I have looked through the FCC rules and regs and don't see the answer,

The question is this,,

Suppose you and your buddy each take your boats out on a north american
river and you want to do some idle chit chat such as "Hey, lets head to
the edge of the breakwall over there", or "Hit your trim button, you're
running to flat", What channel would you use???

It appears that the FCC desires no channel to be used for such a purpose.

What insight can you folks give to me??