Hospital ships open their doors to anyone who requires medical assistance (only if activated) per the second Geneva Convention of 1906 and the Hague Convention of 1907. In accordance with these, hospital ships and everybody on board enjoy a special status that protects them from any attack as long as it observes the restrictions stated in the conventions. Below are some of the conditions outlined in Article Four of the Hague Convention X:

  • Ships must be clearly marked and lighted as a Hospital Ship;
  • Ships should give medical assistance to wounded personnel of ALL nationalities;
  • Ships must NOT be used for any military purpose;
  • Ships must NOT interfere with or hamper enemy combatant vessels;
  • Belligerents, as designated by the Hague Convention, can search any hospital ship to investigate violations of the above restrictions;
  • Belligerents will establish the location of a hospital ship.

The US operates two active hospital ships under the US Navy, managed by the Military Sealift Command (MSC) since the 1980s. Since the vessels are non-commissioned properties, they’re given the prefix USNS or the United States Naval Ship instead of the USS (United States Ships).

Converted Oil Tankers

The USNS Mercy is the third largest ship in the US Navy Fleet by length and is the third ship to carry the name Mercy. Shipbuilding company NASSCO initially built USNS Mercy as a San Clemente-class super tanker (SS Worth MA-299) in June 1974 but was later converted to a hospital ship for a price tag of more than $208 million. After 35 months, Mercy was finally commissioned into service in the US Navy, dating November 8, 1986. As a leading hospital ship of her class up to date, the T-AH 19 features a raised forecastle, a transom stern, a bulbous bow, an extended deckhouse with a forward bridge, and a helicopter-landing deck with a flight-control facility.

USNS Mercy T-AH 19
USNS Mercy (Image source: US Navy MSC)

On the other hand, the USNS Comfort came months after her sibling was built, and just like Mercy, Comfort was built as a San Clemente-class oil tanker (SS Rose City MA-301) with its keel first laid down in May 1975. The hospital ship was handed over to the US Navy and commissioned on December 1, 1987, more than a year after its conversion.