janeandbobandmore: GREAT LAKES SHIPPING

Commercial shipping is a major economic activity on the five Great Lakes. The lakes were carved out by the last retreating glaciers and cover over 23,000 square miles, 14,000 of which are in Canada. Because of their great size, the lakes behave more like oceans, which demand especially skilled navigation. On both the Canadian and American sides, the lands surrounding the lakes are rich in minerals (copper, iron and limestone) and agricultural products (grains of all sorts). All these raw materials must find their way to market or to manufacturing sites. And thus major amounts of cargo are transported on the boats that ply these northern waters.

In the early 19^th century, wooden sailing vessels of steadily increasing size carried goods through the Great Lakes. These wooden ships were a maximum of 150 feet in length. The steam engine at first supplemented sails, and then, as reliability increased, replaced sails altogether. Stronger iron hulls replaced the wooden hulls and the size of the boats on the Lakes could increase accordingly.

Today, automated, computerized freighters 1000 feet long efficiently ship ore and other raw materials through the lakes. The hulls of these boats are boxier with greater capacity per unit length. For example, the Stewart J. Cort, the first of the thousand foot boats or Lakers has a carrying capacity of 58,000 tons! As few as 19 in crew can operate the thousand foot boat. The Laker usually carries its own loading/unloading boom and ship-long conveyor belts so, at port, these jobs are done automatically. When a Laker cruises by, it goes on and on and on, being more than three times as long as a football field. The critical issue for shipping efficiency is cargo size. And the new Lakers are as large as a boat can be and still navigate the ports and current locks of the Great Lakes.

Other types of boats sail in the Great Lakes as well. An unusual one is an Articulated Tug/Barge (ATB). When the hull of a ship is still serviceable, but the motor and mechanics less so, a new hybrid can be formed. Engineers remove the boilers and propellers, seal the ship while framing a spot in the rear for a push tug to fit right in. Thus, the original boat is transformed into a barge without any means of propulsion. The push tug is designed with a tall bridge so it can propel the barge from the rear while the captain has a clear view of the waterway ahead.

Another novel Great Lakes vessel has been created when an older boat is removed from service. The original bow and stern is severed, saved and re-attached to a new, elongated middle section to grow the size of the boat. American ingenuity.

Other boats to be seen – private sail and motor boats, Coast Guard cutters, passenger ferries, and small ice breakers. With highly accurate GPS determinations, these boats can replace navigational buoys in exactly the same place from which they had been removed during the previous winter when Great Lakes shipping stops because of ice.

To us, the most interesting vessels are the very few cruise boats* taking passengers through the Great Lakes. Living aboard the boat and traveling day to day, you can experience the natural beauty and historic significance of the Great Lakes and surrounding shores firsthand.