Appendix I, Continued
PRO WORD.Pronounceable words or
phrases that have been assigned meanings
for expediting message handling on radio
circuits where procedure is used.
PSYCHROMETER.A type of
hygrometer (an instrument for determining
atmospheric humidity) consisting
essentially of dry-bulb and wet-bulb
PULSE-REPETITION RATE.The rate at
which recurrent pulses are transmitted,
usually expressed in pulses per second.
QUARTERDECK.The portion of the
weather deck designated by the
commanding officer for official
RADAR.(RAdio Detection And
Ranging) is a method of determining the
distance to and direction of objects by
sending out a beam of microwave radio
energy and detecting the returned
RANGE.Two or more objects in line.
RANGE MARKER.A distance marker,
as on a radar PPI.
RANGE STROBE.An electronic range
marker on a radar PPI.
RECIPROCAL.A direction 180° from a
REFERENCE SHIP.A ship to which
relative movement of other ship is referred.
REFRACTION.The change in direction
of motion of a ray of radiant energy as it
passes obliquely from one medium into
another in which the speed of propagation
RELATIVE BEARING.Bearing relative
to heading or to the ship.
RELATIVE MOTION.Apparent motion;
RELATIVE MOVEMENT LINE.A line
connecting successive positions of a
maneuvering ship relative to a reference
RELATIVE PLOT.A plot of the
successive positions of a ship relative to a
reference point, which is usually in motion.
ROOT MEAN SQUARE.The square
root of the arithmetical mean of the
squares of a group of numbers.
RUNNING FIX.A position determined
by crossing lines of position obtained at
different times and advanced or retired to
SAILING DIRECTIONS.A descriptive
book for the use of mariners, containing
detailed information of coastal waters,
harbor facilities, and so forth, of an area.
SCALE.The ratio between the linear
dimensions of a chart, map, drawing, and
so forth, and the actual dimensions