In 1955, former trucking company owner Malcom McLean worked with engineer Keith Tantlinger to develop the modern intermodal container. The challenge was to design a shipping container that could efficiently be loaded onto ships and would hold securely on long sea voyages. The result was a tall by wide box in -long units constructed from thick corrugated steel. The design incorporated a twistlock mechanism atop each of the four corners, allowing the container to be easily secured and lifted using cranes. After helping McLean create the successful design, Tantlinger convinced him to give the patented designs to industry; this began international standardization of shipping containers.