April 9, 2021: In southern Spain (Malaga province, just east of the Straits of Gibraltar), a March 2021 police raid on a drug gang coastal warehouse found a ten-meter (31 foot) narco-sub (drug smuggling submersible vessel) under construction and nearly completed. The sub had a fiberglass and wood hull containing twin 200 HP engines. The sub could carry about two tons of drugs. This type of narco sub is used for offshore transfers of drugs from ocean-going fishing trawlers or cargo ships carrying cocaine from South America or hashish and heroin from Africa. Belgium and Spain are major centers of the European drug trade and together account for about ten percent of the drug seizures worldwide.

Building narco subs in Europe was suspected after the long-anticipated appearance of South American narco-subs in Europe finally happened in November 2019. This occurred off the Spanish coast when a trans-Atlantic narco-sub was having engine and ventilation problems made worse by rough seas. The three-man crew was discovered by police as they were abandoning the sinking narco-sub close to shore. Two of the crew, both from Ecuador, were arrested while the third man got away but was captured a few days later and found to be Spanish and the pilot of the sub. The sub was soon brought to the surface and taken to a port. The 21-meter (67 foot) submersible was carrying three tons of cocaine and had apparently made several voyages so far. This one had traveled farther than usual, to northwest Spain, near the border between Portugal and Galicia (Spain), to avoid more intense offshore patrols off the southwest Spanish coast. The use of these submersibles off the Spanish coast had been rumored since 2016. It was also known that some only went as far as Cape Verde Islands (570 kilometers off the northwest coast of Africa), the Canary Islands further north (100 kilometers off the Moroccan coast) or much farther north to the Azores (1,500 kilometers west of Portugal). Once near these islands, the subs offload their cargo to fishing or speedboats, take on fuel and return to their South American base to pick up another load. As the use of submersibles and subs in South America became more common, it was suggested that these difficult to detect boats be used to move the cocaine to Spain.

Some submersibles had already been delivering cocaine to the west coast of Africa where smugglers moved it north and distributed some of it to African and North African gangs that serviced the smaller (than Europe) local markets. Most of this trans-Atlantic cocaine ends up in Spain which is the source of most cocaine distributed throughout Europe. Spanish gangs dominate the importation and distribution of cocaine to other European markets. There are hundreds of police investigators in Spain and Europe who concentrate on the Spanish gangs that are at the center of the very profitable European cocaine trade. The Spanish gangs arrange for pick up and movement of cocaine from the Atlantic islands to Spain or other European countries. What information the police have about the trans-Atlantic movement of the cocaine comes from interrogations of arrested gang members and eavesdropping on their electronic communications. For a long time, the cocaine was smuggled in aboard cargo or passenger ships or commercial airline flights. These methods involved a lot of people getting caught and many shipments, some of them quite large, seized. Operating these small narco-subs on the high seas proved more difficult at first. After some trial and error, including many subs disappearing at sea, narco-sub design and crew qualifications reached the point where trans-Atlantic voyages were deemed practical for regular use. Eventually, the majority of cocaine used in Europe was arriving via these small narco-subs.

The European police cooperated with their American and South American counterparts to get an idea of how extensive the use of these submersibles was in moving cocaine from the source (Ecuador and Colombia) to world markets. The submersibles had already become the major transportation method to North America, Africa and Europe because they were the most difficult to detect. Since the 1990s it is believed that nearly a thousand submersibles have been built and about two hundred are currently in use. That’s about a billion dollars spent on narco-sub construction.

The United States has been dealing with these submersibles since 2000 because most of them appeared to be used to move cocaine to the United States. Most (about 80 percent) of the submersible traffic was in the Pacific, from South America to Mexico and, less often, to Central America. Another 15 percent operated in the Caribbean and a growing percentage of the boats were moving cocaine to Africa and Spain.

Most of these narco-subs are still "semi-submersible" type vessels. These are 10-20-meter (31-62 foot) fiberglass and wood boats, powered by one or two diesel engines, with a very low freeboard and a small "conning tower", providing the crew (of 3-5), and engine, with fresh air and the ability to safely navigate. A boat of this type was, since they first appeared in the early 1990s, thought to be the only practical kind of “submarine” for drug smuggling. After 2000 some drug gangs developed real submarines, capable of carrying 5-10 tons of cocaine. These boats were not true submarines because they did not have batteries so they could operate submerged with the diesel engine turned off. Instead, these subs used a World War II innovation, the snorkel. This looked something like a periscope, but thicker in diameter. For narco-subs, the snorkel mast was not retractable, as it is on military subs, but operated on the same principle. In the smaller narco-subs, the snorkel proved to be more trouble than it was worth. In bad weather, with waves constantly washed over the snorkel and forced its water valve to close, so water did not get into the sub. This often caused the diesel to shut down because of insufficient fresh air and too much exhaust unable to vent. The crew had a separate air supply but that supply was not sufficient to keep the diesel going, even for short periods. The snorkel was largely gone by the late 1990s. Instead, the designs of the semi-submersibles were improved by using better methods to cool the exhaust via more pipes outside the sub hull where the colder water absorbed heat before venting in into the air via a curved pipe that sent the exhaust down towards the water rather than straight up. By reducing its “heat signature” this way, the sub reduced its vulnerability to the heat sensors search aircraft used. At that point the semi-submersible subs were very difficult to spot using radar, heat sensors, or even visually, from the air or a surface ship. With its reduced heat emissions, the snorkel was no longer an attractive alternative. The police and military have since obtained better sensors for detecting these narco-subs. The American military is a leader in this field and that is why the one percent detection rate increased to about ten percent of all narco-subs being detected and caught.

The snorkel subs also cost more than semi-submersibles and required a more highly trained crew. For a long time, there were efforts to borrow a lot of technology and ideas from the growing number of recreational submarines being built. That led to the construction of a few true subs, based on recreational subs. These proved to be more expensive to build and operate and some were still detected at sea or during construction. That meant the true subs were not sufficiently more effective to justify their higher cost. Semi-submersibles cost about $2 million to build, which takes about a year. The true submarines take several years to build and cost over $5 million.

That has led to drug gangs changing their tactics and building smaller narco-subs that carry one or two tons of cocaine (at $24 million a ton) so that if one of these subs is caught, its loss is just considered a cost of doing business and not a significant financial loss.

Despite losing over a hundred of semi-submersibles to the U.S. and South American naval forces, plus hundreds more to accidents and bad weather plus hundreds more to heavy use, the drug gangs have apparently concluded that the subs are the cheapest and most reliable way to ship the drugs. Early on, several hundred of these narco-subs were built and used on one-way trips to Mexico or the United States. Most of them got through. As new ones were built, their designs and durability improved to the point where the semi-submersibles were capable of multiple round-trips. Some have apparently been refurbished or rebuilt so they can undertake even more voyages. It was these sturdier and more reliable vessels that made the trans-Atlantic routes possible. The more reliable boats also made it possible to obtain more experienced, and effective, crews. The early designs were dangerous and although high fees were paid to crew, usually operators of offshore fishing boats, it was very dangerous. Some of the early crews were recruited by threats against their families or even by kidnapping of family members. With the reusable boats more crews were making a career out of this well-paying job. Moreover, the trans-Atlantic voyages meant covering about 8,000 kilometers, which could take 15-20 days. The trips to Mexico were less than half that and the ones to Central American or via the Caribbean even shorter. The early trans-Atlantic voyages went only as far as some islands close to Europe and Africa but these were still about 75 percent as long as going all the way to Spain.

A detection network, run mainly by the United States, located a lot more of these cocaine subs than there were police or coast guard or navy ships available to run them all down. This was a problem that has yet to be solved. It is complicated by the fact that these aerial contacts can be lost even if you keep the search aircraft in the area for a long time so a surface ship can arrive. One possible solution to this was more international cooperation. Since the early 1990s the United States has used a special interagency (Departments of Homeland Security, Justice, State, and Defense) and international (over a dozen nations participate) intelligence sharing/analysis operation (Joint Interagency Task Force-South) to track drug smuggling from South America. After 2001 the task force has become quite expert at tracking the submarines and submersibles built in South America for smuggling cocaine to North America and, in a few cases, all the way to Europe. Some of these long-range subs are apparently going all the way from Ecuador to the United States, bypassing the Mexican cartels, who have been fighting each other, in a big way, since 2008. Trips directly to the United States proved too dangerous and most of the narco-subs now go to Mexico or Central America.

There was always a concern that larger boats would eventually head for Europe. For years little was known about this effort, except that it existed. Then verifiable reports, from informants, electronic eavesdropping and interrogations confirmed that cocaine was coming in via semi-submersibles. It was believed that these subs would be more at risk of being lost because of an accident or bad weather than being spotted. It turned out that the new designs were even capable of making the trip and (usually) returning under their own power. European navies, especially Portugal's and Spain's, and coast guards were alerted and began searching regularly but until 2019 had never actually caught one of these semi-submersibles. At first, it was thought that the risk of failure was so high for these trans-Atlantic narco-subs that few were built and not on a regular basis. That was not the case and the captured gangsters and overheard electronic communications indicated that the subs had become a regular method for moving the cocaine.

So far, the Colombian security forces and other Latin American navies have been responsible for most of these vessel captures. The number being captured has been going up in the last few years and 2019 was a record year with 36 boats detected and seized. Usually these boats are sunk by their crews when spotted, but the few that were captured intact revealed features like an extensive collection of communications equipment, indicating an effort to avoid capture by monitoring many police and military frequencies. The Colombians have captured several of these vessels before they could be launched. Since 2010 the Colombians have been collecting a lot of information on those who actually builds these subs for the drug gangs and FARC (leftist rebels that provide security and often transportation for moving cocaine). FARC made peace with the government several years ago but some factions refused to surrender and continued to produce cocaine and build semi-submersibles. Security forces in Colombia and Ecuador continue to search for the jungle river banks where the construction takes place. These construction sites are constantly being moved because they are hard to keep hidden for a long time.

Colombian police have arrested dozens of members of gangs that specialized in building submarines and semisubmersible boats. As police suspected, some of those arrested were retired or on active duty with the Colombian Navy, which operates two 1970s era German built Type 209 submarines. These arrests were part of an intense effort to find the people responsible for building subs for cocaine gangs. Find the builders and you stop the building efforts. In this case, it has only delayed some construction and made it more expensive to build these boats.

European police have detected signs that Spanish drug gangs are not only building their own narco-subs for making the final run of from up to a hundred kilometers off shore, with cocaine transferred from a larger surface ship, but also planning to make fully submersible subs powered by electric engines for this final run to the Spanish coast. These would be larger than the usual narco-subs because of the need to carry over ten tons of batteries to propel the sub under water at about 60 kilometers at five kilometers an hour, just beneath the surface. These subs would be virtually undetectable compared to the current diesel-powered semi-submersibles, but would have to meet the ship carrying the drugs closer (under 30 kilometers) to the shore. These submersible subs would be far more expensive (over $10 million each) to build and require better trained and more experienced crew to operate it. For that reason it is believed the drug gangs will not take the risk of building and operating these more expensive and complex submersibles unless losses among the semi-submersibles off the coast get too high.

The U.S. is sharing with Israel what it knows about finding these vessels because Israel feels threatened by them for different reasons. In 2016 Israel began deploying new sensors and techniques to find these small, easily built vessels that they fear will be used to attack Israel’s new offshore natural gas fields. The Israelis have an advantage in that they have a less restrictive ROE (Rules of Engagement) and, while the United States never has enough surface ships or long-range helicopters to make sure that long-range sensor contacts are actually narco-subs and not some legal vessel, the Israelis can warn all maritime traffic in their coastal waters to identify themselves or risk being fired on from the air or from surface craft. A number of the latter are unmanned, like the new Seagull USV (unmanned surface vessel) that can fire wire-guided torpedoes.