Capture of “Bigfoot”

The Coasties had for some time heard scuttlebutt and discussed semi-submersible submarines carrying heavy loads of cocaine. The subject was discussed so much that they nicknamed it “Bigfoot.” 

Back in November 2006, the crew of USCG Cutter (USCGC) Steadfast (WMEC-623) saw something about 100 miles off the coast of Costa Rica and closed in. They then spotted three snorkels above the water. On this day, the Steadfast crew found “Bigfoot." 

She was a 49-foot handmade, self-propelled semi-submersible carrying four men, an AK-47, and 2.7 tons of cocaine. Such a vessel is often called an SPSS. The USCG refers to them as low-profile vessels (LPVs). Bigfoot is currently on display in Key West.

The media and many of us call them “narco-subs,” a phrase that grabs one’s attention. But SPSSs or LPVs are not submarines. 

While most of their hull is below the waterline, there is an upper structure that is above the waterline.

The design  so that almost nothing is visible above the waterline. They are usually made of fiberglass and wood and are self-propelled. These materials can elude radar. They are painted to blend in with the seawater. They are easy to build, and construction sites are hidden in the jungles, many in western Colombia, though shipyards have been found in Brazil, Venezuela, Guyana, and Suriname.

This particular vessel, discovered in 2006, had three snorkels above the waterline, but others have run exhaust fumes through pipes under the boat, which helps them avoid infrared detection. Often, these pipes are coated with asbestos to further reduce the infrared signature. Some of the boats have had lead shielding to reduce that signature further.

Bigfoot II was intercepted by the USCG in September 2008 by a USN frigate on Coast Guard duty, about 350 miles from the Mexico-Guatemala border. This narco-sub had a crew of four and 6.4 tons of cocaine. The estimate at the time was that about 100 narco-subs had been manufactured.

Over the years, designers have built long, narrow boats that slice through the water, leaving little wake. Most are powered by diesel engines. They have to surface periodically to recharge their batteries.

Use of GPS navigation has extended LPV reach. GPS enables precise route following, waypoint planning, refueling stops, and long-range voyages of 1,200 to 2,000 miles. It allows pre-programmed routes, accurate arrival and rendezvous points, and drop areas for later pickup.

LPVs have been fitted with hydroplanes to trim running depth and keep the nose almost completely submerged. Engines have been enlarged to extend the range. They often use a thin layer between the wooden deck and fiberglass to reduce radar detection.

Older models have a compass and small windows to support dead reckoning and manual helm control. They avoid high-traffic areas. Routes will depart from a South American location, stop at various locations in Central America, and then head to the US.

These semi-submersibles have scuttling valves that allow the occupants to sink the vessel and its contents while enabling them to float free. This forces the USCG to launch a Search and Rescue (SAR) mission, resulting in the occupants being returned to their country of origin.

Adding to the difficulty of detecting and seizing these LPVs is that they sometimes tow “torpedo cargo pods.” This increases the overall load of narcotics and/or weapons. The smuggler can cut the pod loose if threatened by boarding. The pod will sink and remain submerged for a couple of days, after which it will surface and transmit a radio beacon to reveal its location to the smugglers. Sometimes pleasure boats will come by and pick up the load without arousing suspicion.

Or, a torpedo cargo pod can be ,such as was discovered in Rotterdam Port, The Netherlands, in 2013, with 223 lbs of cocaine.

Most LPVs are used only once and then scuttled. It is easier for smugglers to ditch an LPV than to try to return it home.

There are multiple LPV designs. They can carry as much as 10-tons of cocaine depending on design,

• Hand-built LPV with diesel and electric engines, in-board and outboard.
• Long, slender boats with a narrow beam have been called Very Slender Vessels (VSV), outboard engines
• Autonomous, remotely operated LPV, surface and fully submersible
• “Narco-torpedo” dragged underwater by a ship, or towed containers

There is also concern about fully submersible vessels (FSV), to wit, a real submarine, sort of; it can only operate in shallow water. 

Ecuadorian police found an FSV in 2010 in swamps near the Colombian border. It was equipped with a conning tower, periscope, and air conditioning. It was 73 ft. long, camouflaged, fully submersible, long-range, and capable of carrying seven tons of cocaine. It could accommodate a crew of four or five and travel at 20 knots. Like diesel submarines, it would have to surface to recharge its batteries.

Ecuador is not known for producing cocaine, but Ecuadorian President Daniel Noboa has said that 70% of the world’s cocaine flows through his country’s ports, mainly Guayaquil. It appears that over 90% of cocaine movement originates in Colombia and Mexico.

In 2020, Colombian authorities and the Drug Enforcement Agency (DEA) discovered a battery-powered FSV. The vessel was to be towed by a larger ship so it could complete its final voyage on batteries. In 2022, another FSV was discovered while transiting the Arauca River in central Venezuela.

Moving drugs is one thing. The more troubling concern is whether the semi-submersibles might carry terrorists and weapons, particularly weapons of mass destruction (WMD).

Indeed, building and deploying these vessels, and finding and seizing them, has become a technological race. Most have been found on rivers, supported by a network of refueling stations and fishing boats. LPVs have been fitted with hydroplanes to trim running depth and keep the nose almost completely submerged. Engines have been enlarged to extend range. I mentioned earlier the use of lead, usually a thin layer between the wooden deck and fiberglass, to reduce radar detection.

Interviewed in 2019, Lt. Commander Stephen Brickey, USCG, told CNN that LPVs were relatively rare and very difficult to detect. He said, “They blend in. Most of the vessel is underwater, so it’s hard to pick out. They’re painted blue. They match the water.” He added that when they are found, they are usually carrying huge loads of drugs.

Twenty-five LPVs were interdicted in 2024. Most go undetected, about 85-90 percent. Estimates are that about 30 percent of the cocaine shipped is carried aboard LPVs.

US actions

A dominant issue for US authorities is that drug smugglers have a very sophisticated intelligence network. Michael Brown has written,

“The key to the cartels’ success is an extensive human intelligence (HUMINT) network and expert manufacturing skills … Drone incursions into American airspace to track the movement of CBP and police teams, for example, have become common … 

“Their operatives are deeply embedded in various Mexican industries, from telecommunications to manufacturing and transportation. They are tasked with relaying any relevant information that the cartels could use to manage their own risks, pivot their smuggling processes or implement ‘tactics’ to take care of imminent threats. Additionally, many operate in vehicle manufacturing or servicing businesses to assist in designing hidden compartments in vehicles or trucks, known as ‘traps.’"

As you might expect, the USCG has been conducting intensive counter-drug operations in both the Eastern Pacific and Atlantic (Caribbean) regions. It launched Operation Pacific Viper in August 2025. Estimates indicate that 74% of cocaine entering the US comes through the Eastern Pacific.

The USCG has a time-honored skill set for boarding vessels that dates back to the 18th century.

US Navy (USN) and Allied naval ships often carry Law Enforcement Detachments (LEDET) to intercept suspected vessels. The LEDET is a USCG team authorized by Congress to conduct law enforcement and maritime interdiction operations aboard naval ships. These Coasties are trained for high-risk operations.

The U.S. Southern Command (SOUTHCOM) has established the Joint Interagency Task Force-South (JIATF-S) at Naval Air Station (NAS) Key West. It leads Campaign Martello (Hammer), a U.S., European, and Western Hemisphere effort targeting illicit trafficking routes in coastal waters along the Central American isthmus. It serves as a central hub for intelligence on drug smuggling. 

In short, it is a multi-source intelligence fusion center. It has access to all-source intelligence, “long coveted by law enforcement agencies.”

The nickname PLUTO was used in 2008 for a US-built LPV serving as a target to test detection systems and train operators. It is 45 ft. long, operates at four to ten knots, and can carry a crew of three to four. PLUTO is home-ported at Eglin AFB near Fort Walton Beach and is maintained by the USAF.

Admiral James Stavridis, USN, has written,

“Criminals are never going to wait for law enforcement to catch up. They are always extending the boundaries of imagination, and likewise, we must strive to push forward technology and invest in systems designed specifically to counter the semi-submersible. We need to be able to rapidly detect and interdict this new type of threat, both for its current effects via the drug trade, and – more troublingly – for its potential as a weapon in the hands of terrorists.”

The US Congress passed the Drug Trafficking Vessel Interdiction Act of 2008, which stipulates that it is illegal to operate or embark on a SPSS without nationality in international waters with the intent to evade detection. It also requires anyone with an LPV to register it.

USN P-3 Orion maritime surveillance and anti-submarine aircraft have been converted into Long-Range Trackers (LRT) equipped with X-band Doppler radars, SeaVue marine search radar, EO sensors with night vision, digital zoom, and video recording. The SeaVue radar provides extended range and small-target detection from operational altitudes.

The USN P-8 Poseidon maritime surveillance aircraft fly off both coasts of Mexico and Central America, hunting for such submarines in addition to their mission to find and track military submarines. It has an APY-10 synthetic aperture radar (SAR) imaging system capable of detecting wakes left by LPVs. It can detect small targets such as skiffs and swarms of craft, even through sea clutter. It also carries deployable sonobuoys that can detect and locate LPVs and EO sensors.

Challenge, board and search: A scenario

“Get ‘em”

A case can begin when the DEA provides actionable law enforcement intelligence to the JIATF-S. It might then deploy a Customs and Border Protection (CBP) P-3 or USCG C-130 to detect and track a suspected foreign vessel. JIATF-S might then alert a USCG cutter or USN or Allied naval ship with a Law Enforcement Detachment (LEDET) to intercept the vessel.

The following describes a detection and boarding scenario shown on YouTube. I draw from it.

The scenario begins with a USCG HC-130J long-range surveillance aircraft, callsign “Viper One,” crew spotting a faint radar contact on the surface. The crew considered it a suspicious craft because of its slow speed of eight knots. The radar operator tagged it as an unidentified LPV heading along a known cocaine corridor from Colombia toward Mexico. The crew switched to infrared and synthetic aperture radar and estimated it was about 20 inches above the sea surface. 

The USCG Cutter Seneca was 50 miles away and estimated it would take 2.5 hours to intercept. That was too long, but the Seneca continued toward the intercept point anyway.

Viper One contacted Seneca and provided an “authorization Green,” which meant that Seneca could launch an MH-65 helicopter. The MH-65 was launched, and the estimated intercept of the target, which was 150 miles away, was one hour, with three-and-one-half hours of total flight endurance.

Viper One remained in orbit overhead, confirming the target’s course and speed. The MH-65’s radar lit up at 40 miles from the target, barely detectable, but at 20 miles the target was solid on the radar.

The MH-65 pilot then announced “visual contact” with the target at one-half mile out. The MH-65 descended to 200 ft. and settled into a hover over the target. The gunner was in position, but his machine gun jammed and locked. It could not be aimed. The MH-65 had two hours of endurance left.

The pilot rolled the MH-65 sideways in a “crab hover” and aligned the machine gun with the target. The gunner fired, and his first burst landed 100 meters in front of the target LPV. The second burst was 50 meters, then 10 meters, close enough to disturb the hull. Then the LPV’s motors shut down, and the target drifted.

The MH-65 now had about 90 minutes of fuel remaining. The HC-130J remained on orbit. About 12 minutes later, Viper One spotted two fast boats on his radar, on a vector directly toward the target. They approached side-by-side. Viper One notified the MH-65. They all knew this was standard smuggler procedure to provide protection for the LPV. The MH-65 climbed to 300 ft and orbited.

The MH-65 pilot once again tilted the aircraft to point the machine gun. The fast boats continued their approach. One veered off, but the other continued to protect the LPV. 

For the next 15 minutes, the “dance” continued, the fast boats moving about while the MH-65 kept its nose pointed at them. The gunner worked his locked machine gun and got it to budge just enough to enable him to fire at the closest fast boat, tracers hitting the water about 50 meters ahead of the fast boat.

Both fast boats backed away. The MH-65 held position on orbit. Viper One reported that Seneca was about 80 minutes away and approaching. 

The fast boats then resumed their approach and closed fast. The MH-65 rose to 500 ft. and remained tilted such that the fast boats understood he was going to fire again. The fast boats broke off and retreated. 

The MH-65’s fuel was running low. Then, Seneca came on the radio and advised he was on-station. However, the seas were building fast as a storm approached. Seneca’s crew activated their crane, and a crew member positioned himself in the seven-meter Rigid Hull Inflatable Boat (RHIB). The crane hoisted the RHIB, and the crane operator watched the ebb and flow of the waves building. He timed his hoist so the RHIB would land between wave crests, and it dropped about six feet into the water below.

The RHIB operator hit the throttle before the next wave arrived and, in seconds, was racing toward the LPV at 20 knots. Both Viper One and the MH-65 remained on orbit above. 

The coxswain on the RHIB aimed directly at the LPV and, at the last moment, pulled back the RHIB’s throttle, causing the RHIB to swing its side into the LPV's side. 

The first boarding officer, carrying 40 lbs of gear, jumped from the RHIB onto the wet and slippery LPV, timing his jump to the wave action. He found his footing, raised his weapon, and the second officer followed, then the third. The LPV was only three meters wide and awash with seawater.

The LPV crew of three knew it was over, climbed out of the LPV, and were restrained by the three Coasties on board. They quickly looked down into the cockpit and estimated three tons of cocaine.

The MH-65 called Seneca and said, “Mission complete. Returning to ship.” The Seneca skipper aligned the cutter to allow the MH-65 to land, and it did so with less than 50 gallons of fuel remaining. The cutter’s crew secured the helicopter. 

The RHIB towed the LPV toward the Seneca. The captain’s log read, “Routine interdiction. Three crew members captured. Three tons of cocaine aboard.”

Now, that crew can Talk Proud!