is called white water because all this white is aerated water and it is about 40% to 60% air. And all this is being caused by water running over rocks.
And that is the basis of reading the water. It is just understanding there are only two kinds of waves, knowing what creates an eddy and what an eddy looks like. And then the last component of that is sometimes if the obstacle wave is big enough and the water going over the top of the obstacle wave is high enough, there will actually be a partial vacuum created on the downstream side of that rock wave or obstacle wave and that water will actually work back upstream as well to fill that partial vacuum. And we call that a hole or hydraulic. And you will actually see out in the middle of the river, the wave actually moving back upstream. So, you know that there is a partial vacuum on the back side of that obstacle wave.
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