NOAA Ship Townsend Cromwell was built by the J.Ray McDermott Company in Morgan City, Louisiana. Commissioned in June 1975, the ship’s main operation included fishery and living marine resource research in support of the NOAA National Marine Fisheries Service's Honolulu Laboratory in Hawaii. The ship normally operated in the Central Pacific Ocean and around the Hawaiian islands to collect fish and crustacean specimens using bottom trawls, longlines and fish traps.

The ship was named after Townsend Cromwell who was an oceanographer at the Pacific Oceanic Fishery Investigations in Honolulu, Hawaii. He is known for discovering the Cromwell current—a subsurface current that flows eastward and extends the length of the equator in the Pacific Ocean.