the list of ships owned and operated by pickands mather consists of barges and freighters operating on the great lakes in the united states and canada. vessels include those owned by the marine department of pickands mather & company from the company's founding in 1883 until its sale to diamond shamrock corporation in 1968; those owned by diamond shamrock corporation until the sale of the subsidiary to moore-mccormack resources in 1973; those owned by moore-mccormack resources until the sale of the pickands mather subsidiary to cleveland-cliffs inc. in 1986; and those owned by cleveland-cliffs until the spinoff of the interlake steamship company subsidiary in 1987.