Niagara was laid down on 14 November 1928 as the steel-hulled civilian yacht Hi-Esmaro by the Bath Iron Works, Maine, launched on 7 June 1929, and delivered on 20 August.Niagara got underway from New York on 4 February 1941 to tend units of Motor Torpedo Boat Squadron 2 operating between Miami and Key West, Florida, and Guantanamo Bay, Cuba.She departed Key West on 20 March 1941 for repairs at New York and operations at the Naval Torpedo Station, Newport, Rhode Island during the summer.Niagara stood out from New York on 30 August 1941 en route to Hawaii, via Guantanamo Bay, the Panama Canal, and San Diego, arriving at Pearl Harbor on 9 October to patrol on the Hawaiian Sea Frontier.During an overhaul in the New York Navy Yard in the summer, she fitted out to serve at Newport, Rhode Island, as a school ship for a training squadron of motor torpedo boats.Niagara, in the thick of the fight, was north of the harbor, moored to the west bank of the Maliali River, heading downstream with minesweeper Rail (AM-26) tied up outboard well aft.Three near-misses to starboard and one to port damaged Niagara's sound gear and the training mechanism of one 3 inch gun and knocked out steering control temporarily.