Starting with the "Wenonah", Ojibwa for first daughter, in 1866 Cockburn pressed the government to open the entire Muskoka lake system to navigation by installing locks in Port Carling and opening a cut between Lake Rosseau and Lake Joseph at Port Sanfield. The government was eager to reinforce development in light of the faltering agricultural plan, and built the locks in Port Carling in 1871. Now Cockburn's steamers had access to the entire lake system. Through the years he added more ships and when he died in 1905, his Muskoka Navigation Company was the largest of its kind in Canada. , built in 1887 as "Nipissing", is still in service as at 2019.