katy wrote:

For example, all of Maine down to Cape Small is Intl, and that
includes the Kennebec all the way up to Bath. Harbors such as Block
Island ans Edgartown are Intl, and so on. Admittedly, most of the
navigable channels south from there are Inland, but there are still
plenty of Intl channels, such as all of Alaska.

Now whether a CG boat would actually try to give a ticket to a tall
ship, that's a different question.

So does that mean the US can't keep ships under dither flags out of
those areas because they are International?
That line, called the "Colregs Line," merely shows the area where the
International Rules are replaced by the Inland Rules. It has nothing
to do with territorial waters and economic zones and all that stuff.