![narco submarine](https://static-ssl.businessinsider.com/image/55b0d820371d22ce178b8b83-894-508/narco sub.jpg)
US Customs and Border Patrol/Amanda Macias/Business Insider
US authorities gained control of a "narco submarine" filled with 8 tons of cocaine.
On July 18, a Coast Guard $4 a self-propelled, semi-submersible vessel carrying 274 bales of cocaine weighing more than eight tons, according to a press release from US Customs and Border Patrol.
The four individuals found with the illicit contraband were detained by US authorities.
Similar to a submarine, "narco-subs" are custom-built vessels used by traffickers to move large amounts of drugs. The first narco sub was $4 in 1993 and was built from wood and fiberglass, could not submerge, and could only travel at 10 miles per hour.
US Customs and Border Patrol US authorities sit on a "narco submarine" found off the coast of El Salvador.