Prevail (IX-537)

Prevail (IX-537) is a modified 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 Unclassified Miscellaneous (IX) 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.

Prevail is currently assigned to Commander, Carrier Strike Group Four and is operated with a minimal, hybrid crew of civil service and contract mariners. The ship provides a dedicated training support for Strike Group training for U.S. Atlantic Fleet ships, including serving as a platform for training Visit, Board, Search, and Seizure (VBSS) operations.

Stalwart-class ships were originally designed to collect underwater acoustical data in support of Cold War anti-submarine warfare operations in the 1980s.