The 120 machines, the U.S. Navy's Cryptanalytic Bombes, were seven feet high, two feet wide, and ten feet long. Each one weighed 5,000 lbs.
The front and back of the Bombes each had eight columns of four rotors. The top wheel mimicked the Enigma's new fourth rotor while the bottom commutator represented the rightmost, or fastest, rotor of the Enigma. The bottom rotor spun at a speed of approximately 1,725 revolutions per minute, which allowed the machine to complete its run in only twenty minutes.
This information comes from a booklet written by Jennifer Wilcox, Assistant Curator at the National Cryptologic Museum. The text of this booklet is now online.
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Latest update
September 9, 2008