Wooden ship Iowa, built St. John, New Brunswick, 1849, 850 tons, 151.5 x 31 x 22.8 ft. Owned White Star Line, Liverpool, then owned by J Steel, Black Star Line, Liverpool. Voyage Liverpool to Australia, departure 2nd May 1854, master Henry Selby. Missing with 85 passengers [from here] . Presumed foundered after spoken on 1 June 1854.

[from Liverpool Mercury - Tuesday 03 January 1854]:
"WHITE STAR" LINE OF AUSTRALIAN PACKETS. Loading Berth, Salthouse Dock. FOR MELBOURNE.
Ships. Tons. Captain. To sail.
TAYLEUR 4000 NOBLE 5th Jan.
IOWA 1800 REED 5th Feb.
BEN NEVIS 2500 HERON To follow.
FOR MELBOURNE, PORT PHILLIP, (Landing Passengers and their Luggage at the Wharf), The magnificent new clipper-ship TAYLEUR, - J. NOBLE, Commander; 2400 tons register; 4000 tons burthen. Landing Passengers at Sydney, Adelaide, and Geelong. This truly splendid vessel, just launched, and the largest merchantman ever built in England, will undoubtedly prove to be the fastest of the Australian fleet, as she has been constructed expressly with the object of attaining the very highest rate of speed. Her vast dimensions enable the owners to provide passenger accommodation not to be met with in any vessel afloat. Through ventilation has been secured, and by means of ports, of which she has one at every seven feet, and numerous skylights, the passenger deck is perfectly lighted in every part. The undersigned have, therefore, no hesitation is affirming that the TAYLEUR presents advantages, as a passenger conveyance, superior to any ship hitherto despatched to the Australian Colonies.
[White Star line advertised new vessel Mermaid, master Samuel Reed, previously master of Iowa, sailing 25 March, 1854]

After change of ownership [from Northern Daily Times - Monday 13 March 1854]:
"BLACK STAR" LINE OF AUSTRALIAN PACKETS FOR MELBOURNE, PORT PHILIP, Landing Passengers and their luggage on the wharf at the ship's expense, The magnificent well-known Clipper, IOWA, 1,500 tons burden, HENRY SELBY, Commander, (who has been engaged for a number of years surveying the coast of Australia.) This beautiful vessel is one of the strongest and fastest sailers in the passenger trade; and the high character of her commander, together with the liberality displayed in the dietary, only require seeing to give her a decided preference. No passengers will be taken between decks, all the berths being fitted in the house on deck, which is exceedingly spacious, running the full length of the ship. Families, of a large or small number, can be accommodated with a state-room to themselves, provided a few days' notice is given, and deposits forwarded. She is A 1 at Lloyd's, newly coppered, and carries a surgeon. No expense will be spared to make her in every way an excellent, safe, and comfortable passenger ship. For further particulars apply to HENRY THOMAS & Co., 44, Dale-street, Liverpool.
[Sailed from Liverpool 2nd May 1854, with master Selby]

[from Daily News (London) - Thursday 06 July 1854]:
Spoken: Iowa, Liverpool for Melboure, June 1, lat 4N, lon 22W.

[from Liverpool Mercury - Tuesday 06 March 1855]:
The Iowa, Selby, which sailed hence for Melbourne, 2nd May, was spoken on the line [equator], 1st June, and has not since been heard of. She had 60 emigrants on board.