The Unseen Path

For thousands of years, humans have shipped goods across the seas and oceans, and for much of that time the process has been cumbersome and labor intensive. Ships would spend days and weeks in port while dockworkers loaded or unloaded cargo. Accidents and injuries were commonplace. Loss, theft and dockworker strikes threatened owners’ profits.

The man typically credited with changing it all was Malcolm McLean, whose ships carried cargo-laden truck trailers between Northern and Southern ports in the United States. But it was mechanical engineer Keith Tantlinger who turned McLean’s vision into a reality.

Among his most ingenious inventions was the twist lock, which made it possible to stack shipping containers many layers high. He designed a set of steel fittings, which were welded to each corner of a container. Each fitting contained a hole into which the twist-lock could be dropped. A second container could then be stacked atop the first, a handle turned, and the two locked together. The process could be repeated, building a tall stack. Cranes could latch directly onto these corner fittings, neatly lifting containers on and off ships. The twist-lock could also be used to secure a container to a truck chassis or a railroad car.

That single product revolutionized shipping. Today, nearly 90 percent of what we consume is transported by ship. In 2011, the 360 commercial ports in the US took in international goods worth $1.73 trillion — 80 times the value of all U.S. trade in 1960. We have Keith Tantlinger to thank for much of that.