The idea of an intermodal container first came to the mind of Malcolm Purcell McLean. In 1937, he developed the “big box” concept while he waited most of the day to deliver cotton bales on his truck to a pier in New Jersey, USA. The concept revolutionized cargo handling worldwide ever since.

“Suddenly it occurred to me: Would it not be great if my trailer could simply be lifted up and placed on the ship without its contents being touched?”, he recalled later.

The subsequent development of containerized shipping in the 1950s and 1960s was largely based on McLean’s initial dream. 

Boxes similar to modern containers of our day had already been used in rail transportation. What was added by the revolutionary ideas of McLean was his belief that efficiency could be highly improved through intermodal containers and his perseverance in making it happen.

McLean converted the World War II tanker Potrero Hills to a box ship capable of carrying containers and rechristened her the Ideal X. She made her maiden voyage on April 26, 1956, sailing from Newark to Houston carrying 58 metal containers and 15,000 tons of petroleum. When the ship had been unloaded in Houston port, McLean’s company was already taking orders to ship goods back to Port Newark in containers.

SS Ideal X 
(Source: The geography of transport systems)

“Loading loose cargo on a medium-sized cargo ship cost $5.83 per tonne in 1956. McLean’s experts calculated that the cost of loading the Ideal X at 15.7 cents per tonne. With numbers like that, the container seemed to have a future.”

McLean went on to becoming a ship owner with his company Sea-Land. Initially the containers were loaded on their chassis, but later the chassis was left behind, enabling containers to be stacked on top of each other.

UP: Ideal X with the world’s first load of containers
Source: http://www.worldtrademag.com

DOWN: A modern container being loaded by a gantry crane.

The first vessel to carry containers only was Sea-Land’s Gateway City which made her maiden voyage on October 4, 1957.

Eventually, ISO standards for containers were published between 1968 and 1970 by the International Maritime Organization.