The International Morse Code and special signals
are used for this means of communication. When
transmitting by whistle, siren, fog horn, or other
devices in which the length of sound can be controlled,
you use a short blast to represent a dot and a long blast
to represent a dash. When transmitting with a device
that is struck to create sound, such as a bell, gong, or
drum, use a single stroke to represent a dot and two
rapid strokes to represent a dash.
No heading or ending is used in sound signaling.
The text is to be made twice, separated by a pause.
The use of sound communication is normally
limited to certain specified sound signals. The ones
commonly used are those prescribed for vessels in the
Rules of the Road. When sound signals are used in
special circumstances, care must be exercised that
they do not conflict with the more commonly used
signals and thereby confuse ships and stations not
familiar with the special signals.
Sound signals other than those included in the
Rules of the Road are not to be employed in pilotage
waters and are only to be used in an emergency when
short range radio is not available, or for sounding
visual call signs on occasions when the OTC may wish
to ascertain which ships are within hearing distance.
Sound signals may only be used by the OTC or by
an individual ship having vital information for the
OTC. Signals made by any ship other than the OTC
are to be followed by the call sign of that ship.
When The OTC signals by sound, one ship usually
is directed to repeat back or receipt for the signal.
When sound is used by an individual ship, the OTC is
always to receipt for the signal with that ship's call
sign followed by the prosign R. The OTC may direct
another ship to receipt by making that ship's call sign
followed by the prosign K. The designated station
receipts by making the prosign DE followed by the
prosign R. No ship is to relay a sound signal.
The executive signal consists of a 5-second blast
immediately following the repetition of the text. The
execute to follow sign (IX) is not to be sent either in
the text or preceding the 5-second blast. The signal is
executed on termination of the 5-second blast. Ships
are not to wait for any ship that may be ordered to
repeat back or receipt. When ships are ordered to
repeat back, they are to include the executive signal if
one has been used.
IDENTIFICATION OF SHIPS
On occasion the OTC may wish to determine
which ships are within hearing distance. This may be
done by the OTC sounding the appropriate signal only
On hearing this signal, ships are to reply by
sounding their visual call signs once only as follows:
1. If addressed to one ship, immediately on hearing
2. If addressed to more than one ship, the ships will
answer in alphabetical order of call signs. If no ship
sounds within 30 seconds, the next ship in order is to
LEARNING OBJECTIVES: Define radio-
telephone (R/T). Describe the procedures for
operating the radiotelephone and maintaining
security; list precautions that should be
observed when communicating by
Radiotelephone (R/T) is used for voice tactical
and administrative communication by ships and
The time will come when, as a Signalman, you
will need to use the R/T. Study this section to improve
your ability to use voice communication procedures.
There can be certain drawbacks to using the R/T.
Poor voice communications (whether because of
faulty equipment, adverse atmospheric conditions, or
inept performance by an operator) can create
confusion, reduce reliability and speed, and adversely
affect operations. It is essential that all users observe
established operating procedures.
Basic guidance for voice radio communication is
contained in Communications Instructions Radio-
telephone Procedures, ACP 125. Various naval
publications prescribe procedures for specific