USNS Prevail (IX 537) is a modified Stalwart class Auxiliary General Ocean Surveillance Ship (AGOS) of the United States Navy previously operated by the U.S. Military Sealift Command as T-AGOS 8. Prevail was reclassified as an "Unclassified Miscellaneous" (IX) ship in October, 2003 and is unofficially referred to as TSV-1. In this context, TSV stands for Training Support Vessel, and should not be confused with the U.S. Army's USAV Spearhead Theater Support Vessel initiative.