Video: On patrol for Colombian drug submarines

They're called narcosubs, or semi-submersibles, and they've now replaced planes and "go-fast" speed boats as the transportation vehicle of choice for Colombian drug traffickers looking to move tons of US-bound cocaine to Mexico and Central America.

Seriously, tons.

Each semi-sub is made to carry four to 10 tons of cocaine packed in water-tight bricks as it glides just below the surface of the water. Manning them is dangerous work, too. “The crew members must be desperate to climb into one of those coffins,” a lieutenant in Colombia's Coast Guard told The Monitor recently.

Forty-two semisubs have been seized since 1993 – with three nabbed in the first week of June alone.

But catching semisub operators is no easy task.

Check out this video of Monitor correspondent Sibylla Brodzinsky combing thick mangrove swamps with Colombian forces as they follow a tip to find a semi-sub used to transport drugs.

And stayed tuned for Sibylla's in-depth story on the topic coming later this week!