"They still have the border of Mexico."
Not to mention thousands of miles of east/west coast shoreline and the thousands of miles of Canadian-US border.
This device need not necessarily sail into a large port. If the mooselims had one, they would stop at nothing to smuggle it in anywhere they could.
It doesn't have to come in in a cargo container either.
Sailboats in the 35-foot & above class routinely cross both the Atlantic and Pacific. There are a lot more of these than most people think.
I can think of numerous ways for a boat of this class to smuggle 1000-2000 pounds in the US.