They were all spy-conscious in Washington now, but such anecdotes apart, the central event of Alan's visit was the breakthrough back into the U-boat Enigma.
现在的华盛顿人都有防范间谍的意识，但这只是个小逸闻，艾伦来访的重要任务，是关于潜艇谜机。
This was achieved without the possession of faster Bombes; it depended upon a precarious thread of luck, ingenuity, and a German blunder.
在更高速的炸弹机出现之前，这种谜机就已经被破解了，这是依靠一系列的运气和创造力，还有德国的失误。
It went back to the weather signals that in mid-1941 had given them an almost unfairly simple crib each day, thanks to the fact that they were transmitted both in the Enigma, and in the special meteorological cipher.
此事要从1941年中期的气象信号说起，这些信号是用谜机和一种特殊的气象密码同时发送的，所以每天都能给布莱切利提供便捷而清晰的"床位"。
But early in 1942 a change in the system had denied this method to Hut 8. Not until the U-boat capture of 30 October could it be regained.
但在1942年初期，这个系统发生了一点改变，于是8号营房的这个方法失效了。直到10月30日他们缴获了一艘潜艇，才重新有办法取得床位。
This gave them the cribs, but the difficulty remained that it would take three weeks to work through all the rotor settings, just for one day's traffic.
但仍然有一个困难是，推导一天的盘位需要三个星期。
Here, however, they were saved by a German blunder which, in effect, threw away all the advantage that the fourth wheel offered.
然而，德国的一次愚蠢的失误再次拯救了他们，这次失误使第四轮盘的优势完全泡汤。
For the weather reports, and other routine short signals, the U-boats used their Enigma with the fourth wheel in 'neutral' position, thus reducing the cryptanalysts' problem to the one they had mastered in 1941.
U型潜艇在发送气象报告和一些例行信号时，只使用了三个转盘，这就使问题变成了布莱切利在1941年就已经解决的老问题。
This in itself was not fatal for Germany; the greater mistake lay in the fact that the three rotor settings used for the weather reports were also used for all the other traffic of the day.
对德国来说，这本身不是致命的，更严重的错误在于，当他们使用四个转盘发送其它通信时，前三个转盘的盘位设定仍然不变。
For this the analysts now needed only to work through 26 possibilities for the fourth wheel, rather than the 26 × 336 × 17576 possibilities that would otherwise have been the case.
因此，分析人员只需要检查第四转盘的26种盘位，而不是本来应该需要检查的26×336×17576种。
As a result of this slip, Hut 8 was able to supply decrypted messages from 13 December.
这个失误的结果是，8号营房从12月13日开始，又能正常工作了。
They had weeks in which nothing worked out.
他们已经好几个星期没有产出信息了，
But it was sufficiently copious a flow of information for the Tracking Room in the OIC to have by 21 December a clear idea of the location of all eighty-four U-boats at large in the North Atlantic.
但到了12月21日，他们可以清楚地获知北大西洋全部84艘潜艇的方位，这对于作战情报中心的追踪室来说，已是一桌足够丰盛的大餐了。
And this time Hut 8 was not alone. In Washington, Alan Turing was indoctrinating the American analysts into all their methods.
8号营房这次不是独自战斗，艾伦·图灵正在华盛顿，把所有的方法教给美国分析人员。
Now, when the rotor settings were discovered, they were passed back and forth across the Atlantic, the analysts beginning to communicate directly as indeed the two tracking rooms were also doing.
现在，双方破解出来的盘位设定在大西洋上空传递着，两国的分析人员展开了密切合作，双方的追踪室亦是如此。