{"nrhp_refnum":"99000609","name":"SS UNITED STATES (Steamship)","other_names":["U.S. Maritime Commission No. 2917"],"category":"structure","location":{"address":"Pier 82","address_restricted":false,"city":"Philadelphia","county":"Philadelphia","state":"PA","lat":39.91806634300008,"lon":-75.13652054899995,"geom_source":"nps_gis"},"listed_date":"1999-06-03","is_nhl":false,"nhl_designated_date":null,"areas_of_significance":["Engineering"],"significance_levels":["national"],"summary":{"what_it_is":"The SS United States is an ocean liner moored at Pier 82 in Philadelphia, Pennsylvania, completed in 1952 at the Newport News Shipbuilding and Dry Dock Company in Newport News, Virginia, to a design by William Francis Gibbs of Gibbs & Cox.","why_significant":"The nomination argues the ship is significant for its engineering: a longitudinally framed steel hull, extensive use of aluminum in the superstructure, a high-pressure steam turbine propulsion plant, and redundant systems for safety. It also presents her as the fastest and most powerful merchant ship of her era and as the culminating work of Gibbs's career. The property is nominated under Criterion C and Criteria Consideration G because its significance falls within the past fifty years.","narrative":"Built as an ocean liner at Newport News, Virginia, and completed in 1952 to a design by William Francis Gibbs, the ship is a steel hull with aluminum superstructure, roughly 990 feet overall and 53,329 gross tons. Its propulsion used four Westinghouse two-stage steam turbine sets driving 18-foot propellers, with separate boiler and engine rooms duplicated for redundancy. The ship set the Atlantic passage record on her maiden voyage in July 1952 and served the New York to Southampton route for seventeen years. Its longitudinal framing, subdivision into four compartments, fireproofing and large use of aluminum are cited as innovations that influenced later ship design. The ship is listed for its engineering achievements, and the nomination presents it as the culmination of Gibbs's career. Much of the interior has been stripped, but the propulsion, boilers, generators and structural framing are described as intact.","period_of_significance":"1952","architect_builder":"William Francis Gibbs (architect); Newport News Shipbuilding and Dry Dock Company (builder)","architectural_style":"Ocean liner","criteria":["C"],"status_note":"Moored at Pier 82 in Philadelphia; interior passenger fittings removed and lifeboats and davits missing, while engineering areas remain intact.","vacant_flag":null,"machine_generated":true,"model":"claude-haiku-5-5","prompt_version":"v1.1-2026-10-29","generated_at":"2026-10-29 17:11:36.561138-05","source_pdf":"https://s3.amazonaws.com/NARAprodstorage/lz/electronic-records/rg-079/NPS_PA/99000609.pdf"},"photo":null,"district":null,"sources":{"nps_snapshot_date":"2026-05-22","nara_catalog":"https://catalog.archives.gov/id/71997468","wikipedia":"https://en.wikipedia.org/wiki/SS_United_States","wikidata":"https://www.wikidata.org/wiki/Q1545509"},"indexable":true,"url":"https://nationalhistoricalregister.com/pennsylvania/philadelphia/ss-united-states-steamship-99000609/"}