With three-quarters of potential cocaine shipments sliding under their noses, United States authorities are having a hard time keeping up with the Latin American drug cartels. Part of the problem, a new report in The New York Times says, is the fact that the famously daring and elusive drug-running submarines aren't just operating in the Pacific Ocean any more. These diesel-powered vessels have taken the Caribbean by storm, and the technology powering them is getting more sophisticated.

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Although they captured 129 tons of cocaine on its way to the U.S. last year, the Coast Guard thinks that close to 500 tons could now be making it through. "My staff watches multi-ton loads go by," Rear Adm. Charles D. Michel told The Times. Part of the problem is a new class of fully submersible craft, three of which have been seized in recent weeks. (Before, the subs were only semi-submersible, depending on a snorkel to bring in air for the engine.) These new drug-running subs are capable of carrying up to ten tons of cocaine at a time and can run from Ecuador to Los Angeles without coming up for air. On top of it all, officials are also worried that these subs could be used by terrorists.

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Of course, running drugs in subs is nothing new. So-called narco-subs first started making headlines about ten years ago when cartels, mostly Colombian at that point in time, started switching from the surface-level speedboat technique to using rudimentary fiberglass-and-wood vessels that could zoom under the surface. U.S. authorities called the first captured submarine -- a 49-foot-long vessel carrying four men, an AK47 and three tons of cocaine -- Bigfoot because they weren't even sure it existed until they spotted it. Since then the subs have only grown more sophisticated and more frequent, so U.S. authorities are working overtime. Michel says that drug interdictions are already up 50 percent in 2012. Success, as we mentioned before, is spotty at best.

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Success rates aside, the Feds know that they're dealing with a serious challenge. One commander working with a 600-person task force in Key West said that cocaine-filled subs "are the Super Bowl of counter narcotics." He told The Times, "When you hear one is moving you say 'Wow. Game on.'"