You know that the police need to have probable cause to pull you over and search your car. You know that officers need to have a search warrant to come into your home, in most cases, to conduct a search.
Many people assume that this means they have the same Constitutional rights on a boat. However, the reality is that the Coast Guard is not bound by the same laws and regulations as the police. They have the ability to stop your boat, board it, and search it, and they never need to have a warrant to do it.
The reason for this power is Title 14, Section 89 of the United States Code, which allows the coast guard to board, search, seize and carry out inspections. If necessary, they can even make arrests. As long as the boat is in U.S. water, they don't have to get a warrant to do it. You may feel like you're being violated, but these provision have actually been written into U.S. law.
Law scholars have spent a lot of time writing about this topic, with one of them calling them Coast Guard officers "supercops." Another scholar, named Megan Jaye Kight, stated that the documents giving these powers to the Coast Guard created one of the largest grants of law enforcement authority in the history of the United States.
If you're wondering how often you'll get boarded, some people who fully abide by the law estimate that frequent boaters may be boarded at least once or twice every year.
Be sure you know your rights when boating, especially if threatened with arrest by the U.S. Coast Guard. If you are arrested, you do have the right to a fair trial in Maryland.
Source: Sail Feed, "Coast Guard Boardings and Your Fourth Amendment Rights, Part 1," Clark Beek, accessed March 08, 2016