SAN DIEGO - U.S. Coast Guard crews Thursday offloaded more than 39,000 pounds of cocaine confiscated from seafaring traffickers over a record-setting 12 months, during which the maritime agency intercepted about $5.6 billion worth of the illicit drug.

During a briefing aboard the docked cutter Waesche at Naval Base San Diego, USCG officials detailed the seizure of roughly 416,000 pounds of cocaine off the coast of Central and South America during the just-ended fiscal year.

About 5,600 pounds of the haul was nabbed Sept. 6 from a self-propelled semi-submersible vessel, a type of watercraft specifically built for illegal trafficking because its low profile makes it difficult to detect.

The five smugglers aboard the hybrid boat tried in vain to sink it as authorities closed in.

"Our coast guardsmen face significant risks posed by dangerous criminal organizations," said Capt. James Passarelli, commanding officer of the Waesche. "Our crew preserved valuable evidence and kept millions of dollars of illicit narcotics off America's streets."

Additionally, the personnel captured 585 suspected drug smugglers -- also a record for the agency -- during the period, officials said.

Each at-sea interdiction helps authorities "learn more about transnational organized-crime networks that generate profit and proliferate power from a laundry list of illicit activities," said Vice Adm. Fred Midgette, USCG Pacific-area commander.

"Coast Guard men and women not only keep drugs off U.S. streets, but they combat the influence of these criminal networks that spread violence and instability throughout the Western Hemisphere," Midgette said.