The two types of train and elevation zero align-
ment are equipment with alignment or boresight tele-
scopes and equipment without telescopes.
Equipment with alignment or boresight tele-
scopes: Train zero is defined as the angle at which the
telescope axis is parallel to the ship’s centerline plane.
Elevation zero is that angle at which the telescope axis
is parallel to the RPP. Train and elevation zero align-
ment is carried out by physically positioning each
equipment to train and elevation zero by using sur-
veying techniques and zeroing the dials and synchros,
or by compensating for the train and elevation errors
through computer software changes.’
Equipment without telescopes: Train and
elevation zero alignment is accomplished by matching
an indicator to a scribe mark or plate and zeroing the
dials and synchros.
PERFORMANCE OF TRAIN AND ELEVATION
SPACE ALIGNMENT
(STAR CHECKS)
The sixth major step of initial alignment is train
and elevation alignment between the alignment
reference and other combat systems equipment. This
is accomplished by comparing equipment position
when the optical axes are made parallel by sighting on
a celestial body. If the train and elevation readouts for
the equipment do not agree within the operational
tolerances previously established for that equipment,
alignment is necessary. After corrective alignment is
accomplished, a new set of tram or benchmark read-
ings must be taken and recorded. This alignment
check can be performed by a ship’s force or a support
activity.
ESTABLISHMENT OF BENCHMARK
AND TRAM REFERENCE READINGS
The seventh and last major alignment step is the
establishment of reference readings that are performed
by a support activity or a ship’s force. Reference read-
ings are established to furnish an easy means of
checking train and elevation alignment in the future.
This is necessary because the dials or synchros may
become misaligned as a result of vibration and normal
wear or equipment disassembly for the replacement of
worn parts.
Tram and benchmarks are provided to facilitate
checking combat systems equipment at a definite train
and elevation position. The position selected may be
any convenient value within the limits of the equip-
ment movement. The dial readings for these positions
are recorded on the sheets provided in the alignment
smooth log. If the equipment remains aligned cor-
rectly for zero train and elevation, the recorded dial
readings are the same whenever the equipment is
moved to the tram or benchmark position.
The alignment verification obtained by using a
benchmark is accurate only if the angle between the
reference line and the position of the pointing line
established by the benchmark does not change as a
result of hull distortion or some other cause. Adjust-
ments to equipment should not be made by using the
result of a single benchmark check. Instead, bench-
mark results should be recorded each time they are
performed so that a determination can be made when
a benchmark error begins repeating itself and becomes
an indication that further alignment checks are re-
quired.
Tram bars and tram blocks may also be used to
establish an angle by determining a definite distance
between a point on the rotating structure of the equip-
ment and a point on its fixed structure. An error, as
defined by tram readings, may also result if the fixed
structure shifts on its mounting. Any adjustments to
equipment, like benchmarks, should not be made on
the basis of a single tram check.
Some equipments have both benchmarks and
trams. When the benchmark reading changes and the
tram reading remains unchanged, the extent of hull
distortion is revealed.
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