Title 12 S11212
It only says you are banned on a motor vehicle. It says nothing about any ban on boats. Section 1A says you cannot shoot from the boat though. So yes carry, no shoot.B. A person may not, while in or on a motor vehicle or in or on a trailer or other type of vehicle being hauled by a motor vehicle, have a cocked and armed crossbow or a firearm with a cartridge or shell in the chamber or in an attached magazine, clip or cylinder or a muzzle-loading firearm charged with powder, lead and a primed ignition device or mechanism, except that a person who has a valid Maine permit to carry a concealed weapon may have in or on a motor vehicle or trailer a loaded pistol or revolver covered by that permit.