Although not a weapon in the traditional sense of the word, arguably no
item in the Allied arsenal contributed as much to the defeat of the Axis
during WWII as did the Liberty ships. The 2,710 Liberty ships placed
into service between 1941 and 1945 provided a vital link in the supply
chain not only of US but also Allied forces during WWII. Although the
basic design itself was obsolete even before the first one slid down the
builder's ways, it had the advantage of being relatively easy to
produce, and simple to operate and maintain. Thus, the vessels were
mass-produced by no fewer than eighteen shipyards. Building time,
initially 244 days, dropped to forty-two days per ship, although as a
publicity stunt the Robert E. Peary was launched four days and fifteen
and a half hours after the keel was laid.