Table 2-1. Operator's Inspection Chart for Plotting Board M17 and Caring Case M72

Table 2-1. Operator's Inspection Chart for Plotting Board M17 and Caring Case M72

Point of

Accepted standard

Figure

inspection

PLOTTING BOARD M17

When the azimuth disk is assembled on the base (fig. 12), it shall be rotatable to any

Alinement

12, 1-3, and 1-4

required position. The index line on the base (fig. 1-3) and the centerline on the

disk (fig. 1-4) shall be in coincidence when the disk and the index mark on the

base are alined.

The azimuth disk shall be clean, flat, and in good condition as explained in the preced-

Azimuth

ing text and shall rotate freely on its central pivot point to any azimuth position.

disk

The pivot point shall be a snug fit on the pivot.

The base surface shall be clean, flat, and in good condition as explained in the pre-

Base

ceding text.

Pivot

The pivot, secured in the base, shall not be loose or bent.

CARRYING CASE M72

One snap fastener shall be secured in the carrying case. It shall not be destroyed or

Snap

fastener

loosened in the case fabric, and shall properly hold the cover flap in a secure and

closed position.

The loop of the carrying case is secured by stitching to the reverse or back side (not

Loop

1-1

shown in the illustration indicated). It shall be securely fastened to the case. The

stitching shall not be loose or torn.

(3) To determine the distance on the plot-

2-7. Operation

ting board from the first point to the second point,

a. The theory of operation of the plotting

divide the stated distance by 50 or 100 (depend-

board is simple and the accuracy of the results

ing on which scale on the grid pattern (fig. 13)

depends on the skill of the operator. The plotting

is used). The result is the number of squares on

board is used to plot accurately the relative posi-

the grid pattern between the two points. Count

tions of the weapons, base points, and targets

off the number of squares, or fractions of squares,

and to determine the directions and distances

thus determined from the first point toward the

between these points. The size of the dots placed

top of the plotting board and plot the second

on the plotting board affects the accuracy of the

point. The second point may be plotted also by

data determined. The dots shall be made as

measuring off the stated distance from the first

small as possible. To make it easier to locate

point toward the top of the plotting board using

these small dots, a small circle may be placed

the range scales on the disk.

around each slot. In computing the data, be

d. When the distance and azimuths to the tar-

careful to use the dot and not the circle. Pencils

harder than 2H and gritty erasers should not be

get firing position have been determined from

the observation post, the azimuth and range from

used on the transparent plotting surfaces.

the weapon position to the target position (WT

b. An arbitrary point on the disk may be se-

= w e a p o n to target) is determined as indi-

lected as the weapon position or the observa-

cated in (1) through (4) below.

tion post. Whenever possible, the center (pivot

(1) Use the pivot point (figs. 1-3 and 14)

point) of the plotting board is used to represent

as the observation post.

either the weapon position or the observation

(2) The locations of the firing position and

post.

the target, as obtained at the observation post

c. To plot a point with a given azimuth and

in terms of azimuth and distance, are plotted

distance from another point, proceed as indi-

individually on the movable disk.

cated in (1) through (3) below.

(a) Set the azimuth scale (fig. 14) gra-

duation corresponding to the azimuth over the

(1) Select an arbitrary point on the disk

index mark (fig. 13).

as location of the first point and place a pencil

(b) Mark each location with a pencil dot

dot. (If the pivot point is selected as the arbitrary

over the index line at the point on the range scale

point, it is not possible to make a pencil dot).

corresponding to the distance in meters. Each dot

(2) Rotate the azimuth disk on the base (fig.

is plotted toward the top of the plotting board.

12) until the stated azimuth is indicated over

(3) To determine the azimuth between the

the index mark.

2-3