In 1941, as America entered WWII, the need was critical to massively expand the merchant marine fleet--the mainstay of which was the all-welded Liberty cargo ship. During the next four years, 16 shipyards delivered 2,580 ships--the largest production run ever for a single ship. What's even more amazing is how the efficiency of these shipyard teams continued to increase at over a 40 percent rate each of those years. For example, at the Calship shipyard, the first Liberty ship took 1.73 million labor hours to build. Only three years later, the fastest ship constructed there took only 406,000 labor hours to build--a 426-percent increase in efficiency! This case is often used as a classic illustration of the growing efficiency of teams.