Containerized cargo undoubtedly has been the greatest single advance in marine transportation in the past six decades. In all corners of the world, the ubiquitous container ship is seen, symbolic of the seaborne commerce that carries about 98 percent of all global trade.
Prior to the 1950s, goods primarily were shipped using the traditional “break-bulk” mode. Wire riggings, lines, and assorted booms would be swung out over the dock while large crews of longshoremen moved the goods between ship and shore. Cargo items were loaded on wooden pallets or in slings, with most goods packaged and unpackaged in warehouses next to the dock.
Break-bulk shipping was slow and very labor-intensive. It was not unusual for a vessel to spend several days in port while working cargo. In some cases, labor could represent half the shipping costs. In addition, possibilities for cargo damage and theft were always present.
Wealthy trucking-company owner Malcolm McLean is credited with being the father of modern container shipping. He noted that the real choke point in global shipping was where it changed mode, from land to sea or vice versa. In the mid-1950s McLean proposed that seaborne cargoes be carried in standardized containers similar to trailers used by trucks on highways.
The “container revolution” he proposed would involve the integration and simplification of the way goods moved over the oceans, across the land-sea interface, and overland. His first container shipment was in 1956. A deckload of 58 boxes rode on a World War II–vintage T-2 tanker from New Jersey to Houston, Texas. Ultimately, McLean converted several conventional C-2 freighters and T-2 tankers into “box boats.” In 1960 he formed Sea-Land Service, a company that became a pioneering giant in the new industry. Soon, other shipping companies were converting to containerization in recognition of much lower operating costs and higher profits.
By the late 1960s, however, it was clear that made-for-the-purpose ships would lead to even greater efficiencies. Figuring out how to put boxes on boats was only part of the revolution. In fact, the entire global infrastructure of major seaports would have to be changed. A pier area required a large backshore in which to position containers before and after shipping. Specialized high-speed gantry cranes that could reach across the ships had to be designed, constructed, and installed. Major international investment in new facilities was needed, as few of the old break-bulk terminals could be modified for containerization. The transition took several years.
Another major problem was maritime labor. A transportation system that was faster and more efficient would result in fewer shipboard and longshore jobs. While implementation of containerization was certainly inevitable, international maritime labor had a difficult time adjusting to it. It took more than a decade for containerization to be fully accepted.
Today, more than 6,000 container ships carry 90 percent of the world’s non-bulk (e.g., petroleum, coal, ores, etc.) cargoes. The vessels come in a variety of sizes, from local feeder ships in coastal trades to massive blue-water ships that are the largest afloat. In 2009, box boats moved nearly 466 million containers worldwide; that’s about 1.3 million a day.
The standard unit of ship capacity is the “20-foot equivalent unit” (TEU). Since the most common container is 40 feet long, it is measured as two TEUs. In cost calculations for weight, a loaded TEU is 14 metric tons.
With 600 ships in its fleet, the industry leader is Denmark’s Maersk Line. In 1999, Maersk acquired the Sea-Land company McLean founded (its designation evolved into “Sealand”). Maersk’s newest fleet-members, eight PS-class vessels, are the largest merchant ships in the world, each capable of carrying 15,500 TEUs at speeds up to 25 knots. These 171,000-gross-tonnage vessels are each 1,302 feet long, longer than the U.S. Navy’s Nimitz-class aircraft carriers (1,092 feet). A PS-class behemoth is powered by a single 14-cylinder, 109,000-horsepower diesel engine—the most powerful ship engine ever built.
Recently, Maersk contracted for construction of ten larger ships that each will carry 18,000 TEUs. The first should be in service in 2013, and there is an option for 20 additional ships. The company calls this new variant the “Triple-E class,” for “energy-efficient,” “economy of scale,” and “environmentally improved.”
From McLean’s 58 boxes in 1956 to Maersk’s 18,000 in 2013, the evolution of container shipping has forced significant advances in naval architecture and marine engineering. Ships today are unloaded in hours instead of days, and the largest of them can carry as much cargo as 17 of McLean’s original C-2 ships. Economies of scale are enormous: The largest ships achieve significantly lower unit costs for moving a TEU while boasting increased fuel savings due to improved designs. They also are “green” giants, with greatly reduced stack emissions.