 As built , Yorktown was 244 feet 5 inches ( 74 @.@ 50 m ) in length and 36 feet ( 11 m ) abeam . Her steel hull had an average draft of 14 feet ( 4 m ) , which was expected to give her the ability to escape from larger ships into shallow water . At the waterline was a turtleback deck of ⅜ -inch ( 9 @.@ 5 mm ) steel that formed a watertight seal over the lower spaces . The deck had a crown at the level of the waterline and curved downwards to 3 feet ( 0 @.@ 91 m ) below the waterline at the sides of the ship . Below this armored deck were twelve compartments separated by watertight bulkheads ; the spaces above were equipped with watertight doors intended to be closed during battle . 
