Bay Area Coast Guard crew intercepts cocaine smuggling sub

(Suspects' images blurred by USCG) less Four suspected transnational criminal drug runners were aboard the blow-laden submersible about 300 miles southwest of Panama when the boat was spotted cruising just below the ocean surface. (Suspects' images ... more Four suspected transnational criminal drug runners were aboard the blow-laden submersible about 300 miles southwest of Panama when the boat was spotted cruising just below the ocean surface. Photo: US Coard Guard Photo: US Coard Guard Image 1 of / 23 Caption Close Bay Area Coast Guard crew intercepts cocaine smuggling sub 1 / 23 Back to Gallery

A Bay Area Coast Guard crew busted a group of smugglers piloting a covert submarine loaded with 6 tons of cocaine through the open waters off the coast of Central America, officials said Monday.

Four suspected transnational criminal drug runners were aboard the blow-laden submersible on March 3 about 300 miles southwest of Panama when the boat was spotted cruising just below the ocean surface.

A U.S. Customs and Border Protection airplane spotted the vessel and scrambled two interceptor boats with the crew from Alameda, Lt. Donnie Brzuska said.

Once on board, the Coast Guard team found 12,800 pounds of coke with an estimated street value of over $200 million along with a loaded gun in the cockpit, Brzuska said.

The suspected smugglers were apprehended without incident. The Coast Guard released video of the dramatic open-ocean raid, showing armed officers storming the simplistic craft.

The boat, a self-propelled semi-submersible, is one of scores of makeshift vessels that glide just below the ocean surface to smuggle drugs into the United States.

The vessels have a mostly submerged hull with a cockpit and exhaust pipe that stick out just above water, making them hard to detect because of their low profile.

The Coast Guard busted a similar boat southwest of the Mexican-Guatemalan boarder in January.

Last year the Coast Guard seized more than 319,000 pounds of cocaine from semi-submersible boats and so far this fiscal year, which began Oct. 1, the agency has taken more than 200,000 pounds of drugs from such boats, officials said.

Evan Sernoffsky is a San Francisco Chronicle staff writer. Email: esernoffsky@sfchronicle.com Twitter: @EvanSernoffsky