An at-sea training mishap off the coast of Jacksonville, Fla. caused injuries to 30 Sailors and Marines, the U.S. Navy said.The incident, which occurred on the evening of May 1, involved two landing craft, air cushions (LCAC) from USS Wasp (LHD 1) and USS New York (LPD 21).Five Sailors were medically evacuated for further care at Savannah Memorial University Medical Center, officials said.