It began with better radar: Until the 1990s, the preferred method for drug smugglers in the Transit Zone – a 42-million-square-mile area comprising the maritime approaches to the United States from Central and South America – was the “go-fast” boat, a small, often multi-engine speedboat that could outrun Coast Guard or Navy vessels.

As radar technology improved and the Coast Guard was given additional capabilities, more go-fast boats were intercepted, but the amount of drugs reaching the United States did not decrease – in response, traffickers seemed to be sending out more boats. There were also rumors of a new adaptation on the part of the Colombian cartels: stealthy submersibles, smuggling drugs into the United States. A couple of submersibles were discovered, one under construction in the Colombian jungle, but none could be conclusively tied to the drug trade; there was, for several years, no real evidence found to support the rumor, leading many to call the sub “Bigfoot.”

Bigfoot was indisputably sighted in November 2006, 100 miles offshore of Costa Rica: a homemade semi-submersible, made of wood and fiberglass, carrying 3 tons of cocaine. Its interception was a collaboration between the Coast Guard, the U.S. Drug Enforcement Agency (DEA), the FBI, and Colombian and Costa Rican authorities. The semi-submersible’s crew of four included two Colombians, a Guatemalan, and a Sri Lankan.

Often called “narco subs” in news coverage, the vessels are more accurately called self-propelled semi-submersibles, or SPSSs. None of the vessels captured so far – except for one, discovered in July of 2010 – is capable of submerging fully; crews must have access to outside air. From about 50 to 100 feet in length, some semi-submersibles can carry more than a dozen tons of cocaine.

Nevertheless, the SPSS has proved maddeningly difficult to intercept. It rides low, often with just a pilothouse above the waterline, making it virtually undetectable by radar. The upper hull is colored to match the ocean’s surface, making it particularly difficult to spot by air, and some SPSSs have moved their exhaust ports to their undersides, cooling the exhaust sufficiently to make it invisible to infrared sensors. The SPSS is also designed specifically to be sunk before it can be boarded by law enforcement officers, with scuttling valves that send the vessel and its cargo to the bottom of the ocean and allow the crew to float free.

At Last, Some Success

The United States’ anti-drug effort in the Eastern Pacific – where, in 2007, 68 percent of the cocaine moving through the Transit Zone was brought into the United States – involves many different U.S. agencies and international partners. A typical drug interdiction begins with actionable intelligence on a suspected trafficking vessel, which is then monitored by a combination of agencies that may include U.S. Customs and Border Protection (CBP), the DEA, the Coast Guard, the Navy, and the appropriate international partners. Good diplomatic relations and bilateral cooperation with nations in the region are important, according to Capt. Kevin O’Day, chief of response for the Coast Guard’s 11th District, headquartered in Alameda, Calif.: “We have operational procedures in place with Ecuador and Colombia, and we have bilateral agreements with many countries. Panama is a really important partner, because of its logistic location and the fact that a lot of these vessels from Colombia stay along the shoreline and they cut into Panamanian waters. That relationship, I would say, is one of our most significant, just because of where the drugs are falling right now,” O’Day said.

The 11th District takes the lead for counter-drug operations in the Eastern Pacific, where Coast Guard cutters and Navy frigates serve as platforms for the Coast Guard Law Enforcement Detachments (LEDETs) that perform the interdictions. “[The Coast Guard is] kind of the tactical commander for the ships when they are on a case,” O’Day said, “directing their actions through intercept, and then we’re in charge of the post-seizure logistics and case package preparation.”

Once Bigfoot had been proven real, solving the tactical puzzle – how to intercept and board an SPSS without being detected – proved difficult. For two years, the Coast Guard and its partners were frustrated, as interdicted SPSS crews scuttled vessels and cargo, eliminating any evidence that could convict them of trafficking. Time after time, a drug interdiction instantly became a search and rescue case, as the Coast Guard plucked the smugglers from the water and returned them to their country of origin without being able to charge them.

The operation of the SPSS in the maritime approaches to the United States was perceived by many to be a grave threat, and not just because of its ability to haul cocaine. “If you can move that much cocaine,” posited Navy Adm. James Stavridis, commander of the U.S. Southern Command from October to June of 2009, “what else can you put in that submersible? Can you put a weapon of mass destruction in it?”

In September 2008, the Coast Guard turned the tide with two stealth seizures of SPSSs, their crews, and cargos. Each semi-submersible was found to be carrying about 7 tons of cocaine. At last, the threat posed by the SPSS had become more than just a rumor. Armed with this evidence, the U.S. Congress acted quickly; within a month of these seizures, the Drug Trafficking Vessel Interdiction Act, which makes it illegal for an SPSS to operate covertly in international waters – for any reason – was law. “Those two cases, and some of the video footage we got from those two cases, were the straw that broke the camel’s back in terms of pushing that legislation through,” said O’Day. “It showed how dangerous the operation was – trying to board a vessel at night covertly, with water splashing over the boarding team’s boots and legs, just to get a bale of contraband, because before the legislation was passed, we had to get a bale in order to prosecute the drug runners.”

The Colombian government promptly followed suit with a law that punished the construction of an SPSS with up to 12 years in prison, and the transport of drugs in them with up to 14 years.

Raising the Stakes

After passage of the U.S. law, the Coast Guard and its partners got down to work. SPSSs were interdicted on three different occasions between Dec. 31, 2008, and Jan. 9, 2009, off the coasts of Ecuador and Colombia. All three were sunk before they could be boarded, but their crew members – a dozen in all – were brought to the United States for trial under the new law.

The Coast Guard faces a new challenge in preparing the cases under the new law, which some critics question as unconstitutional because it asserts U.S. legal authority over activities that occur in international waters. But its advocates in the counter-drug community believe these first cases will establish the law’s constitutionality.

Up to now, the developers of the SPSS – nobody knows for sure who is building them, though all available evidence points to Colombian cartels – have shown a remarkable willingness to write off the costs of the semi-submersible, which is rumored to be sunk after delivering its cargo. An SPSS costs an estimated $500,000 to $1 million to build. Its cargo, on the other hand, can be valued at anywhere from $200 million to $400 million.

Lt. Aaron Kowalczk, a senior law enforcement duty officer for the Coast Guard’s 11th District, said the new law places yet another obstacle in the path of drug traffickers who have been operating semi-submersibles with impunity. Since passage of the Drug Trafficking Vessel Interdiction Act, the Coast Guard has interdicted a total of 12 semi-submersibles on the high seas. “The majority of them did sink themselves, but all of those cases have either been prosecuted in U.S. court or are pending,” Kowalczk said. “Colombia [has] really stepped up their naval presence in enforcement in conjunction with us, and they interdicted – I don’t have the specific numbers, but quite a few semi-submersibles as well, either just offshore, just when they’re leaving, or they’ve actually gone into the jungle and found them at the build sites.”

From what Kowalczk has seen, the law and stepped-up enforcement have created a powerful deterrent. “So far in 2010,” he said, “we’ve seen a drastic decrease in the number of semi-submersibles on the water. Of course, that’s mostly led by the law, getting prosecutions. But also, every time we’re able to find one, that helps us refine our search techniques for them as well; we’ve also [gotten] more effective at detecting them. And so when you add the loss of the semi-submersible itself, which costs anywhere from several hundred thousand dollars to a million dollars to construct, plus normally four crew members going to jail, plus the loss of anywhere from 5 to 10 tons of cocaine – that method of conveyance is proving to be getting pretty costly for drug traffickers. Every one we catch would be a major financial blow.”

While U.S. counter-drug agencies would be happy to see the SPSS disappear from the Transit Zone, everyone expects some other means of conveyance to rise to prominence in its place. The tactics of traffickers always evolve along with the ability to catch them: The latest adaptations include liquid cocaine, in smaller amounts, in go-fast boats that hug the coastline and transit easily across international boundaries.

On July 2, 2010, the DEA had its suspicions about the traffickers’ next move confirmed when Ecuador anti-narcotics police and military forces, with the assistance of the DEA, seized a fully operational submarine in the Ecuadorian jungle whose primary purpose was allegedly the transport of multiple tons of cocaine. The first true “narco sub” ever seen by authorities was a sophisticated vessel, with a conning tower, periscope, and air-conditioning system.

The discovery of a genuine submarine caught nobody in the U.S. counter-drug community by surprise – but it was a clear demonstration that, with the possibilities for SPSS transports being methodically choked off in the Transit Zone, drug traffickers are willing to up the ante.

“The advent of the narco-submarine presents new detection challenges for maritime interdiction forces,” said DEA Andean Regional Director Jay Bergman after the discovery of the Ecuadorian sub. “The submarine’s nautical range, payload capacity, and quantum leap in stealth have raised the stakes for the counter-drug forces and the national security community alike.”

This article was first published in The Year in Homeland Security: 2010-2011 Edition.