In the Great Lakes, Coast Guard icebreakers keep ships, steel industry moving
March 2013 - Last summer, the History show “Great Lake Warriors” debuted, following the demanding lives of grizzled tugboat operators working in brutal winter waters. They push and pull vessels in confined waters, master their harbors and propel barges around the lakes.
But there’s another essential duty to Great Lakes shipping: breaking ice. Although it’s an unsexy and fairly anticlimactic task, it’s a crucial part of keeping Great Lakes’ commerce operating.
It’s particularly key for the steel industry. In 2011, U.S. flagged freighters moved just under 20 percent of iron ore’s total annual shipped tonnage between December 16 and April 15, designated as the “icebreaking season,” according to the Great Lakes Maritime Task Force. One virulent winter kept cutters breaking ice in the St. Marys River (connecting Lake Superior to Lake Huron) well into May.
The Toledo, Ohio-based GLMTF is the largest labor management group ever assembled to promote shipping on the Great Lakes—addressing issues like dredging, water levels and icebreaking. Its members include representatives from ArcelorMittal, U.S. Steel, Tata Steel and Severstal.
“Icebreaking is very important to the steel industry. It takes 1.5 tons of iron ore to make a ton of steel,” says Glen Nekvasil, the group’s secretary representing the Lake Carriers’ Association in Cleveland. “Iron ore producers want to minimize their stockpiling costs and even their production as much as possible. The longer the ships can move, the better for everyone.”
While private tugs handle local ports, the U.S. Coast Guard operates nine icebreakers at large around the Great Lakes. Its largest, the 240-foot-long USCGC Mackinaw WLBB-30, is stationed in Cheboygan, Mich., where it can be deployed to any of the lakes easily. Lake Superior perennially has the worst ice conditions, despite Lake Erie’s susceptibility to completely freezing over. Icebreakers are mainly active at the beginning and end of icebreaking season.
Different areas call for specific icebreaking techniques, says lieutenant commander Eric Peace, executive officer of the Mackinaw. In larger sections of water such as the Straits of Mackinac or Lake Erie, the ship uses brute force to plow through ice that forms into large pressure ridges. The Mackinaw can fully penetrate a 10 foot pressure ridge with four rams or less in 30 minutes. It also uses its directional Azipod (rotating propeller) wash to thrust ice away from the bow or stern—an effective method in confined waterways like the Detroit River.
“In almost all cases, a balance of brute force and finesse has the best result,” Peace says, adding that experienced eyes are the best gauge of ice thickness.
Impact on steel
Although most of the steel production on the Great Lakes is concentrated in industrialized areas, ships still need to make their way through miles of water to haul raw material. From about New Year’s Day to late March, the St. Lawrence Seaway is closed, cutting off overseas access. The Soo Locks, which connect Lake Superior to the lower lakes also are closed during the same period. Icebreakers keep the domestic supply chain moving in the critical winter periods just before and after these closures.
For steel producer ArcelorMittal, its Great Lakes region plants rely on ships because it’s the lowest cost and least energy intensive delivery for its iron ore and limestone. The plants run off of stockpiled inventory while the Soo Locks are closed.
“The most important assumption in inventory planning is that shipments can be sustained until the Locks close and can resume when they open,” says Dan Cornillie, manager, marine and raw material logistics at ArcelorMittal’s Indiana Harbor. “Icebreakers are essential assets in converting this assumption into reality in the face of unpredictable season-to-season variability in ice conditions.”
Each route has notorious choke-points. For ore coming down from Lake Superior, they are the St. Marys River and Whitefish Bay. Lake Michigan-bound ore (Burns Harbor and Indiana Harbor) often gets challenged at the Straits of Mackinac, a narrow passage between Lake Michigan and Lake Huron. Wind-driven ice there can create deep ice “windrows,” Cornillie explains.
For ore headed to Lake Erie (Cleveland), the lower rivers, the St. Clair River, Detroit River and the shallow western Lake Erie, freeze quickly. Icebreakers also alleviate spring ice jams that would otherwise flood the low-lying river banks in the St. Clair River and around others flowing into Lake Erie.
When icebreakers take care of choke-points, the ships typically can navigate the rest of the route unassisted, Cornillie says. For example, during the run from Escanaba, Mich., located in the northern corner of Green Bay to Indiana Harbor, only the 30-mile bay portion of the route freezes solid enough for icebreaking.
“Having the right icebreaking capability in the right places at the right times makes the Great Lakes supply chain dependable,” he says.
This year, the Coast Guard is reassigning the USCGC Morro Bay from the East Coast to the Great Lakes to beef up its icebreaking assets. In recent years, Canada has downsized its fleet to two icebreakers, according to the GLMTF. Nevertheless, U.S. and Canadian icebreakers work together to keep commercial traffic moving.MM