Page 47 - NAVAL SCIENCE 3 TEXTBOOK

52 NAVAL KN OWL EDGE

A signalman mans his light aboard the aircraft USS George Washing-
ton (CVN 73). (Joseph Hendricks)

in classified signal books held by ships in the allied navies and in
international codebooks carried by aLi naval and merchant vessels
on the high seas.
There is a signal flag for each letter of the alphabet, one for
each numeral from zero to nine, and others with special uses. A
total of sixty-eight flags and pennants can be used to send thou-
sands of signals. Decks of signal cards are available to use in learn-
ing the signal flags and pennants.
Flashing light. Signaling by flashing light can be done either by
day or night either by using a signal light pointed at an addressee
or by yardarm blinkers, which aLlow it to be seen omnidirection-
ally (360 degrees). The message is sent by means of international
Flaghoists are read from the top down, outboard to inboard. Flaghoist Morse code, with "dots" and "dashes" of light formed by opening
signals used for tactical communications and maneuvering are based
on the standardized Allied Naval Signal Book. and closing shutters across the face of the signal light. The trans-
mitting signalman sends one word at a time with a slight pause

light, only those in the line of sight. Visual signals include f1aghoist,
semaphore, and flashing light (signal light).
Visual communication is versatile, reliable, silent, and econom-
ical. It can be used to talk with merchant ships or foreign mariners
who cannot easily communicate in English, through the use of
standardized international codebooks. Further, it has the advantage
of using simple equipment that does not often breal< down. Visual
signaling is efficient and economical because it shares the communi-
cations load with radio while not using the electronic frequencies.
The signal bridge can perform all the functions of radio except
for long-distance communications. The signal force identifies other
shipping and chaLlenges unidentified vessels and sometinles aircraft.
Flaghoist. Flaghoist signaling is a rapid and accurate system of
sending tactical signals or international code during daylight. A
f1aghoist signal system can send maneuver instructions more uni-
formly than any other system. Signals are repeated by those receiv-
ing them, thus ensuring that the message is received accurately.
A signalman uses semaphore flags to send a message to a nearby ship.
Meanings of signals that may be sent by f1aghoist are contained (Greg Messier)