I've found that to many boaters don't know the boat on your right has the right of way and the boat on your left should give way and give you the right of way. and then you've got the 10% of boaters that just don't care who has the right of way. they'll stay there course until your forced to make sharp turns and sometimes have to cross to close to other boats to be comfortable. even if I have the right of way and see I'm going to get to close to the other boat i'll start adjusting my course and speed to clear there boat.
I personally think every boater should have to take a boaters course to at least learn who has the right of way. but theres just nothing you can do about the 10% that just don't care.