The pool agreement between the two navigation companies continued through the 1930s and into the 1940s. The S.S. "Manitou" served on the Tobermory ferry route from 1937 until 1941 when it was retired, being replaced by Dominion Transportation Company's S.S. "Caribou". The S.S. "Manitoulin" carried on its regular scheduled route from Owen Sound along the "Turkey Trail" of the North Channel; but instead of terminating at Mackinac Island, she continued through the Soo Locks and proceeded to Gargatua Harbour, and Michipicoten.