Figure 2-22.—Marine barograph.
proper use and maintenance of the equipment.
NAVMETOCCOMINST 3144.1 also provides
guidance on replacing charts, rewinding the clock,
conducting time and pressure checks, and making other
adjustments.
REPLACING THE CHART.—Charts (fig. 2-23)
should be replaced every 4 days at 1200 UTC (and on
the first day of each month). Fill in as much of the chart
identification data as possible before placing the chart
on the barograph. All time should be set and entered in
UTC. Add the station elevation to the nearest foot if a
space is not already provided on the chart. Lift the pen
arm from the chart and remove the chart cylinder from
the barograph. Remove the old chart, and then place the
new chart on the cylinder. The trailing edge of the
pressure/time graph should overlap the chart
Identification-Data section, and the edge of the paper
should be aligned under the metal spring clip. Complete
the entries on the old chart for ship’s position, date, and
(chart) off pressure, date, and time. Rewind the clock
mechanism.
REWINDING THE CLOCK.—Although the
clock has an 8-day mechanism, it should be rewound
every 4th day, when replacing the chart. Seven to eight
pulls on the lever inside the cylinder is sufficient to
rewind the mechanism. Place the cylinder on the
barograph; align the correct time line with the pen point;
and lower the pen point onto the chart. Check the
pressure.
REINKING THE PEN.—A glass rod is used to
transfer a drop of purple recording ink to the pen tip.
Very little ink is needed, and the pen is considered
adequately inked if the pen tip cavity is half full. The
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