withstand high vibratory shock and extreme humidity
conditions and operates equally well in hot or cold
Naval searchlights are used to project a narrow
his searchlight may be furnished for operation
for visual signaling. To accomplish its purposes, the
either with a 60-hertz, 115-volt transformer to step the
searchlight must have an intense, concentrated source
voltage down to 28 volts or without a transformer to
of light, a reflector that collects light from the source (to
operate on 115 volts using the proper rated sealed-beam
direct it in a narrow beam), and a signal shutter (to
unit. The same unit is available for use on small craft
interrupt the beam of light).
from a 28-volt power source.
Searchlights are classified according to the size of
The searchlight has four main parts:
the reflector and the light source. The three general
1. The base, which is equiped with a rail clamp
classes are the 8-inch, 12-inch and 24-inch searchlights.
for securing the searchlight to the rail.
The 8-inch searchlight is of the sealed-beam
incandescent type. The 12-inch light are of the
2. The yoke, which is swivel mounted on the base
incandescent and mercury-xenon type. The 24-inch
to allow it to be trained through 360°.
carbon-arc searchlight is not addressed in this manual.
3. The housing, which provides an enclosure for
Refer to Naval Ship's Technical Manual, chapter 422,
the lamp and is composed of a front and a rear
for information on this light
8-INCH SEALED-BEAM SEARCHLIGHT.--
4. The lamp, which provides the source of light.
The 8-inch signaling searchlight (fig. 4-28) uses an
incandescent sealed-beam lamp. It is designed to
The front section of the housing comprises the
shutter housing, and the rear section comprises the
backshell housing, containing a 115/28-volt step-down
quick-release clamp ring that permits easy replacement
of the lamp. The backshell and lamp assembly, when
detached, may be used as a portable searchlight. The
entire housing is mounted on brackets attached to the
shutter housing and supported by the yoke to allow the
searchlight to be elevated or depressed. Clamps are
provided for securing the searchlight in train and
The shutter housing contains the venetian blind
shutter, which is held closed by springs and manually
opened by a lever on either side of the housing. The
front of the shutter housing is sealed by the cover glass
and a gasket. The rear of the shutter housing is
enclosed by a gasket and adapter assembly. The adapter
assembly provides a locating seat for the lamp and
incorporates a hook and key arrangement that aligns the
backshell housing and retains it in position while
attaching the clamp ring to hold the two sections
Three filter assemblies (red, green, and yellow) are
provided and can be readily snapped in place over the
face of the searchlight. The shutter vanes can be locked
in the open position for use as a spotlight.
To remove the lamp from the housing for cleaning
Figure 4-28.--An 8-inch, 60-hertz, sealed-beam searchlight.
or replacement, use the following procedure: