Nautilus II, a 66-foot motor pleasure boat, was built at City Island, New York, in 1917. Leased by the Navy in August of that year, she was commissioned in October 1917 as USS Nautilus II (SP-559). She served as a patrol craft in the New York City area for the rest of World War I and for a few months afterwards. Nautilus II was decommissioned and returned to her owner in February 1919.