Originally Posted by Hansam
Bear in mind that even if you're in the People's Republic of New York they still don't have the right to board and seize unless they have reasonable suspicion. Keep your nose clean and you should be ok but then I'm no expert on this so I could be VERY wrong.
You are indeed wrong. Federal, state, and local LE agencies have every authority to board your vessel to conduct a safety inspection (checking your life jackets, signaling devices, fire extinguishers/installed fire suppression systems/navigation lights/etc... If anything looks out of the ordinary during the safety inspection, you get a more thorough inspection to see if there is anything illegal going on. Every American Maritime LE Agency does this. It's the law, it's legal, and it happens.
Originally Posted by 14 USC 89
The Coast Guard may make inquiries, examinations, inspections, searches, seizures, and arrests upon the high seas and waters over which the United States has jurisdiction, for the prevention, detection, and suppression of violations of laws of the United States.
Pretty much every state with waterways has their own version of this for the waters under their control.
No one in the Coast Guard will give you a hard time about your guns. Provided that you tell the boarding team that you have weapons on-board and where they are located. Don't transport any NFA items, a lot of boarding officers I've come into contact with don't know the specific laws on transporting NFA stuff.
The odds of you being boarded are fairly low. The odds of you being boarded by the Royal Canadian Mounted Police are nearly impossible. The U.S. and Canada have agreements for the Great Lakes; we don't board each other's boats. The CG doesn't board Canadian-flagged vessels and the RCMP doesn't board U.S.-flagged vessels. The RCMP will not even look at you funny if you're just passing through. Just don't make a beeline for Canadian shore... They would get curious about that.
Passing through New York state waters could get a little tricky, but I doubt you'll have any serious problems. Most LEO's on the water tend to focus their attention on pleasure boats grouped together in a big gaggle... Typically means there's some BUI going on. Steer clear of heavily-populated marinas and beachfronts and you'll likely not even get noticed.
If you have any questions about a specific area of the Great Lakes, let me know. I've been to all of them except Superior and I can reach out to the Small Boat Stations over in the east and see what the local LE climate is like.