USNS Comfort is a US Navy hospital ship operated by the Military Sealift Command, converted in 1987 from the San Clemente-class oil tanker SS Rose City. She is one of two US Navy hospital ships (with sister USNS Mercy) and provides a 1,000-bed mobile hospital capability deployable worldwide. The ship is crewed by a combination of MSC civil-service mariners and US Navy medical personnel. She has deployed for disaster relief (Haiti 2010, Puerto Rico 2017) and most recently for COVID-19 surge support (New York 2020, Los Angeles 2020).
Comfort is operated by Military Sealift Command — meaning a US-flag civilian mariner crew (not Navy active-duty for the ship-operating roles, distinct from the Navy medical staff embarked). MSC mariners on hospital-ship deployments work an unusual mission profile: long periods of standby, short bursts of intense humanitarian operations. Pay and benefits follow MSC scales rather than commercial merchant marine.
USNS Mercy