Uncas—a screw steamer built at New York City in 1843—was purchased by the Navy there on 20 September 1861 from Dudley Buck for use with the United States Coast Survey.

As a result of the havoc created by the resurrected Merrimack, Uncas was sent to Hampton Roads to strengthen the Union naval forces still afloat there.

She had arrived in that strategic roadstead by 14 March and, three days later, was officially transferred to the Navy and assigned to the North Atlantic Blockading Squadron.

While she was being readied for action, the Navy again changed its plans for the vessel and sent her to the western part of the Gulf of Mexico where Flag Officer David Farragut was preparing for his daring attack on New Orleans, Louisiana.

On 10 March 1863, in company with Norwich, Uncas escorted Army transports up the St. John's River with troops who landed and occupied Jacksonville, Florida.

The vessel's deteriorated condition upon arrival prompted further orders on 4 July 1863 directing Uncas to proceed to the New York Navy Yard.