Commodore Barney – an armed, side-wheel ferry – was built in 1859 at New York City as the ferryboat Ethan Allen; purchased by the Navy on 2 October 1861; and commissioned later in the month.

Ordered to take part in the expedition against Port Royal, South Carolina in October 1861, Commodore Barney was badly damaged during a storm en route and had to put into Baltimore, Maryland for repairs.

Commodore Barney cooperated with the Union Army in defending Suffolk, Virginia from 11 April – 4 May 1862 and on the Pamunkey River expedition from 24 to 29 June 1863.

From 4–7 August 1863, she took part in the expedition up the James River during which a torpedo (mine) exploded under her bow causing damage to her engine.

After spending the period from 22 April-27 June in the North Carolina sounds she returned to cruise the James and Appomattox Rivers until ordered to Washington Navy Yard on 5 May 1865.