The U.S. Coast Guard has captured a homemade submarine loaded with 3-1/2 tons of cocaine off the coast of Costa Rica, Reuters reported Nov. 20.

The vessel, crewed by three Colombians, was believed to be heading for the United States. The low-tech, 45-foot submarine could only go a few feet underwater, officials said, and was found near Coco Island, a remote spot off the Central American coast.

There have been past reported of drug smugglers using submarines to deliver narcotics to the U.S., including a supposed plan by cocaine cartels to buy a surplus Russian submarine.