USCGC Mackinaw (WAGB-83) is a decommissioned United States Coast Guard icebreaker which operated on the Great Lakes for 62 years. A state-of-the-art icebreaker when she was launched in 1944, Mackinaw was built to extend the shipping season on the Great Lakes into the winter months and thereby strengthen the wartime economy of the United States during World War II. Unlike the U.S. Coast Guard's large icebreakers before and since, Mackinaw was designed specifically for use in the shallow, freshwater Great Lakes.
Mackinaw was homeported in Cheboygan, Michigan for her entire Coast Guard career, travelling as needed into Lakes Superior, Huron, Michigan and Erie during icebreaking season to keep shipping lanes and harbors open. After her decommissioning in 2006 in the face of high operating costs, she sailed to a permanent berth in Mackinaw City, Michigan to become the Icebreaker Mackinaw Maritime Museum.
The decommissioned Mackinaw was immediately replaced by a smaller multipurpose Coast Guard cutter, also named Mackinaw (USCGC Mackinaw (WLBB-30)) and also homeported in Cheboygan.
Construction In the fall of 1941, the United States briefly borrowed the Soviet icebreaker Krassin. Although attempts to lease the icebreaker from the USSR for a year fell through, she was studied by the Coast Guard and her design influenced that of the Coast Guard icebreakers, including Mackinaw, constructed at that time. Another influence was Lieutenant Commander Edward Thiele, USCG, who travelled to Europe on vacation just before the United States entered the war and informed himself of modern icebreaker designs, particularly that of the state-of-the-art Swedish Ymer. Finally, the icebreaking features of Great Lakes rail ferries which operated in heavy ice in the Straits of Mackinac were studied. The resulting preliminary design of the Mackinaw was by the Coast Guard Naval Engineering Division and the final design by naval architects Gibbs & Cox of New York. Gibbs & Cox set up a special icebreaker design section for the Mackinaw and the Wind class of icebreakers.
After her construction was authorized on December 17, 1941, the Mackinaw was laid down on March 20, 1943, at Toledo Shipbuilding Company in Toledo, Ohio. The Toledo Shipbuilding Company was unprepared to undertake a shipbuilding project this large and complex and when the ship remained incomplete more than two years after the company took on the project, the Toledo Shipbuilding Company went bankrupt due to penalties levied for the delayed construction. The American Ship Building Company took over and Mackinaw was side-launched on March 4, 1944, and commissioned on December 20, 1944 under the command of Commander Edwin J. Roland. Due to war efforts Toledo area male workers were at an all-time low. The shipyard opened their hiring to Toledo area women. Mackinaws eventual cost was $10 million, a substantial overrun of her projected cost of $8M and a very high cost for a ship of that era.
Mackinaws design is based on the Wind class of icebreakers, but she is built specifically for use on the Great Lakes. She was built longer and wider than the ocean-going Wind-class vessels so that she would draw less water in the comparatively shallow water of the Great Lakes. The cooling system which circulates fresh water through her diesel engines draws directly from the water surrounding the ship. She is constructed of mild steel rather than the high-tensile steel of the Wind class.
However, Mackinaw'''s design shares many characteristics with that of the Wind-class icebreakers, such as a relatively short length in proportion to the great engine 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. Although the original blueprints of the Mackinaw called for a length of , in the event she was built with a length of .
The Mackinaw's double hull is very strong. The frames between the two hulls are spaced about 16 inches apart and form a truss. Voids between the inner and outer hull are filled with fuel tanks and ballast tanks. Water can be pumped rapidly into and out of the ballast tanks (160 tons in 90 seconds) so that the ship heels from side to side through an arc of 24 degrees; this pushes ice away from the sides of the ship. The ballast tanks can also be used to trim the ship fore and aft.
As well as her twin stern propellers, Mackinaw also has a bow propeller, which pulled water from underneath the ice ahead of the ship; when the Mackinaw rode her bow up onto the ice using her cut-away forefoot, the unsupported ice broke apart under the ship's weight into the hollow space underneath. The turbulent wash from the bow propeller also helped the hull slide through the ice around it. Mackinaw could break through up to of solid "blue" ice and up to of shattered, heaped-up "windrow" ice. The sides of her hull are protected by an "ice belt" of steel plating up to several feet above her waterline, while her bottom is armored with steel.
Each of the three propellers has its own Westinghouse DC electric motor. The motor driving the bow propeller is capable of and those driving the stern propellers can produce each. These motors are driven by six diesel generator sets, each set comprising a Fairbanks-Morse 38D8-1/8 diesel engine and an accompanying electrical generator. The electrical output of the six generator sets can be switched to the three electric motors in different combinations. When breaking ice, two generators can be assigned to each of the two aft propellers and two generators to the bow propeller. When cruising in open water, each of Mackinaws aft propellers can be driven by one, two or three generators.
For ground tackle Mackinaw shipped two stockless bower anchors, each with of chain composed of links. Until they were removed in 1982, two twelve-ton cranes on the fantail could be used to handle seaplanes or buoys. Mackinaw was also equipped to supply fuel oil to remote lighthouses.
Service history
The Mackinaw was constructed to extend the shipping season on the Great Lakes during World War II. Ice formation on the Lakes caused the shipping season to end in late December, not able to reopen until the ice melted in late March or early April. Prior to the war, the light icebreakers USCGC Escanaba and USCGC Tahoma had worked to keep the shipping lanes open in winter, but once the U.S. entered the war these two cutters were reassigned to the north Atlantic. The Coast Guard calculated that extending the shipping season by ten days in winter would allow the delivery of an additional three and a half million tons of iron ore, coal and limestone to the steel industry, or alternatively of 120 million bushels of grain to food markets.
1945-1960
The Mackinaws first assignment after she was launched in the final winter of World War II was to train 25 Soviet sailors from January 20 to February 6, 1945, before the sailors took up engineering duties on a lend-lease Wind class icebreaker. After the war ended Mackinaw continued on icebreaking duty in the Great Lakes; at that time, the channels between the Great Lakes and the open ocean were not yet large enough to accommodate her. The Mackinaw was then the largest member of a collection of icebreaking Coast Guard cutters on the Great Lakes which also included 180-foot buoy tenders and 110-foot tugboats. During the late 1970s and through the 1980s the latter were replaced by 140-foot Bay-class tugboats. Starting in 1968 and continuing until the last was decommissioned in 1989, one or another of the Coast Guard's Wind-class icebreakers would help out in winter. The Mackinaw and these other Coast Guard icebreakers provided safe passage for freighters as they delivered their cargo of taconite, grain, and other resources around the Great Lakes to ports such as Detroit, Chicago, and Gary.Mackinaws icebreaking season each year depended on that winter's ice accumulation on the Great Lakes but typically lasted about 70 days. The season generally began in mid-December and continued until warming weather in spring melted the lake ice, which might be as late as May. A month-long "Charlie period" starting in mid-February took the ship out of service for recovery by both ship and crew from the round-the-clock stresses of icebreaking.
During the icebreaking season the Mackinaw maintained shipping lanes through the ice in Whitefish Bay at the eastern end of Lake Superior, along the St. Marys River connecting Lakes Superior and Huron, and through the Straits of Mackinac connecting Lakes Huron and Michigan. She occasionally cleared ice on the Detroit and St. Clair rivers connecting Lakes Huron and Erie. In very severe winters she visited icebound ports on the lower Great Lakes as far away as Buffalo on eastern Lake Erie. Wherever she went, Mackinaw broke the ice around any trapped ships that she encountered and escorted them to open water.
In the spring of 1947, the Mackinaw and the USCGC Tupelo opened ice-clogged Buffalo harbor. Working from May 9 to 14, they freed 38 ships trapped in ice outside the harbor and escorted them in, and freed 49 ships trapped inside the harbor and led them out. Mackinaw returned the next spring with the USCGC Acacia and during March 17 and 18 broke a passage into the ice-locked harbor which allowed 12 ships to leave. This was the earliest known date in over 50 years that ships had been able to leave Buffalo Harbor in the spring.Mackinaw returned to Buffalo again in April 1961 to lead Tupelo and the Coast Guard tugboats USCGC Kaw and Ojibwa in escorting vessels in and out of the ice-clogged harbor.
The Mackinaw did not routinely perform search and rescue missions; these were normally carried out by smaller, faster, nimbler Coast Guard cutters, boats and aircraft. The Mackinaws first large search and rescue mission was not until the disappearance of Northwest Orient Airlines Flight 2501 over Lake Michigan on the night of 23 June 1950. Mackinaw, along with other Coast Guard and Navy ships and state police forces, fruitlessly searched for survivors and instead collected airplane debris and human body parts from a wide swath of Lake Michigan. "It was horrible," said David Kaplan, a boatswain's mate on the Mackinaw. "We picked up 32 buckets of remains and stored them in the walk-in cooler until the medical examiner came and took them. We found a lady's purse that looked intact until we opened it. The glass in the small make-up mirror was pulverized."Mackinaws powerful engines made her useful for towing large vessels in distress, starting when she towed the U.S. Navy minesweeper USS Elusive into Detroit in late February 1945. Mackinaw had been escorting Elusive through the ice from Lorain to Chicago when the minesweeper's propeller was damaged by ice in Lake Erie.
On November 21, 1956 the 7,300-ton grain carrier J. P. Wells was caught in a storm packing 65 mph winds on Lake Superior. Her rudder was damaged and the freighter began sailing in circles. The Mackinaw cancelled plans to invite the families of the crew to a Thanksgiving dinner onboard and sailed to assist the freighter. Mackinaw, accompanied by the USCGC Mesquite, towed the J. P. Wells to Whiskey Bay in Lake Superior, 15 miles north of the Soo Locks, where the freighter anchored waiting for a commercial tug to tow her to Sault Ste. Marie for repairs. Thanksgiving was celebrated underway.
During the construction of the Mackinac Bridge from 1954 to 1957, the Mackinaw would clear away ice floes piling up against the massive caissons surrounding the bridge piers being constructed. This allowed the foundations of the bridge to settle into place undisturbed during the winter. The icebreaker would work all day around the caissons for several days at a time, anchoring nearby at night and resuming work the next morning.
1960-1990