8. The Liberty ships were an early example of planned obsolescence
The design of the Liberty ships provided vessels which offered a service life of approximately five years, long enough to meet the emergency contingencies of the Second World War. In practice, some remained in service long after the war. Private shipping companies purchased many ships post-war, including many Greek shipping magnates for use in the Mediterranean. Aristotle Onassis was one such shipping titan. The majority though did not last much longer than their design life, at least not in actual use. Most sat in reserve fleets awaiting purchase by a ship breaker for scrap value. The biggest problem they presented to potential operators was the extensive maintenance required to keep them in operation. Another problem was their slow speed, around 11 knots. Post-war shipping required faster speeds to be competitive.
They were also of limited use in the colder waters of the globe. During the war, several Liberty ships presented problems with cracking of their hulls. Over 1,500 Liberty ships required repairs for hull cracks during the war. Three ships cracked so severely they broke in half and sank, with loss of life. Maritime Commission officials blamed the shipyards for shoddy construction. Britain’s Ministry of War concluded the cracking, which occurred on other welded ships but not riveted vessels, was due to the brittle nature of the steel. In cold waters, such as those in the North Atlantic, the temperature grew so low the steel lost its ductile state, becoming more brittle, and failed along the stress lines of the welds. The practice of overloading the hulls added to the problem, though it continued throughout the war.