by Jennifer Steinhardt, NMAS Archivist
“Wise and humane management of the patient is the best safeguard against infection.” Florence Nightingale, the founder of modern nursing, certainly knew the difference having a designated hospital made in aiding in the recovery of patients. Historically, hospital ships helped to fill the need for a hospital to care for the sick and injured in locations where it was difficult or impossible to build a one on land. While records indicate that hospital ships were possibly utilized by the ancient Greeks and Romans, the United States Navy officially used its first hospital ship during the American Civil War.
The USS Red Rover was a steamer captured by the Union Army from the Confederate States of America. After a year of service as a Union Army hospital ship, USS Red Rover became the United States Navy’s first hospital ship. Staffed by nurses from the Sister of the Holy Cross, they were the first female nurses to serve aboard a Navy ship.

Line engraving after a drawing by Theodore R. Davis of the USS Red Rover in 1863. Courtesy of Naval History and Heritage Command
The United States Navy has used just over twenty hospital ships since the USS Red Rover. As wars expanded in size and scope, so too did the number of hospital ships. The Navy employed three active hospital ships during World War I. During World War II and its aftermath, the Navy operated fourteen hospital ships which actively providing support around the world. There are currently two hospital ships USNS Mercy (T-AH-19) and USNS Comfort (T-AH-20), serving the United States Navy.

USS Sanctuary (AH-17), a hospital ship during in Vietnam. Courtesy of Naval History and Heritage Command
While countries discussed the formal protection of hospital ships from capture or destruction during wartime as early as the 1860s, it was not until the 1899 Hague Convention that legal protections were formalized. . The convention established that vessels designated solely to be hospital ships “shall be respected and cannot be captured while hostilities last.” These protections were further fleshed out in the Convention (X) for the Adaptation to Maritime Warfare of the Principles of the Geneva Convention at The Hague on 18 October 1907, which enumerated that:
- Hospital ships cannot be captured while hostilities last and are not on the same footing as warships in regards to their stay in neutral ports.
- Privately-funded or officially recognized relief ships are also exempt from capture if they have an official commission from the belligerent Power to which they belong. Ships from neutral countries are also exempt from capture if they can certify their status.
- All hospital ships must offer relief to all wounded, sick, and shipwrecked sailors regardless of their nationality.
- Hospital ships may not be used for any military purpose and must not hamper movements of the combatants.
- Hospital ships must be distinguished from other vessels by being painted white. Military hospital ships are to have a horizontal green band while privately-funded and official relief hospital ships should have a horizontal red band. Hospital ships must fly a white flag with a red cross to further identify themselves as protected vessels.

USS Haven (AH-12) in San Francisco Bay, CA between July 1945 and May 1946 displaying the white surfaces, red cross, and horizontal stripe marking it as a hospital ship. Courtesy of Naval History and Heritage Command
While the 1907 Hague Convention’s protections were well-intended, they did not account for the changing nature of combat medicine. As seen during World War II, hospital ships evolved from helping those in the immediate aftermath of the battle to ferrying wounded combatants to hospitals on land. While white paint is easy to identify at close range during daylight hours, the means of maritime warfare changed. Long-range attacks by aircraft became the new normal, and hospital ships were sometimes misidentified as merchant marine vessels. The 1949 Geneva (II) Convention attempted to rectify these issues. The new protections maintained that hospital ships are protected at all times “and may in no circumstances be attacked or captured.” It also mentioned that the transportation as well as treatment of wounded military members was within the duties of a hospital ship. To help make hospital ships even more identifiable, the new rules stated that:
- All exterior surfaces should be white.
- At minimum, one dark red cross should be painted as large as possible on each side of the hull and on horizontal surfaces to have the greatest visibility from the sea and air.
- All hospital ships should hoist their national flag along with a white flag featuring a red cross flown as high as possible on the mainmast.

USS Haven (AH-12) almost ten years later on 19 January 1954, displaying the new hospital ship markings of three red crosses without horizontal bars to connect them. Courtesy of Naval History and Heritage Command
Hospital ships were further protected by the 1977 Protocol Additions to the Geneva Conventions of 1949 that stated hospital ships be identifiable to submarines by appropriate underwater acoustic signals transmitted in Morse code.

Navy Nurse Miss Lee entertains a Vietnamese child aboard the USS Repose (AH-16) for corrective surgery while the ship operated in the South China Sea in October 1967. Courtesy of Naval History and Heritage Command
In addition to providing aid during military conflicts, hospital ships also participated in humanitarian missions and provided additional medical services to communities. During the Influenza Pandemic of 1918, USS Comfort (AH-3) and USS Mercy (AH-4) were stationed in New York to help with overflow patients from the Third Naval District. Once again offering support during a pandemic, current hospital ships the USNS Mercy (T-AH-19) and USNS Comfort (T-AH-20) were stationed in Los Angeles and New York City, respectively, to provide additional medical support to these areas heavily-affected by COVID-19. The composition of a hospital ship crew changes depending on its mission and usually comprises of a mix of civilian and Navy medical personnel.

USNS Mercy (T-AH-19) providing humanitarian medical services in the Philippines in May 1987. The ship is currently in Los Angeles, CA providing support during the COVID-19 pandemic. Courtesy of Naval History and Heritage Command

Preliminary Design Plan for a Hospital Ship, February 1915; Courtesy of Naval History and Heritage Command
To this day, only the USS Relief (AH-1), serving from 1920 to 1946, was built from the keel up to be a hospital ship. The United States Navy converted a wide array of ships, including passenger vessels, troop transports, and supertankers, into hospital ships. The United States Navy’s current hospital ships, USNS Mercy (T-AH-19) and USNS Comfort, were originally San-Clemente-class oil tankers, the SS Worth and SS Rose City, respectively. Now, each ship has twelve fully equipped operating rooms, beds for 1,000 patients, blood banks, pharmacies, and more. They are fully functioning hospitals set afloat. If she could see these ships helping sick people around the world, Florence Nightingale would surely be proud.
Thanks, Jennifer
Very informative
Very interesting
Very well researched and written
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