A signal requiring the indication of position to
complete its signification should be signaled as
follows:
CH L2537N G4015W—Vessel indicated is
reported as requiring assistance in lat. 25°37'N
long. 40°15'W.
Distance
Figures preceded by the letter R indicate distant
in nautical miles.
Example:
OM A080 Rl0—Bearing and distance by radar of
vessel indicated are bearing 080°, distance 10
miles.
The letter R may be omitted if there is no
possibility of confusion.
Speed
Speed is indicated by figures preceded by
1. the letter S to denote speed in knots, or
2. the letter V to denote speed in kilometers per
hour.
Examples:
BQ S300—The speed of my aircraft in relation to
the surface of Earth is 300 knots.
BQ V300—The speed of my aircraft in relation to
the surface of Earth is 300 kilometers per hour.
Time
Times are to be expressed in four figures, of which
the first two denote the hour (from 00—midnight up
to 23—11 p.m.), and the last two denote the minutes
(from 00-59). The figures are preceded by
1. the letter T, indicating local time, or
2. the letter Z, indicating Greenwich mean time.
Examples:
BH T1045 L2015N G3840W C125—I sighted an
aircraft at local time 1045 in lat. 20°15'N long.
38°40'W flying on course 125°.
RX Z0830—You should proceed at GMT 0830.
Time of Origin
The time of origin may be added at the end of the
text. It should be given to the nearest minute and
expressed by four figures. Apart from indicating the
time a signal originated, it also serves as a convenient
reference number.
Communication by Local Signal Codes
When a vessel or a coast station wishes to make a
signal in a local code, the signal YV1—“The groups
which follow are from the local code”—should
precede the local signal in order to avoid
misunderstanding.
FLAG SIGNALING
A man-of-war desiring to communicate with a
merchant vessel will hoist the CODE pennant in a
conspicuous position and keep it flying during the
entire time that signals are being made. This indicates
that the signal groups are from the International Code
of Signals.
Groups from the International Code of Signals
may also be used between allied naval ships. They may
be used alone or to supplement basic signals from the
Allied Maritime Tactical Signal and Maneuvering
Book, ATP 1, volume II. Whenever military use is
made of the Code, groups will be preceded by CODE
when transmitted by flaghoist, or INTERCO when
transmitted by Morse, voice, or hand flags. When only
international signals are used, CODE/INTERCO
followed by TACK are to be used as the first group to
indicate that all of the following groups are taken from
the Code. When used to supplement other signals,
CODE/INTERCO immediately precedes the signal
group to indicate that only the one group is taken from
the Code. When using international signals to
supplement signals from ATP 1, volume II, or when
international signals are preceded by a naval call
sign, naval procedure is used. Under all other
circumstances, international procedure is to be used.
As a general rule, only one hoist should be
displayed at a time. Each hoist or group of hoists
should be kept flying until it has been answered by the
receiving station. When more than one group are
shown on the same halyard, they must be separated by
a tackline. The transmitting station should always
hoist the signal where it can be most easily seen by the
receiving station; that is, in such a position that the
flags will blow out clear and free from smoke.
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