As a youngster, I often visited Lock & Dam 24 in Clarksville, Missouri, to watch the low-slung hopper barges loaded with Midwestern grain travel through the locks with the help of towboats. Contrary to their name, the towboats gently push — rather than pull — the barges into the lock, a 110-foot-wide and 600-foot-long concrete chamber built between the riverbank and the dam. Locks, along with dams, create a step-like system that helps vessels navigate the changing elevations of the river.
There are many types of barges: A dredging barge is basically a clamshell bucket excavator on a floating platform. In China’s Grand Canal, self-propelled barges sport a cabin and motor at the back. Decades ago, sail-powered Thames barges plied England’s coasts and rivers. Barges are even used as ocean-going landing pads for SpaceX’s Falcon 9 rockets.
But the hopper barge that has become integral to the modern food system, especially in the United States, is a 200-foot-long, 35-foot-wide, 13-foot-deep boat with a large fiberglass cover. These barges are perfect for transporting bulk, dry cargo like grain or coal. They have no engines. Instead, they are designed to be lashed together with a web of steel cables into groups of two to 70 barges, known as tows, and pushed by a single towboat.
Towboats vary in size depending on how many barges they will be pushing and how and where they will be operating. Most are diesel-fueled and include a pilothouse that rises three to four stories above the deck, a kitchen, and quarters that house a crew of eight to 10 people. The average crew includes a captain and a pilot who alternate six-hour shifts in the pilothouse, a cook, a mate, four deckhands and an engineer. Crews serve 28-day stints, usually taking a four-week break before returning to the river.
LOCK AND LOAD
Hopper barges haul corn, soy, wheat, fertilizer and other bulk dry goods, primarily on the Mississippi, Ohio and Illinois Rivers. But they don’t travel alone. The standard tow on the Upper Mississippi is 15 barges, or five rows of three barges abreast, a bundled mass of vehicles that’s too long to go through the lock at one time.
The solution? Unbundle. Once in the lock, the first three rows of barges are disconnected. After the gates close on a southbound tow, the emptying valve under the lock opens. The water and thousands of tons of metal and cargo descend 15 feet. The process repeats for the towboat and remaining barges.
Each of those 15 barges can carry between 1,500 and 1,750 tons of dry cargo — enough wheat to bake 2.5 million loaves of bread, or one loaf for every person in Houston. A standard 15-barge tow can haul enough wheat to fill 240 railcars or 1,050 trucks, enough to provide a loaf of bread for every resident of New York, New Jersey and Virginia combined. But the wheat on the barges steaming down the Mississippi is likely bound for Europe or Asia, rather than New York.