COAST ARTILLERY, JOURNAL - Air Defense Artillery

MORTAR FIRE CONTROL -513
polations. The procedure indicated in c above minimizes the labor of
recording Case III firing data. When communications to a plotting
room have been interrupted the rate of change in range and azimuth
can be made use of in predicting azimuth and elevation for a'short time.
18. The check-back board referred to above was not used in the
last firings. Data were checked back over the telephones to the operators
in the plotting room. Pieces were laid in azimuth in the usual
manner. By means of a straight edge bolted to the racer and pro.
jecting therefrom each laying in azimuth was indicated by a chalk or
pencil mark. Any irregularity in the separation of these marks indicated
to the pit commander that his data were inaccurate and he ordered
relay. During these firings a time-azimuth check board, as described
in T. R. 435-221, was operated in the plotting room as a further
precaution.
19. The pit commander, knowing the capabilities of the gun sections
under him, selected and announced to the section the data to be
used in laying. The announcement of "two-bell data," "three-bell
data," or- "relay" by the pit commander served to indicate to the
mortar sections and, by phone, the B. C. station the particular data
posted on the special display board upon which it was expected the
pieces could be fired. When the pieces had been laid, the gun commanders
notified the pit commander of that fact by suitable signal.
The pit commander notified the battery commander's station by signal
(0V-e ring on 3D-secondand two ring£ on IS-second) that the pieces
were ready to be fired.
III-TESTS.
20. On May 7, 1924, the Battery Officers' Class from the Coast
Artillery School fired two very good service practices at Battery Anderson,
Fort Monroe, using most of the methods described.
21. The Battery Commander at Battery Anderson, who had familiarized
himself with, and aided in, the development of the special
methods and devices, obtained permission to use them in his annual
service practice. In May, 1924, two service practices were fired satisfactorily.
Again on :May24, 1924, during the Centennial Exercises at
Fort Monroe, these methods were used at service practice with satisfactory
results. During the summer of 1924 the C. M. T. C., R. O. T. c.,
and ~ational Guard units assigned to Battery Anderson found no difficulty
in firing by these methods.
22. The Com:tArtillery Board on September 29, 1924, submitted
to the Chief of Coast Artillery its report on Project ;'\0. II7, "Fire
Control Methods for Mortars," which included the following recommendations: