A study by the official U.S. Navy Pacific Photo-Interpretation Unit of aerial
photographs of Japanese occupied areas in the Solomon Islands, reveals that the
plan of enemy medium and heavy antiaircraft battery positions usually follows one
of three patterns: that of an arc, a triangle, or a rectangle. A typical battery
position is shown in figure 1.
a. Ground Patterns
(1) Arc Pattern
The arc pattern includes 3 to 10 emplacements. The radius of the arc
usually varies directly with the number of guns in the pattern. These batteries
are frequently reinforced with a few scattered light AA positions. The CP of the
arc battery is located back of the battery, approximately equidistant from the
ends (see figure 2). Gun crew quarters and ammunition dumps can usually be
observed at the edge of the clearings in which the batteries are installed. One
noteworthy battery consists of a series of three arc patterns, the center one of
the three being reversed in direction from the end two. This battery is located
(2) Triangular Pattern
This is a three-gun installation in the shape of a triangle. The CP is
usually located in the center of the position. It is similar to the arc and rectangular
positions in all other respects (see figure 3).
(3) Rectangular Pattern
The rectangular position is a four-gun battery built in a roughly rectangular
pattern. This pattern is more of a trapezoid but for purposes of classification,
patterns of this type are classified as rectangular. This type of battery has a
CP in the center of the position. Crew quarters, ammunition dumps, etc., are
removed from the position as in the case of the arc pattern; if the position is in
a clearing they are located at the edge of it (see figure 4).
b. Revetment Types
(1) Circular Revetment
The revetments that the Japs build are usually circular. In most instances
they have no entrances. Some have been observed with a protected entrance, and
a few with an unprotected gap. These revetments vary in size from 12 to 33 feet
inside diameter. Most of them appear to be slightly countersunk. The revetment
is probably built up of sandbags or some similar material (see figure 3).
(2) Modification of Circular Revetment
At Vila a new type revetment has been observed. This consists of a ramp
leading down into the opening of a covered shelter, probably for ammunition
storage, which in turn opens directly into a circular gun revetment. Another
revetment is built around the first. Several of this type were observed in a battery
(see figure 5).
(3) Spiral Revetments for MG or Light AA
At Munda a spiral sloped revetment was observed. The inside diameter
was approximately 10 feet. The purpose of the spiral was to form a protected
entrance. The spiraled wall continued about 3 feet beyond its beginning.
c. Location of Batteries
The location of batteries relative to a landing strip is highly variable. In
most instances batteries have been built in natural clearings and elevations. This
is illustrated by a comparison of figures 6 to 9.