USS PROTEUS (AS-19) was a Fulton-class submarine tender commissioned by the United States Navy in 1944. Initially serving in the Pacific Theater during World War II, she provided vital maintenance and support to submarines engaged in combat operations. After the war, PROTEUS was modernized and played a key role during the Cold War, especially by supporting ballistic missile submarines as part of the U.S. nuclear deterrent force. She remained in active service through several decades, supporting submarine operations in both the Atlantic and Pacific before being decommissioned in 1992.