Following the discovery in February of Colombia’s first fully submersible “narco-submarine,” built by drug cartels to ship cocaine through the Pacific to the United States via Central America and Mexico, the Colombian newspaper El Pais has produced a special report on the evolution of submersible and semi-submersible drug-trafficking vessels, whose increased use demonstrates not only the creativity of drug gangs in finding a way to get their products to market, but the extent of their resources in being able to privately construct such sophisticated devices.

The emergence of the semi-submersible followed work by U.S. and Colombian authorities to increase maritime interdiction in the Pacific in the 1990s and 2000s, with sea patrols and radar tracking managing to intercept many of the speedboats or so-called “go-fasts” the traffickers used.

The traffickers had to come up with a new method: traveling below the surface of the water. Initially, as Colombian Rear Admiral Hernando Wills explains in an interview in the video attached below, the boats were semi-submersibles that were crudely designed like go-fast boats with another hull placed on top to allow them to travel just beneath the water’s surface.

Wills describes the first discovery of one of these crafts, which took place in 1993 on the Colombian island of Providencia. The craft was “very rudimentary,” the navy officer says, with the capacity to carry just one ton of cocaine.

Later versions sunk slightly deeper and were often constructed from fiberglass in order to make them hard to detect by radar. And the vessels would have a system of drainage valves to make them easy to scuttle if intercepted, sending the evidence to the bottom of the sea.

The latest seizures, however, illustrate a rapid evolution in capabilities. In contrast to these early attempts, the submarine found in the southwest province of Cauca in February is 30 meters long and three meters wide, and can carry four crew members in its air-conditioned interior, which even features a small kitchen. Perhaps most importantly, it can carry eight tons of cocaine, dive eight meters underwater, and reach all the way to the coast of Mexico, with only a periscope remaining above the surface (see El Pais’ diagram).

This was the second such privately-constructed fully-functional submarine discovered, after the July 2010 finding of such a craft in Ecuador close to the Colombian border. That submarine could go 20 meters deep, and carry 10 tons of cocaine.

Such capacity is a game changer. A 2008 U.S. military Southern Command report predicted that semi-submersible vessels would soon be able carry 330 tons north each year or close to half of all cocaine moving north.

There is some evidence this may already be the case. A 2010 United Nations report on The Globalization of Crime said that in 2008, 46 percent of all cocaine seized by Colombia in the Pacific was found on semi-submersibles. With the U.S. estimating that 69 percent of cocaine entering the country in 2007 left Colombia via the Pacific, semi-submersibles have in the last few years been responsible for a very sizeable proportion of the global cocaine trade.

However, the subs represent something that goes beyond their capability to carry drugs. They are home-made, privately built by drug traffickers in makeshift jungle workshops. The amount of funds needed to set about such a project is huge, with navy personnel estimating that the Cauca submarine likely cost more than two million dollars to build. This ability to invest and take on long-term, high-value projects is a warning of the traffickers’ high level of resources and organization.

The increased use of submersibles and semi-submersibles is highlighted in the UN’s International Narcotics Control Board’s latest annual report, which says that the use of semi-submersibles for drug trafficking has “strongly increased” in recent years, quoting Colombian government figures that while 19 such vessels were seized worldwide between 1993 and 2007, 34 were seized in 2008 and 2009 alone.

Colombia’s territory bordering the Pacific provides the ideal environment to construct and hide a submarine, as much of it is wild and remote country criss-crossed with rivers and jungles. Much of the region is under the influence of drug trafficking organizations such as the Rastrojos, with a heavy presence of the Revolutionary Armed Forces of Colombia (Fuerzas Armadas Revolucionarias de Colombia – FARC), particularly the rebels’ 29th Front in Nariño and 30th Front in Choco.