Class: Mackinaw Class Icebreaker

Commisioned: 20 Dec 1944

At: Toledo Shipbuilding Co.

Length: 290 feet

Beam: 74.5 feet

Draft: 19 feet

Displacement: 5,252.4 tons


Icebreaker Mackinaw Maritime Museum

131 South Huron Street

Post Office Box 39

Mackinaw City, MI 49701-0039

Tel: (231) 436-9825

Fax: (231) 436-9826


Latitude: 45.7796960611, Longitude: -84.7198770531

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The Icebreaker Mackinaw (WAGB-83) was constructed during World War II to facilitate winter shipping to maintain year-round war-time production of steel. Normally the lake ice thaws at the end of April, but Mackinaw opened and maintained Great Lakes shipping lanes as early as the third week in March, thus facilitating the early shipping of millions of tons of iron ore and other materials. Usually during the first week in March the Mackinaw would head for the strategic area of the Straits of Mackinac to begin ice operations. As conditions would permit she would work up through the St. Mary’s River to the Soo Locks, into Whitefish Bay and Lake Superior. Later the icebreaker would work in the lower lakes areas.

She is a variant of the Wind class polar icebreakers. Her design is made longer with a wider beam and shallower draft to allow her to operate in the Great Lakes. Mackinaw was built to be literally land-locked, her size not permitting her to leave the Great Lakes.

A diesel electric power plant delivers 10,000 h.p. through twin screws in the stern and one in the bow. The bow propeller is employed to suck the water beneath the ice allowing the Maierform bow to break the ice. When the Mackinaw drives its great bow onto the ice, the icebreaker is capable of breaking through 4 feet of solid sheet ‘blue’ ice. Mackinaw has also plowed through 37 ft. of ‘windrow’ (broken) ice.

Early in its life Mackinaw was used to handle the heaviest buoys on the lakes with the aid of its two 12-ton cranes, to carry fuel and supplies to light stations, to serve as a training ship, and to assist vessels in distress when necessary. In recent decades she continued to extend the shipping season from late March until mid-January. She also served as a goodwill ambassador for the Coast Guard and a training vessel.

The “Mac”, “Queen of the Great Lakes” as Mackinaw has been known with affection, provided 62 years of outstanding service facilitating commerce in support of the economy of the entire nation. She now resides in Mackinaw City, the community for which she was named.

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