July-August - Air Defense Artillery School

Practice Spotting Trainer:
By Lieutenant Colonel Joseph S. Piram: Coast Artillery Corps !:
i\ lost Coast Artillerymen realize that spotting training
and fire adjustment training for Seacoast Batteries present
many problems and that accurate spotting with green men
is very difficult of attainment.
Va~ious methods of training spotters have been devised
and published in pertinent regulations, manuals, and the
COAST ARTILLERY JOURNAL, and actual training has been
given by use of aids previously described and published,
some of which have consisted of firing on a small pond or
lake with a rifle or other small caliber weapon; use of a toy
boat and a piece of cotton suspended by a string: and actual
training by spotting the splashes of other batteries firing
on a target.
All of these methods are excellent for the training of
spotters, but, unfortunately, in many cases, due to conditions,
lack of facilities and cost, certain of these methods
cannot be employed.
In a desire to construct some trainer which could be
built cheaply and serve the purpose under any conditions,
the spotting trainer described below was devised. This
trainer utilizes principles previously employed and c06rdi-
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nates them into a simple board capable of being used
either indoors or outdoors at very little cost.
This trainer is capable of being knocked down for transportation,
into the board proper, components of the "A"
frames, detachable fishing reel and bracket, curtain, and
other small parts. The board is designed so that it can be
ad justed for tilt and height.
The plywood board has }s inch drilled holes bored into
it, is painted a blue green with occasional whitecaps, and is
numbered on the under side. A slit is constructed for the
course of a model vessel which acts as a target. By means of
a fishing reel, fish line, pulleys and a weight, an operator
under the board places the target on a moving course.
Another operator connected to the B.G station of the batterv
(or other convenient location when the board is used
alo'ne) pushes up cotton swabs to represent the splashes at
the appropriate times, and two spotters, using 1\ 1191 0 or
i\1191OAl azimuth estimates (or a single spotter) read(s)
either the spotted deviations with reference to the target
or sense(s) overs and shorts. A screen of porous cloth
painted green is placed around the board to keep the spottef\
from determining the instant or approximate location at
which the operator will push up the swab.
For initial training of green men the model target can Ix
placed at any stationary position on the board and, by uS(:
of the numbers stenciled below the board, the swab c-an
be pushed up in several numbered positions previoush
determined by the instructor and upon which accurate
spotted deviations or sensings by an e~l)erienced spoue!
have been made to check the accuracy of the student spot
tel's. Further, by use of the Dispersion Tape and Scale
outlined in Appendix I to Fl\l +10 and the numbered holeof
the board, a predetermined spotting problem can be se'
up for co(irdinated drill by the entire battery.
The trainer may be used to train spotters indi\'idually. or
a system can be used wherein a small baseline is set up in
front of the hattery (length of baseline between spottin~
instruments and distances from the board to the trainer i,
dependent on the length of the model boat used), with the
trainer placed in front of the instruments. A field line con
nects the B.G station with the operator handling the cotton
swabs, and field lines connect the spotters to the spotti~4
section in the plotting room. By use of a stop watch Inl