Premise: USFC "Fish Hawk" was a fisheries research ship operated by the United States Commission of Fish and Fisheries and its successor, the United States Bureau of Fisheries, from 1880 to 1926. She was the first large ship purpose-built by any country for the promotion of fisheries, and spent her 46-year career operating along the United States East Coast, in the Gulf of Mexico, and off Puerto Rico.
Hypothesis: Fish Hawk was the first large ship purpose built for the promotion of fisheries, and she operated for close to 50 years