United States security and intelligence officials estimate that up to 32 percent of all cocaine smuggled into the United States from Latin America is transported with the use of underwater submarines built by drug cartels. Security analysts believe that up to 120 narco subs are built by the cartels each year, costing $2 Million to build. The time to build a sub can take between 3 months to 1 year.
A single drug submarine can hold up to 12 tons of cocaine in a single trip, which equals to $4 Million worth of cocaine. It takes 4 men to work a the submarine, and the drug cartels pay the men $40,000 total for a single trip.
Source: Avi Jorisch, “Drug War at Sea: Rise of the Narco Subs,” Daily Beast, May 13, 2012.