As I have looked around I don't see articles on tubing on rivers. Given the normal direction of kicking, I.e., backward, one would face down stream and ferry to get to where you want to go. The trick to getting places in a river is to paddle to places where the watter is going where you want to go instead of paddling to where you wnt to go. A great method of doing this is the upstream ferry. This involves paddling upstream at an angle to the current toward the piece of water that is going where you want to go. Look at where you want to go and something in the back ground. If the background is moving upstream turn more into the current; if the background is moving down stream turn more toward the bank. This assumes starting from the middle toward one side or the other. Do this on Class One (curent w/ turns) water before you try it on anything else. With fishing gear I'm thinking Class Two (small things that can easilly be missed and very small waves) water would be the limit for most folk, althoug,h the canoe liveries rent tubes, canoes and kayaks to all comers up to Class Three watter. There are two things that are dangerous on moving water; trees that have fallen into the water and low water dams. I would rather be in a barbed wire fense that a tree; the fense will cut, the tree will drown. A low water dam usually creates a hydraulic which is water droping straight down creating a surface current going upstream. The only way out of this is to get as deep as you can for as long as your life jacket will let you. If you try to swim out on the surface the current will keep pushing you back into the downward flowing watter. Do not assume you can tell the nature of a drop; I have looked at drops that looked a couple of feet from above that were 15 feet w rocks. The other safety measure is to be going towards a way out of river when going around a blind corner. This is true even if you ran the river yesterday cause trees by rivers fall. Having given the obligatory safety and manuvering talk about the only way to dronw on a well used Class I river is to get drunk and not wear a life jacket. Just an aside. I used to be a guide on Brown's Canyon in Colorado; this is Class Four watter; there were lots of pools of still water and no fisherman?