The 2013 Great Lakes shipping season began on March 2 with the sailing of the tug/barge Prentiss Brown/St. Marys Conquest. The vessel, operated by Port City Marine Services, departed its winter lay-up berth in Milwaukee and sailed for Charlevoix, Mich., where it loaded 9,200 tons of cement for delivery to Chicago.

Next to get underway was the tug/barge Dorothy Ann/Pathfinder. The vessel, one of 10 operated by The Interlake Steamship Co., loaded about 13,000 tons of iron ore at Cleveland Bulk Terminal in Cleveland on March 4 for delivery to the steel mill at the end of the deep-draft section of the Cuyahoga River.

During the next several weeks, 52 more U.S.-flag lakers will return to service and spend 10-plus months hauling the raw materials that are the foundation of the industrial heartland, primarily iron ore, limestone, and coal. During the course of the season, more than 1,600 American mariners will crew these vessels.

The U.S.-flag Great Lakes fleet is unique in the world in that virtually every vessel is a self-unloader, which means the ship or barge can discharge cargo without any assistance from shoreside personnel or equipment. The largest vessels can unload 70,000 tons of cargo in 12 hours or less. Prior to self-unloading, it would have taken days to empty a vessel of a cargo that size.

The self-unloading vessel was invented and perfected on the Great Lakes and is one reason waterborne commerce on the Inland Seas is so efficient. A recent study by the U.S. Maritime Administration states that “on average, transportation cost savings from $10 to more than $20 per ton are associated with the use of lakers compared to the next most competitive transportation mode.”

The U.S. Army Corps of Engineers estimates that Great Lakes shipping annually saves its customers $3.6 billion compared to the next least costly mode of transportation.

By law — the Jones Act — U.S.-flag lakers are built in the United States, crewed by American citizens, and owned by American corporations. This holds the vessels to the world’s highest safety and operational standards and mandates that crews pass demanding U.S. Coast Guard exams.

The environment benefits when the Lakes fleet returns to service. Vessels use less fuel to move a ton of cargo than trains or trucks and produce significantly fewer emissions in the process. A number of lakers have been repowered in recent years with state-of-the-art engines and generators that have further reduced the industry’s carbon footprint.