The Helianthus III was a yacht, built by Nathanael Greene Herreshoff (1848âÂÂ1938) in 1924. She was a ketch-rigged wooden vessel, 62ý' long on deck with a 13'-9" beam and 4'-6" draft. Before being lost at sea in the 1990s, she was docked at Annapolis, Anne Arundel County, Maryland.
She was listed on the National Register of Historic Places in 1984.