Solving of Survey Notes

4. As the deflection setting on the sight

plotted, count up 500 meters and make a pencil

is right 30, the deflection to be given to the

dot. This is the location of the second section.

weapon is right 35 (right 30 plus right 6 to the

Note. To determine the azimuth and distance

nearest 5-mil graduation).

from the first section to the second section, rotate the

disk until the plotted location of the second section is _

d. Solving of Survey Notes.

toward the top of the plotting board and is on the same

(1) Given. The weapon personnel are placed

vertical line, or the same distance from the same

vertical line, as the first section plot (in this case on the

in position by section, each section in a different

red index line). The azimuth is 4134 mils and the distance

location. The first section is plotted at the pivot

is 861 meters.

point of the plotting board. The second section is

located (surveyed) with reference to the first sec-

2-10. Accuracy

tion by compass and pacing. A traverse of two

legs is made to the second section from the first

a. With one extremity of the dial index line in

coincidence with each of the diametrical center-

section.

lines of the base, the other extremity of the index

( a ) First leg:

Azimuth 3800

line shall not be more than 5 mils out of coinci-

Distance 400 meters

dence with the corresponding base centerline.

(b) Second leg:

Azimuth 4400

Distance 500 meters

b. The plotting board accuracy for the weap-

on-target (WT) line shall be within 5.0 mils

(2) Procedure. To plot the location of the

as determined by placing pencil dots at the tar-

second section with reference to the first section,

g e t (T) and weapon (W) points as measured

proceed as indicated in (a) through (c) below.

from observer (O) (represented by the center

(a) Use the range scale along the index

pivoting point of the dial) using the OT and OW

line.

values specified above. When a line is drawn

(b) Rotate the disk until azimuth 3800 is

through the WT dots, the WT line is then laid

at the index mark. Count up 400 meters along

the red index line and make a pencil dot.

parallel to the base O centerline (index line, fig.

13) and the WT mil value is determined from

a t the index mark. From the pencil dot just

the mil scale (azimuth scale, fig. 1-4) on the dial.

OPERATION UNDER UNUSUAL CONDITIONS

Section III.

c. Do not permit the accumulation of snow or

2-11. General

ice on the plotting board. When not in use, al-

In addition to the normal operating procedures

ways keep the plotting board inside carrying case

for usual conditions described in section II, spe-

M72 to prevent such accumulation and/or dam-

cial instructions for operating under unusual con-

age or destruction.

ditions are contained herein. In addition to the

d. Never apply heat from strongly concen-

normal preventative-maintenance services, special

t r a t e d sources directly to an extremely cold

care in cleaning and handling must be observed

plotting board. Sudden great temperature changes

where extremes of temperature and atmospheric

may cause breakage of the component parts of

conditions are present. Proper cleaning and hand-

the plotting board or it may result in nonadher-

ling not only insure proper operation and func-

ence of the bonded components due to "breaking-

tioning, but also guard against breakage and/

up" of the bond.

or deterioration of the materiel.

2-13. Operation under Dusty or Sandy

Conditions

2-12. Operation in Extreme Cold

Under extremely dusty or sandy conditions,

a. In temperatures below freezing, it is neces-

extra care must be exercised when cleaning the

sary that extra care be used when handling the

plotting board so that scratching of the trans-

plotting board. Extreme cold will make the plas-

parent plastic s u r f a c e s d o e s n o t o c c u r .

tic material of the board more brittle, hence it

S u c h scratching will damage the transparent

will be more easily broken if dropped or struck

quality of the base grid and azimuth disk sur-

against other objects

faces. Excessive scratching will cause damage

b. Use a dry cloth for cleaning. A water dam-

and/or destruction of the lines of the vernier

pened cloth will either freeze to the plotting

and scales and render the plotting board difficult

board or it will leave a film of ice on the board

to read and/or useless. Shake all dust and sand

and make it inoperable.

from the carrying case.

2-6