The U.S. ship A.Z. was one of a number of vessels belonging to the New York firm of A[ugustus] Zerega & Co. which bore the initials of members of the Zerega family. The other vessels were the J.Z., the L.Z., and the E.Z. The A.Z., almost certainly named after Augustus Zerega, the head of the firm, was built at East Boston, Massachusetts, by Donald McKay, in 1847, and registered at the port of New York on 15 June 1848. 675 tons, 140/144/150 (keel / deck / overall) x 33 1/2 x 20 1/2 ft (length x beam x depth of hold). After an initial voyage on the Regular Line of sailing packets between Boston and New Orleans, the A.Z. became a "one-way emigrant packet", clearing from Liverpool in the Black Star Line, carrying emigrants to New York, and clearing from New York for England in Zerega & Co's Red Z Line, carrying raw materials for British industry. The A.Z. had a short career, foundering on 5 October 1858, on a voyage from New York to Glasgow under the command of Capt. Greenland; the captain and crew were saved.

Sources: William Armstrong Fairburn, Merchant Sail (Center Lovell, Maine: Fairburn Marine Educational Foundation, [1945-1955]), II.1268; IV.2350; V.2949; Carl C. Cutler, Queens of the Western Ocean; The Story of America's Mail and Passenger Sailing Lines (Annapolis: United States Naval Institute, c1961), pp. 384, 386, 456; Forrest R. Holdcamper, comp., List of American-flag Merchant Vessels that received Certificates of Enrollment or Registry at the Port of New York, 1789-1867 (Record Groups 41 and 36), National Archives Publication 68-10, Special Lists 22 (Washington, DC: National Archives and Records Service, 1968), p. 11; New York Herald, 16 November 1858, p. 8e, and 17 November 1858, p. 8d.