cribbing and bombe management than they get under the normal arrangement whereby we decide what to run and who shall run it".
This paragraph is significant for 3 reasons:
i. It indicates the end of the great Shark battle. From now onwards there were always enough cribs and enough bombes to keep the situation under control.
ii. It raises the problem of what to do with the bombes when Shark was broken, and its solution in using them for 3 wheel keys. On a 3 wheel job a 4 wheel bombe can manage a much shorter crib than a 3 wheeler and thus it became possible for Hut 6, and to a certain extent ourselves, to break keys on which no long cribs were available. In 1944 this 'delayed hop' method of running was to become really vital to Hut 6.
iii. It mentions the existence of Op-20-G and the American bombes to which I have not hitherto referred but which must now be dealt with at some length.
Before attempting to assess the value of the contribution of Op-20-G, which was immense, and also the difficulties which arose, which were fairly numerous, it is essential to understand that they were very different from ourselves in their fundamental organization. They were second in the field and agreed, and kept to the agreement, to play second fiddle and so naturally the people they put into their German machine cryptography were not the best cryptographers they had, but rather efficient and intelligent organizers with cryptographic knowledge. Also most of them started at a time when every member of Hut 8 had at least 2 years invaluable and varied experience of machine cryptography and doubtless mistakes they made were only the same mistakes as we ourselves had been making 2 years before. Their organization, and its machinery was created for the special problem of Shark and was staffed with Naval personnel; there existed no cooperation between the services comparable to that existing between ourselves, Hut 6, Naval Section and Hut 3 and they had not the knowledge of or the dealings with other machine keys which we had over here; it was therefore natural, however regrettable, that they should tend to be narrow minded and to regard Shark as the only really important thing in life. This attitude let it be said at once, was rapidly thrown over by such people as Commander Engstrom, Lt. Commander Church, and the series of U.S.N. liaison officers in this Section and we could be sure at all times of their cooperation in any scheme calculated to increase the return to be got from the bombes.