The Haven class of hospital ships was built for the United States Navy (USN) during World War II. Haven-class ships also served in the Korean War and the Vietnam War. They were among the first ships to be able to receive casualties directly by helicopter and were the first fully air conditioned ships in the USN. The first ship was laid down in July 1943, while the last was launched in August 1944. In that span the United States produced 6 Haven-class hospital ships. The class was based upon the Maritime Commission’s Type C4 ship (as C4-S-B2 design).