U.S. Navy Basic Crewman Training candidates tread water in a pool while waiting for instructions during their first physical screening test at Naval Amphibious Base, Coronado, Calif., May 11, 2009. The candidates are in their first week of Basic Crewman Training, which is the first phase of Special Warfare Combatant-craft Crewman training. SWCCs operate and maintain the Navy's inventory of state-of-the-art, high-performance boats used to support SEALs in special operations missions worldwide.