Nautilus was a schooner launched in 1799. The United States Navy purchased her in May 1803, renaming her the USS Nautilus; she thus became the first ship to bear that name. She served in the First Barbary War. She was altered to a brigantine. The British captured Nautilus early in the War of 1812 and renamed her HMS Emulous. After her service with the Royal Navy, the Admiralty sold her in 1817.