Some of them don’t even have human crews. Just a long range on a small diesel, and a GPS connected to an autopilot. Steering from waypoint to waypoint, it will travel thousands of miles and finally run itself onto a beach when it arrives to be unloaded. Lots of unwatched beaches in the Bahamas.
Sounds like an interesting thing for Dan Kilmer to run across.
The existence of these semi-submersibles can present a national security hazard. Instead of cocaine it could be a nuclear weapon.