Here is a better question

You purchased land adjoining a river and are in a tree 30 yards inland on your personal property. How would you feel if someone in a canoe or any other boat were to shoot a deer on your land then proceed to get out and make chase onto your land?

Golden rule goes a long way. This whole argument seems like people looking for a loophole to trespass. To this end I personally would not purchase land along a navigable river if the intended use were hunting and recreation.

I can say having just looked at a riverside residential property that the plat map and survey showed ownership to center of river. I was also told by a CO that if you hunt via boat flooded timber post heavy rain you are legal UNTIL you step one foot out of the boat and onto the ground. At that point you are a trespasser.

Just because something is potentially legal does not make it right. In this case it's not legal anyway.