If you boat and fish long enough, at some point you’ll run into an emergency situation on the river. Most of the time you can’t hear very well due to thousands of cubic feet of water rushing by and many times you’ll be separated by large distances or dangerous obstacles. That’s why knowing at least the very basics of pointing positive, knowing river right vs. river left and a minimum of hand signals is very important.
While the gentleman in the video below is from Bulgaria, his tutorial on signals and communication can be used anywhere in the world if you’re on a river.