" If you operate the boat in NYS, you must register the boat with the DMV. "
Not quite that simple, Cam.
From the NYS DMV web site:
NYS DMV - Frequently Asked Questions
Does my boat require a registration?
The law requires you to register any boat that is motor-driven and is operated on public waterways in NYS. The boat requires a registration even if the motor is not the primary source of propulsion. If you operate the boat in NYS, you must register the boat with the DMV. ...
What if my boat is documented by the US Coast Guard?
You must register the boat in NYS if:
the boat is not used for commercial purposes in NYS, and
the boat will be used on public waterways in NYS for 90 or more consecutive days. ..."
The average water cop or tax inspector at the docks may not be aware of that, or may not care. If a state tax inspector stops down to City Island (as they do) and takes lists of seasonal tenants (as they do) and see a seasonal rental with a NJ registration on the boat--he'll cite it for tax evasion and let the owner come to tax court to show proof that it doesn't apply, and the boat shouldn't be arrested. So if anyone is planning to use the USCG documentation with 89-day hops...make Real Damn Sure you get receipts and have a log proving you were out of state. The tax men here have heard it all before.
Now, if you get rid of the engine and have a true sail
boat, rather than the "auxiliary sailboat" that most of us sail on...that's a whole other story. [g]