Narco-submarine

A narco-submarine (also called a drug sub or narco-sub) is a type of custom ocean-going, self-propelled, semi-submersible or fully-submersible vessel built by (or for) drug smugglers.

Newer semi-submersibles are "nearly-fully" submersible in order to reduce likelihood of detection by visual, radar, sonar, or infrared systems. Cargo capacity varies widely with vessel size, although several tons is typical. In 2015, the largest-known cargo of 7.7 tonnes (17,000 lb) was seized on a semi-submersible craft. Some contemporary narco-subs are capable of crossing the Atlantic Ocean.