In 2006, the first homemade drug-trafficking submersible to be seen at sea by American law enforcement officers was interdicted 100 miles off the Pacific shore of Costa Rica, carrying 3 tons of cocaine. Ever since, these stealth vehicles, sometimes called “narco subs,” but more properly known as self-propelled semi-submersibles (SPSSs), have been intercepted periodically throughout the vast eastern Pacific expanse of the “transit zone” – the 42-million-square-mile area comprising the drug trade’s maritime approaches to the United States from Central and South America that also includes the waters of the Caribbean Sea and Gulf of Mexico.
The SPSS is a sophisticated tool for drug smugglers, but as far as submarines go, it’s actually fairly crude. None of the vessels captured at sea so far is capable of submerging fully; their crews (usually about four or five people) must have access to outside air. Typically about 30 to 100 feet in length, some can carry more than a dozen tons of cocaine.