"mackinaw"’s design was based on the of coast guard icebreakers, but the cutter was built wider and longer than the other wind-class vessels so that her draft would be shallower. because she was built specially for the great lakes — she was too wide to fit through the pre-1959 saint lawrence seaway — her hull was built lighter than the wind-class vessels, but shared many characteristics, such as a relatively short length in proportion to the great power developed, a cut-away forefoot, rounded bottom, and fore, aft and side heeling tanks. diesel electric machinery was chosen for its controllability and resistance to damage, and she also had a bow propeller. the original blueprints of the mackinaw called for 300 ft in length. she was built with a length of 290 ft.