Where have you been launching?
I can tell you that come duck season, a camoed boat launched at Pine Point or up at the new all tide launch in Brunswick won't raise any eyebrows. You'll have plenty of competition at either one.
If you're launching into Portland Harbor . . . . . that may be a little different. And don't hunt there come the fall, as Portland has a no firearms discharge law, and I am told it is enforced even on the ocean within city limits.
I don't know what's good to hunt down your way in the early season when the ducks are still on freshwater, but you're close to an awful lot of salt marsh that holds plenty of ducks from Thanksgiving on. Get a Rachel Carson Refuge Permit if you hunt from Scarborough south, though you don't need it to hunt Scarborough Marsh, which is state owned.