I don't think he actually expects to get very far in any of his tries. The attention from his eventual arrest and following news articles are his actual goals. Kinda like that flat earth rocket guy. And they'll both probably end the same way, dead by hubris.

Probably for operating an unregistered watercraft or not having a transponder. The kind of things maritime law requires for stuff like not getting shot be some idiot, not being IDed as a naval mine by the Navy, search & rescue, not hitting other ships, customs and border enforcement, etc, compelling border compliance, etc. There's a surprising amount of rules for doing stuff in the ocean.

Edit: apparently the vessel isn't technically seaworthy, there was a hurricane evacuation notice in the area, and he also threatened to kill himself and claimed to have a bomb. All of these things are usually guaranteed to piss off the government to varying degrees.