When current flows around a bend in a river, it flows much faster and deeper on the outside of the bend. The velocity and depth on the inside of a river bend is much slower and shallower. You can use this to your advantage by sneaking on the inside and eventually moving more towards the center when you feel comfortable. It is usually a good idea to point your boat on an angle away from the outside wall. This enables you to quickly paddle away from the wall if you get too close. Some bends have reactionary waves against the wall that can be fun to ride. Take a close look at the picture on the right which is Upset Rapid on the Grand Canyon. Notice the strong wave train close to the wall.

Since river bends tend to undercut the river bank they are crashing against,
it pays to stay off the wall just in case. Here is a great example where the river
has undercut the wall. Imagine if the water were higher and the undercut were
hidden.