
United States Coast Guard Icebreaker Mackinaw


| The icebreaker Mackinaw (WAGB 83) was born with an important mission: to keep the shipping lanes open on the Great Lakes each winter. The critical raw materials feeding the tool and weapons industries were needed to win World War II. Her keel was laid at the Toledo Shipbuilding Company on 20 March 1943 and she was commissioned exactly 21 months later on 20 December 1944. "Big Mac” is powered by six, 2-cycle, opposed-piston, 10-cylinder diesel engines with a total of 12,000 horsepower. However, it is not these engines that drive the icebreaker. The diesels generate electricity through six generators that power electric motors that turn the shafts and propellers of the vessel. There are three electric motors: one 3,300 HP at the bow turning a 12’ propeller and two 5,000 HP at the stern turning 14’ propellers. The Mackinaw is destined to remain in the Straits area; she has become a floating museum in Mackinaw City Ship Statistics Launch Date March 4, 1944 Length 290 feet Beam 74 feet 4 inches Power Six Fairbanks Morse 10-cylinder diesel engines with generators Propulsion Two 14-foot stern propellers with electric drive One 12-foot front propeller with electric drive Total shaft horsepower 10,000 Maximum speed 19 Knots (22 miles/hr) Gross Displacement 5,252.4 Tons Side to Side heeling system 112,000 gallons of ballast in 90 seconds Decommissioned June 10, 2006 Current Location Chief Wawatam ferry dock, Mackinaw City, MI |