wow, this is more serious than my initial curt reply

1) navigating a waterway is typically measured by a canoe..

2) though you may legally be afforded "public access" to private property, that doesn't automatically grant you a right to reap it's resources while there, therein lies the the rub

3) lake people are usually pretty easy going, obviously he is threatened by the fact you own a Firebird.

so I recommend to try a bit of kindness and submission first, apologize you meant no harm, tell him you understand his position (don't say he is right until you know for sure and surrender that too if true and it's over), tell him what a beautiful property he has and how you would be proud to own it, talk about him and what he has done....

he is proud of his digs and wants to share it with friends, not fight with enemies, I bet you will find out both of you are good people and just have a difference of opinion that can be easily ironed out if you are willing to try.

and if that doesn't work, send lawyers, guns and money, maybe even hire a hit man to off that sob?