From the Civil War Forum.
Even though the U.S. West Coast was far from the major fighting, there was still the possibility of Confederate commerce raiders attacking or attack from Southern sympathizers from Canada. A small fleet maintained guard along the Pacific coast.
The Pacific Squadron 1861-1865: Six sloops-of war:
USS Lancaster-- flagship
Also, at end of the war, the USS Suwanee.
The Saranac was commanded at one time by Gustavus H. Scott.