Order up! One new Mighty Mac to go

The continued reliability of moving cargo on the Great Lakes during the "ice season" took a giant step forward with the launching of the U.S. Coast Guard's new Great Lakes Icebreaker Mackinaw in Marinette, Wis., on April 2. The vessel is expected to enter service this fall and assist the movement of vital raw materials when ice begins to form on the Great Lakes in December.

"Lake Carriers' Association is pleased the Lakes will continue to have a U.S. Coast Guard vessel designed to perform heavy icebreaking when the current Mackinaw is retired next year," said James H. I. Weakley, president of the trade association, which represents U.S.-Flag vessel operators on the Great Lakes.

The Mackinaw is replacing a U.S. Coast Guard icebreaker of the same name that was launched in 1944 and is scheduled for decommissioning in 2006. While still structurally sound, the current Mackinaw is in need of extensive modernization to reduce its operating costs, but its design is such that icebreaking would still be its only function. The new Mackinaw has been designed to perform other Coast Guard missions, such as placement of aids to navigation, search and rescue and homeland security.

The new Mackinaw was authorized by Congress in 1999 following a study to determine icebreaking needs on the Great Lakes. The study concluded that the Lakes must have a heavy icebreaker to assure the movement of cargo during periods of ice cover.

"The Great Lakes delegation in Washington worked tirelessly to gain authorization and appropriations for the new Mackinaw," said Mr. Weakley. "In particular, I want to thank Congressmen Dave Obey (D-Wis.), James L. Oberstar (D-Minn.) and Bart Stupak (D-Mich.) and Senator Mike DeWine (R-Ohio) for their commitment to this project."

The movement of dry-bulk cargos on the Great Lakes generally begins in early March and continues until the end of January. During that period, shipments of iron ore, coal, limestone and other cargoes can top 200 million net tons. During a typical ice season (roughy December 16 to April 15), shipments of certain commodities will equal 15 to 20 percent of the year's total.

The ice that forms on the Great Lakes can be three to four feet thick. Windrows (slabs of broken ice piled atop each other by the wind) can easily reach heights of 10 to 12 feet. Some of the largest commercial vessels working the Great Lakes have ice-strengthened hulls and power plants capable of generating 19,500 horsepower, but they need a vessel designed to perform heavy icebreaking to keep the shipping lanes open.

The Mackinaw's primary responsibility will be the major chokepoints, Whitefish Bay at the eastern end of Lake Superior and the Straits of Mackinac that connect Lake Michigan to Lake Huron.

The vessel will assist commercial navigation in Duluth-Superior when needed. For example, the winter of 1993-94 was so severe that Lake Superior froze over entirely, a rare occurrence. The current Mackinaw led convoys across Lake Superior until April 7, 1994.

Smaller Coast Guard icebreaking buoy tenders work the connecting channels (St. Marys, Detroit and St. Clair Rivers) and approaches to ports and harbors.