`` They cost up to a million dollars to produce . Small boats can travel almost completely underwater , Coast Guard says . Semi - subs carry cargo from Colombia to U.S. million - dollar boats built in jungle , sometimes assembled elsewhere . They ' ve been around awhile , but now more sophisticated , carrying more cargo .
Small boats can travel almost completely underwater , Coast Guard says . Semi - subs carry cargo from Colombia to U.S. million - dollar boats built in jungle , sometimes assembled elsewhere . They ' ve been around awhile , but now more sophisticated , carrying more cargo .