As World War I engulfed Europe the United States took the precaution of expanding the battle fleet. Nevada and Oklahoma were built first and enlarged and improved versions of these battleships came a year later, in 1915, with the sister ships Arizona and Pennsylvania. The new ships had a displacement of 33,100 tons, had an overall length of 608 feet, beam of 106 feet and carried a complement of 1,358 men. Most of the battleships in Pearl Harbor were moored, as usual, on the south-eastern shore of the north-eastern corner of Ford Island, Battleship Row. Arizona. was inshore of the repair ship Vestal at the northern end of the row, with only Nevada further north. At 0806 on 7 December Arizona was attacked with bombs by Kate aircraft from the Japanese carrier Hiryu. One bomb hit starboard of No.4 turret. At 0810 Kates from Kaga attacked and a bomb hit next to No.2 turret, entering the forward magazine which exploded, inflicting fatal damage on the ship. The report that a torpedo passed under Vestal and struck the battleship is incorrect. The First Battleship Division commander, Rear Admiral Isaac Campbell Kidd, and the captain of the Arizona, Franklin Van Valkenburg, both died either in the explosion or in the fires that followed. Van Valkenburg's Academy class ring was found in the ashes and returned to his widow. Arizona burned for hours, settling in the water and cutting the main water supply to Ford Island in the process, thus jeopardizing fire-fighting activity. Approximately half of the US Navy's casualties were suffered in this incident.The sunken battleship, part of her superstructure still standing above the waters of Pearl Harbor, is now the USS Arizona Memorial, a National Park Service site, open daily from 0730 to 1700 hours except special holidays. Telephone (808) 422 2771 or (808) 422 0561 for recorded messages.