Naval Security Group WAVES and the BOMBES
In 1943, a large contingent of WAVES were sent to Dayton, Ohio where they attended Sugar Camp. Some went directly there from Boot Camp, others were sent there from Naval Communications Annex (OP-20-G), on Nebraska Avenue in Washington D.C.
Sugar Camp was named for a grove of maple trees tapped for maple sugar sap. The National Cash Register Company (NCR) had used Sugar Camp as the location for a training school for salesmen and opened it to the Navy in 1943. Sugar Camp encompassed 31 acres containing 60 residential cottages, a dining hall, classrooms, a recreation building, a social center, a large auditorium and an administration building. The Camp was on a raised area of land above the main NCR factory. Part of the daily routine of the 200 WAVES assigned there was to march from the Camp down the hill to the NCR factory where they pursued work and studies relating to the BOMBES machines that were being constructed at the NCR factory. After completing their studies, the WAVES were sent to the Naval Communications Annex (OP-20-G), on Nebraska Avenue in Washington D.C. to operate and provide minor maintenance on the BOMBES machines. By the end of the war there were over 500 WAVES stationed at Nebraska Avenue operating and maintaining the BOMBES machines.
In the fall of 1943, a special building was constructed at Nebraska Avenue to house the Navy’s 100 BOMBES. This building required high capacity air conditioning equipment to remove the heat generated by the numerous motors, clutches, relays and electron tubes inside the BOMBES.
What is a BOMBE?
A BOMBE was a large electro-mechanical machine used to recover the keys used by German ENIGMA cipher machines. This encryption machine was used by the German armed forces and other governmental agencies. The Navy BOMBES were used for key recoveries of German naval four rotor ENIGMA machines. Once key recoveries were made, it was possible to decipher German naval messages including those to and from U-Boats. This work was done in cooperation with the British cryptanalysis at Bletchley Park, England.
Physically, the BOMBES were about 6 or 7 feet tall, 10 feet wide, and 2 or 3 feet deep, weighed 5,000 pounds, and were mounted on large rollers. On their gray metal faces were two rows of black disks marked 00 to 25 around their circumference with a rotatable brass pointer. Below, there were four rows of eight wheels each. The WAVES who operated the BOMBES were given a Top Secret (ULTRA) clearance. The cryptanalytic operations were highly compartmentalized and most BOMBE WAVES were not told exactly what they were doing; however, they soon were able to what their very important work was about.
To insure the machines were in properly operating, two WAVES were assigned to work on the sets of four machines to make “machine checks” before and after each operational “run.” If a problem was indicated by a machine check, the WAVE operator would make out a trouble report for the male maintenance watch chief. Maintenance work was then performed by the men. Some WAVES on their own learned to repair circuit boxes located on the sides of the BOMBES.
Operating the BOMBE
Operational menu for setting up a BOMBE were typed by WAVES in the cryptanalytic section and were forwarded to a BOMBE supervisor by pneumatic tube. After the Bombe completed a run, a WAVE supervisor checked the printed results on the M-9 Bombe checker. The supervisor then gave the menu to a BOMBE operator. The menu consisted of instruction to set up th
e BOMBE wheels, where to place the rotors, and whether a short or long rune was desired. The short run took ten or fifteen minutes. After setting up, the BOMBE was turned on and it would run until a “hit” occurred. The “hit” indicated that an electrical pathway had been found. The BOMBE was running too fast to mechanically record a “hit,” so this was done by an electronic memory circuit. When the machine recorded a “hit,” a brake was automatically applied to stop the drive shaft. A clutch and rewind motor were then engaged to reserve direction until the drive shaft was stopped on the correct “hit” position as indicated by the memory circuit. The rewind effort took only ten to fifteen seconds. While the BOMBE was operating, it would make ticking sound like a clock. It was this ticking sound that gave the machine the name
From Encryption to Plaintext
If no “hit” were recorded, the BOMBE would complete its run in 10 to 15 minutes. The resultant “hit” information was recorded by a printer identifying the correct rotor position. The WAVE operators would pass this information through a small door to another supervisor’s room. These recovered keys on the printout were sent back to the cryptanalytic unit by the BOMBE supervisor via pneumatic tube. After the key recovery was confirmed by a cryptanalyst, a WAVE typed out the Germen U-Boat intercepted messages on ENIGMA machine analogues which then produced German plain text.
The plain text was in a continuous stream of German without spaces between words. A Yeoman carried these sheets of paper upstairs to the translator’s office and dropped them into a wire basket. The translators divided the strings of letters into words and translated them into English. Several of the translators were WAVES. One was LT Erminnie Bartelmez, USNR, who had a doctorate in German and LT Marjorie Boynton, USNR. Yeomen, including some WAVES, typed up the handwritten translation and carried them to the watch officers who brought them to the intelligence section. The time between the interception and reporting of decrypted U-Boat messages was eventually measured in hours rather than days.
Many historians believe the work the WAVES and other code-breakers did significantly shortened the war in the Atlantic and the Pacific by more than three years.
Upon being honorably discharged, the WAVES received the Naval Unit Commendation meal. Also, they were entitled to the American Theatre and World War II Victory Medals. Many received special letters of commendation from the officers they worked with praising their performances. Later, a letter was sent to all WAVES who served until VJ day, to their home addresses, from Secretary of the Navy, James Forrestal.
The following former WAVE BOMBE operators are credited in the preparation for the three posts:
Bessie M (LeBlanc) Jacobsen
Betty Huddleston Arndt
Dorothy Mae Smith Hatcher
Mae L. Howard
Edith Plumly Simpson
Elezabeth Howard Thomas
Edited by Mario Vulcano