Cryptographic History of Work on the German Naval Enigma

Organization and Records of the Crib Room.

14. The crib room consisted of four senior cribsters (the number varied from three to six but it settled down at four, which was the right size) and about six assistants. The cribsters found new cribs and were responsible for all cribs run on the machines i.e. they did all the actual cribbing. The assistants were responsible for keeping up all records of cribs and for clerical work generally.

15. In the period 1941 to June 1943 when depth cribbing was the main form and there was only one key to break very elaborate records were kept. Given a piece of depth even the vaguest information about the possible content of the messages might be of value; knowledge that one of the messages was likely to begin in one of a dozen ways might enable one to fix its beginning with the help of consequences thrown up from another message. Full records were therefore kept of all forms of standard beginnings. These fell into the following categories.

16. (1) Weather. The beginnings of all weather messages were entered up in folders. The arrangement was that weather was sorted out by the Z watch in the normal course of their duties and send to Hut 8; it was then entered and returned by us to Naval Section.

17. (2) Self Help. All cribs other than weather cribs (i.e. request for beacons) were entered in "Self-Help", folders. They were inferior to weather cribs and not as a rule good enough to run on the bombe in their own right but they were very valuable in depth cribbing. One of the crib room girls used to go to Naval Section, read through the traffic and do the entering. In the early days a good deal of the entering was also done by the men (all the seniors were men and the assistants girls) so that there was little chance of cribs being missed. As time went on more and more of the entering was done by the girls but the traffic was always read by the men at fairly frequent intervals.

18. (3) R.E's. In the early days R.E's were from R.H.V., Werft and


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