The opening of the St. Lawrence Seaway in 1959 gave rise to an increase in the upstream movement of iron ore from the lower St. Lawrence to Lakes Ontario, Erie and Michigan and in the downstream movement of Canadian and American export grain from Lakehead to lower St. Lawrence transhipment terminals. A new generation of “Great Lakes” bulk carriers was conceived so as to maximise the cargo lift on Seaway dimensions. Between 1960 and 1965, Papachristidis ordered six of the maximum size 26,000 deadweight ton “lakers” in Canada, and, through imaginative financing and aggressive pricing, was able to break into this closed domestic trade with his modern fleet of Canadian-flag vessels. The Papachristidis Great Lakes fleet operated successfully parallel to the deep-sea fleet during the next decade and extended the Canadian-flag activities at a time when Canadian operators could no longer compete in international trades under the domestic register. In 1972, an uncertain future in Great Lakes shipping induced Papachristidis to sell the laker fleet, thereby disposing of the last Canadian-flag vessels the Group was to own.