George DuBose

Hallo George, Waar in Nederland is 'sea foam' te koop?

George, Another country can't board your U.S. flagged vessel in international waters. If you're in their territorial waters you're subject to their jurisdiction and they can board you as much as their law allows. They can also obtain a statement of no objection to board you from your flag state, which often is granted if they have the equivalent of probable cause that you're smuggling or polluting or some other major violation. Once your flag state gives permission, which the U.S. does, they could board you. Finally, you need to be sure you really are U.S. flagged. You can't just trot out a literal piece of cloth with the stars and stripes on it and instantly be U.S. flagged. The country can check with your flag country and if they deny you're one of theirs you're stateless and fair game to be boarded by any country anywhere.
All that said, it sounds like you were in he territorial seas of another country and that is what gave them authorization to board you.

i would like to know who you deal with for your yanmar diesel
thanks
jon