The second USS Canonicus was the Southern Pacific freighter El Cid temporarily converted for planting the World War I North Sea Mine Barrage.

Newport News Shipbuilding and Dry Dock Company launched El Cid at Newport News, Virginia on 7 October 1899 for service between New York City and Gulf of Mexico seaports of New Orleans and Galveston, Texas.

She was fitted out for United States Navy service by Morse Dry Dock and Repair Company at Brooklyn, New York.

Stern ports were cut for launching the mines and the rudder quadrant was raised to give adequate clearance.

The main machinery was overhauled and auxiliary machinery was added for the elevators, for heating the berthing spaces, for refrigerated food storage, for additional fresh water distilling capacity, for magazine sprinklers and galley and washroom plumbing, and enlarged electric generators for lighting and radio communications.