The US 6812 Division Bombe Report Eastcote 1944 Page 70

Tony Sale's Codes and Ciphers

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- 57 - TOP SECRET-T

they are requisitioned. Space is also provided in the book for noting when
the items are received.

ATTENDANCE BOOKS.

A book is kept by each watch showing the attendance for every day of

duty in "operations". The entries are made by the watch officer with
explanatory notes for any discrepancies.


GRAPHS OF PERFORMANCE OF MACHINES AND PERSONNEL.

For the Commanding Officer, Major M.H.Stewart, a number of graphs

were kept to show the performance of the machines and personnel. All the
graphs were plotted against time.


1. AVERAGE RUNS PER MACHINE DAY plotted weekly for the entire unit.

This graph has proven very interesting. It begins on the 7th May 1944 when
the 6812th Signal Security Detachment had only one bombe in operation.
Operators and checkers as well as the repairmen were in the process of
being trained. The graph clearly shows the progress as the men obtained
experience and as each new machine was added to make the final ten. The
average runs per machine day increased from 32 runs on 14th May 1944 to an
average of 73.3 runs per machine day on 6th May 1945. To understand how
much of a record this increase in output really was the following graph
must be seen.

2. AVERAGE RUNS PER MACHINE DAY ALL STATIONS plotted monthly. The

figures from which the points on this graph are plotted are furnished by
the British from Bletchley Park. Time sheets covering each days work were
sent to BP daily covering the previous days work. This was done by all of
the Out Stations operated by the British also. The figures were averaged at
BP and a copy of the results furnished each Station monthly. Graph No.2
shows U.S.A. plotted along with the other five British Stations, for the
period during which the figures were made available. At the time operations
ceased the average for U.S.A. was approximately 25% above that of the
British and increasing rapidly

3. AVERAGE RUNS PER DAY PER WATCH plotted weekly. This graph

graphically shows the output of each watch. It can be seen that A and D
Watches were almost constantly above the average in output. The various
fluctuations almost always have a definite reason as in the case of the
large dip in the output of B Watch on 25 March 1945.

4. AVERAGE NUMBER OF RE-RUNS PER MACHINE PER DAY plotted weekly. The

top line of this graph shows the average number of runs per machine per
day. From this line the average number of re-runs per machine per day is
subtracted thereby giving another line or graph representing the actual
useful runs per machine per day. The red area between the two can be called
"lost work" or "lost effort" because of some error thereby requiring that
the work be re-run. It can be seen that the number of re-runs varied
between 5.2 and 8.5 over the entire time of operations.

5. AVERAGE RUNS PER DAY PER MACHINE plotted weekly. This set of

graphs definitely shows the output of each machine and its general running
condition. Those machines which gave the most trouble as far as repairs are
concerned can be easily seen by the dips in their graphs. This set of
graphs also reflects to some extent the abilities of the engineers and
technicians to keep the machines in repair and good running order.

6. BAR GRAPHS SHOWING TROUBLE TIME PER MACHINE plotted for each

machine daily. This set of graphs shows the actual out of action time for
each machine daily. No other graphs show so well how the abilities of the
engineers and technicians improved. The total out of action time dropped
from 247.5 hours in January 1945 to 69 hours in April 1945. The four Watch
Engineers are to be highly commended for their superior work. T/3 Jack
C.Kemp, T/3 Malvern A.Schoch, T/3 Horace T.Chandler and T/4 James M.Church
were each awarded on 22 May 1945 the Certificate of Merit European Theater
of Operations U.S.Army for their superior performance of duty.



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