They’re small, slow, semi-submersible with crews of 2 to 4 people transporting drugs—mainly cocaine—into the United States. They’re drug submarines.

Author, Dr. Bob Spalding is one of this country’s leading civilian authorities on Drug Subs. His latest book titled, Drug Subs: The Worldwide Invasion by the Narco-Submarine Fleet, explains this growing epidemic in drug distribution.

The typical drug sub is a semi-submersible vessel built of fiberglass on a frame. It is diesel powered and cruises at a speed of up to six miles-per-hour at a depth of zero to 100 feet below the surface—making them a threat to other ships in the shipping lane that cannot detect these drug subs. Each sub takes up to 6 months to build—mainly because it takes time to transport the building materials into the jungles where these vessels are built—at a cost of up to $1million. They are operated by crews of 2-4 men. Originally the crews were peasants shanghaied from South American villages. Lately, however, drug lords are turning to seasoned fishermen to crew the subs. Each crew member earns between $5,000-$20,000 per trip. Each voyage can transport as much as $250 million in illegal drugs.

What makes this trend even more disturbing is that drug lords are getting the plans for drug subs from rogue nation-states like North Korea and Russia. The next phase in the development of drug subs is to make subs with true ballast systems allowing them to operate below the surface, undetectable by sonar or our SOSUS net.

Hear the entire interview below: