A New Underwater Threat

By Captain Wade F. Wilkenson, U.S. Navy

Maritime traffickers have a knack for discovering and exploiting vulnerabilities in counterdrug operations. Approximately 80 percent of the cocaine that departs South America travels by sea in the Eastern Pacific and Western Caribbean. 1 Over the years, traffickers have created intricate methods involving multiple at-sea transfers between commercial fishing vessels, complex logistics chains along circuitous routes, and extensive use of decoy vessels to confuse interdiction forces. In response, the United States and partner nations—Colombia, in particular—developed improved vessel registration and tracking systems that have successfully diminished the net profitability of using commercial fishing vessels to ship drugs.

Go-fast boats became a conveyance of choice in the late 1990s. These vessels can carry up to four metric tons of cocaine while racing at speeds approaching 60 knots, fast enough to out-run conventional interdiction ships. They also blend with peak weekend traffic, which makes sorting the drug-trafficker from the recreational boater difficult. In recent go-fast boat operations, traffickers flood the domain with many decoy boats, swamping limited interdiction resources. While this has been a highly effective tactic, cooperative strategies are in place to defeat go-fast trafficking. For example, Colombia and the United States routinely share intelligence and hand over tracking information to law enforcement agencies best suited to respond to any particular trafficking event. Advanced technologies such as over-the-horizon, high-speed interceptor craft, armed tactical helicopters, and non-lethal means to stop vessels have also enabled counterdrug forces to reduce the profitability of go-fast operations, forcing traffickers to seek new forms of smuggling. Uncommon ingenuity is a common characteristic of drug trafficking organizations, and the evolution of the SPSS makes the case in point.

Going for Stealth

The earliest types of semi-submersibles for drugs were sealable, ballasted containers towed behind ships and boats. Not carrying cargo on board gave traffickers the option to cut the tow and flee when threatened by interdiction. This method fell sharply out of favor after law enforcement learned to document the towing operation before approach, retrieve the contraband, and prosecute the smugglers.

Self-propelled versions emerged in the mid-1990s. Prototypes were nothing more than crude after-market adaptations of existing go-fast or Boston Whaler hull forms. Traffickers simply covered the vessels with camouflaged plywood or fiberglass to minimize visual detection from overhead air surveillance. Later, as traffickers studied what worked best, they began to build semi-submersibles designed from the keel up for optimal stealth.

SPSS vessels vary in design and construction but share common characteristics. Size and capacity range from 10 to 25 meters in length and 3 to 15 metric tons of cargo space. Generally made from wood framing and fiberglass, some designs include steel hull construction for better seaworthiness and durability. Although typically ballasted with tons of lead, concrete, or rock, newer versions provide means to change draft under way. By filling fuel tanks with seawater as they empty, they maintain a steady, ultra-low profile that make them nearly impossible to spot by eye at any distance over one nautical mile.

Range of an SPSS is about 1,500 miles, but some store enough fuel to travel twice that distance. A small conning tower allows a wave-top view for steering. Piping redirects diesel engine exhaust back toward the boat's wake to lower the infrared signature. Equipped with GPS, SPSS vessels navigate independently without need for external communication. They can cruise faster than eight knots but tend to operate at slower speeds to minimize wake detection. Such technological enhancements and tactics make the SPSS increasingly complex and better capable of defying surveillance and detection.

Who Is Building Them . . . and Why?

The Colombian Navy discovered a jungle shipyard located southeast of the port of Buenaventura in October 2007. At the site, two SPSS vessels were under construction. One was ready to launch, the other about 70 percent complete. Captured workers told the press that the narcoterrorist group, Revolutionary Armed Forces of Colombia (FARC), controlled the shipyard. While this incident represents the first known case of the FARC operating an SPSS shipyard, there is no clear evidence that the group is single-handedly responsible for large-scale SPSS shipbuilding. In fact, drug-trafficking organizations practice exceptional control of information regarding SPSS launch date, cargo, route, and destination. Hence, no one knows for sure who produces the majority of SPSS vessels. We can conclude, however, that SPSS construction is an extremely lucrative business.

In Colombia, for example, a kilogram of cocaine costs about $1,800. That same kilogram is worth at least $20,000 wholesale in the United States. Experts conservatively estimate that each SPSS costs roughly $1 to $2 million to build, equip, and crew, so a ten-metric ton SPSS, fully loaded, is a $20 million investment. Deploy five vessels at a combined total lay out of $100 million, successfully deliver one, and you double your investment. Having all five successfully reach their destination nets a nine-fold return on investment. Such astronomical profit potential drives innovation, allows ruthless thuggery to thrive, and encourages habits of waste.

They Are Expendable

Four or five men crew an SPSS, chiefly to serve as stevedores on arrival at the offloading destination. Yet, as well designed as the SPSS may be for evading detection, crew habitability is an afterthought. The SPSS is fitted with sleeping bunks but has no sanitary facilities or air conditioning. Fresh air enters through snorkel tubes that inadequately displace suffocating diesel fumes and stench from the bilge. Without navigation lights or surface search radar, the SPSS constantly risks being run over by an unsuspecting merchant or fishing vessel. By the end of a one to two week transit, conditions inside must be as unbearable as nerves are frayed.

These vessels typically deploy on a one-way mission. A series of quick-acting valves for use in rapid scuttling at the destination are central to SPSS design. Along with full cargo containment, rapid scuttling capability gives the craft a clear advantage over go-fast boats. At the slightest hint of a nearby law enforcement vessel, SPSS crews simply open the scuttle valves and bail out before interdiction can take place. In addition to rescuing the crewmembers, interdicting forces often find themselves racing on board an SPSS to retrieve evidence before the vessel sinks. Such attempts often end with the SPSS vessel breaking up and sinking within seconds of boarding, necessitating rescue of both crew and the interdiction team. Without evidence of illicit cargo to prove trafficking, current laws dictate release of the crewmembers free of charge. This may soon change.

This past July, the U.S. House of Representatives passed the Drug Trafficking Interdiction Act of 2008 (HR 6295). Currently awaiting action by the U.S. Senate, this new legislation will deter drug trafficking by criminalizing the use of unregistered, un-flagged submersible or semi-submersible vessels in international waters. It will also boost safety for interdiction forces, since they will no longer need to make heroic efforts to seize physical evidence from a rapidly sinking SPSS.

Monitoring and Interdiction

The President's National Drug Control Strategy aims to reduce drug demand while eliminating the supply of drugs through law enforcement and international cooperation. On the supply side, the Department of Defense does not play the lead role; rather, it supports U.S. law enforcement agencies by leading efforts to detect, monitor, and track the flow of drugs. Success requires a mix of sophisticated technologies, adaptive capabilities, and a wide variety of U.S. and international entities working as a team.

South American drugs headed for the United States pass through a six million square mile transit zone—an area about twice the size of the continental United States—which includes the eastern Pacific Ocean, Gulf of Mexico, and Caribbean Sea. In Key West, Florida, the Joint Interagency Task Force-South (JIATF-South) serves as the U.S. Southern Command component to integrate, facilitate, and synchronize interagency counterdrug operations, and is responsible for the detection and monitoring of suspect air and maritime drug activity in the transit zone. JIATF-South also collects, processes, and disseminates tactical information to many partner nations to enhance coordinated, multinational counterdrug operations.

JIATF-South supported record-setting cocaine seizures from 2001 through 2006. Then in 2007, maritime interdictions fell by 37 percent. Analysts blame the drop on three significant narcotrafficking changes: (1) a shift away from more vulnerable, bulk shipments toward smaller, more distributed loads; (2) increased use of the littorals crossing multiple territorial boundaries—a technique that stretches the capabilities of coordination and interdiction response; and (3) a dramatic rise in the use of SPSS vessels to transport drugs.

According to the Consolidated Counterdrug Database, SPSS vessels accounted for just over one percent of all maritime cocaine flow departing South America in 2006. 2 One year later, the SPSS share jumped to 16 percent. Between 2000 and 2007, drug traffickers launched 23 SPSS vessels. By the end of 2008, SPSS use will likely double. In the first six months of Fiscal Year 2008, more than 45 SPSS vessels departed Colombia, on track for 80 to 100 by the end of the year. So far, less than ten percent of known or suspected SPSS underway transits have been intercepted. Until authorities can disrupt significantly more of these deployments, the SPSS will remain a profitable and desirable link in the narcotics logistics chain and a serious threat. 3

Advantage: SPSS

The SPSS is effective because it combines the most desirable aspects of two historically successful methods of conveyance—the go-fast and the fishing vessel—while adding new dimensions to the drug challenge. Similar to the go-fast, its low profile is difficult to detect. Better than the go-fast, its range offers greater flexibility in planning potential drop locations. Similar to a fishing vessel, it has the capacity to carry larger, more profitable payloads. Better than a fishing vessel, traffickers launch them in secrecy, denying actionable intelligence that stymies counterdrug efforts.

The SPSS becomes particularly challenging for counterdrug operations when allowed open access to the sea. Because of its stealth, a single SPSS can tie up a variety of surveillance assets searching large areas of ocean. Although U.S. Navy, Coast Guard, and partner nation ships routinely patrol the transit zone, much of their success against drug traffickers relies on actionable intelligence. However, tactics and systems that work well against go-fasts and fishing vessels fail in the face of the SPSS challenge.

Experts estimate that SPSS vessels account for more than 30 percent of all maritime cocaine flow from South America to consumer markets, and it is a percentage that will likely increase. Recent captures, including one on 13 September that netted seven tons of cocaine with an estimated street value of $8.4 million, demonstrate that many of the basic building blocks are in place to stave off this swelling tide, but severe intelligence, detection, and interdiction gaps remain. The SPSS challenge demands a multi-faceted approach that includes increased international cooperation and interagency coordination, persistent wide-area patrol in the transit and source zones, active information gathering and sharing, and effective legislation to ease the burden of prosecution. Obviously lacking unlimited funding, we must prioritize resources toward achieving these goals.

Leaning Forward

As we get better at denying traffickers' means to transport drugs, they simply adapt and innovate. As the traffickers modify their strategy, we also continue to adapt and forge new initiatives that will curb the illicit drug market. Regrettably, this game of cat and mouse has allowed traffickers to stumble into a new domain with the SPSS. Having the capacity to carry tons of cargo and the capability to slip past authorities into the open ocean with near impunity, the SPSS has become more than a drug trafficking issue. To date, SPSS use has been limited to transporting cocaine out of Colombia, but the technology behind the SPSS is exportable.

Each year, the President's National Drug Control Strategy sets an interdiction target to disrupt a given percentage of all movement of cocaine through the transit zone toward the United States. In 2007, the goal was 40 percent of the 2006 total movement, or 365 metric tons of cocaine. In the counterdrug business, policy makers routinely benchmark success in this manner. Last year, for example, U.S. and partner nations achieved removal of 300 metric tons—82 percent of the goal. 4 A delta of 65 metric tons may seem reasonable, but seen from a different angle, the numbers are sobering.

According to the Consolidated Counterdrug Database, more than 1,400 metric tons of cocaine departed South America for destinations worldwide in 2007. At least 1,100 metric tons got through unscathed. Considering the impact of a single SPSS carrying a weapon of mass destruction reaching our shores, measures of success based on low percentages are inadequate. Against the SPSS, 100 percent success must be the standard—a high target, to be sure. In fact, we have never achieved anything close to that kind of interdiction rate to counter any mode of drug trafficking. Nevertheless, we must find the means to stop or deter the use of the SPSS in the interest of homeland security. At U.S. Southern Command, Admiral Jim Stavridis understands the underlying threat the SPSS presents, but more important, he sees an opportunity to meet the challenge bow on. Overall, the task may seem daunting, but we fail as soon as we accept it as insurmountable.

In seeking an answer to the SPSS challenge, imagine two diametric extremes. First, we could hypothesize that perfect maritime domain awareness is the best counter to the SPSS. This would involve developing a foolproof barrier of distributed underwater, surface, air, and space sensors across the vast expanse of the transit zone. Wide-area surveillance, identification, and sorting would eliminate the need for cueing information. A vessel could not possibly get through undetected. Interdiction force distribution and number would depend on the speed with which assets could respond to detection of an identified suspect vessel.

On the other hand, we might argue the antithesis: perfect knowledge of every SPSS event is the most effective way to defeat the SPSS. By putting our greatest effort toward developing actionable intelligence (i.e., infiltrating drug trafficking organizations, monitoring river entrances and choke points, and providing means to readily pass information), we would have exact cueing on every SPSS event. Thus, we could concentrate interdiction forces at strategic locations along known routes, or better yet, preempt SPSS construction altogether.

The Best of Both Worlds

In their purest forms, the ends of the dialectic are ideal but unattainable. Yet, they provide good theoretical bounds to discuss a wide range of middle options, or a solution that proves the best synthesis of both worlds. For example, full-scale maritime security covering the entire six-million square mile transit zone may be unachievable, but narrow the focus toward SPSS detection in the 1,800 miles of territorial waters along the Colombian coast, and we reduce the search volume to less than half of one percent of the transit zone—a considerably smaller problem set.

Every effort made toward aiding a willing, like-minded partner in the fight against the SPSS is money and time well invested. In the last eight years, the United States has provided $6 billion in funds, material support, and training to Colombia for the fight against drugs and terrorist organizations—less than half of what the U.S. government spends each year in the war on drugs. In return, the Colombian Navy and marine corps conduct extensive interdiction operations along the Caribbean and Pacific coasts and in the interior waterways of the Pacific lowlands.

Arguably, no country has demonstrated more determination to eliminate drug trafficking to the United States than Colombia. U.S. Southern Command and JIATF-South, along with our interagency partners, remain steadfast in our support of Colombia's counterdrug efforts. Together we are working hard to find innovative technological solutions to detect, identify, and track SPSS vessels; to share intelligence in support of surveillance and detection; to locate SPSS shipyards hidden by dense foliage; to train Colombian armed forces leading operations against narcoterrorists; and to assist interdiction and prosecution of SPSS crews. This stands the best chance to contain SPSS proliferation, and it provides a valuable test bed for technology, tactics, and procedures that have applicability to our own homeland maritime security. While no single effort is in itself a solution, mutually supportive relationships between partners, like that between the United States and Colombia, are imperative to building a path toward success against the SPSS and, ultimately, against the illicit drug trade.


1. Cocaine flow trends update for 2007, Consolidated Counterdrug Database (CCDB), 15 February 2008.

2. The Consolidated Counterdrug Database (CCDB) is a comprehensive data collection effort that captures the details surrounding every drug-related event submitted by U.S. and foreign counterdrug agencies. International and interagency partners gather quarterly to review all reported interdiction cases and vet the information for input into the database. They also revise, de-conflict, and validate data on overall counterdrug performance, trafficking trends, and regional cocaine flow. The information processed provides timely feedback for each participating agency to modify interdiction strategies and manage resources.

3. As previously discussed, assuming that successful delivery by one out of five SPSS vessels doubles initial investment. At least 80 percent interdiction, preemption, or deterrence would be required to dip into the profitability behind building SPSS vessels.

4. National Drug Control Strategy , 2008 Annual Report.

Captain Wilkenson is a surface warfare officer and a 1986 NROTC graduate of Northwestern University. He recently commanded the USS The Sullivans (DDG-68), and is currently serving as special assistant to Admiral James Stavridis, Commander, U.S. Southern Command.


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