The USNS MERCY (T-AH 19) was originally built as an oil tanker. Then in 1986, the ship was converted into a floating hospital. “Her primary mission is to provide rapid, flexible, and mobile acute medical and surgical services to support Marine Corps Air/Ground Task Forces deployed ashore, Army and Air Force units deployed ashore, and naval amphibious task forces and battle forces afloat. Secondarily, she provides mobile surgical hospital service for use by appropriate US Government agencies in disaster or humanitarian relief or limited humanitarian care incident to these missions or peacetime military operations.” wikipedia.org The 894 foot ship boots a fully operations ER, a ICU unit, 62 bed ward and a 22 bed hotel. In addition, the floating hospital has physical therapy and burn care units, dental services and a optometry lab.
http://www.youtube.com/watch?v=l3ISUXnlh0s&feature=related
Hospital Ship Mercy – Under Fire In The Philippines