07 April 2025 US, Australian Naval Leaders Ride Submarine, Strengthening Bilateral Ties JOINT BASE PEARL HARBOR-HICKAM, Hawaii (Apr. 3, 2025) – Director of the U.S. Naval Nuclear Propulsion Program Adm. Bill Houston, who completed his Submarine Command Course training on Collins-class submarine HMAS Rankin in 2007, and Chief of the Royal Australian Navy Vice Adm. Mark Hammond, a 2003...