distress. Distress traffic has priority over all other
traffic. All U.S. Navy communicators must be familiar
with distress signals to properly evaluate their meanings
and to take appropriate action when necessary.
If a ship becomes involved in a distress situation,
communications personnel should send distress
messages on normal operating encrypted circuits. If the
need for assistance outweighs security considerations,
the ships commanding officer may authorize the
transmission of an unclassified distress message on one
of the national or international distress frequencies.
When a ship in distress is traveling in company with
other ships, the ship in distress will transmit the distress
message to the officer in tactical command (OTC), who
will take appropriate action.
Several frequencies in different bands are
designated for the transmission of distress, urgency,
safety, or search and rescue (SAR) messages. The
following frequencies have been designated for use
during a distress or emergency situation:
500 kHz International CW/MCW distress and
2182 kHz International voice distress, safety,
8364 kHz International CW/MCW lifeboat,
life raft, and survival craft;
121.5 MHz International voice aeronautical
156.8 MHz FM United States voice distress
and international voice safety and calling; and
243.0 MHz Joint/combined military voice
aeronautical emergency and international
During SAR missions, the following frequencies
are authorized for use:
3023.5 and 5680 kHz International SAR
frequencies for the use of all mobile units at the
scene of a search. Also for use of shore stations
communicating with aircraft proceeding to or
from the scene of the search. CW and voice are
123.1 MHz International worldwide voice
138.78 MHz U.S. military voice SAR on-the-
scene use. This frequency is also used for
direction finding (DF).
172.5 MHz U.S. Navy emergency sonobouy
communications and homing use. This
frequency is monitored by all U.S. Navy ASW
aircraft assigned to a SAR mission.
282.8 MHz Joint/combined on-the-scene
voice and DF frequency used throughout NATO.
The control of distress message traffic on any
designated frequency is the responsibility of the station
in distress. However, this station may delegate its
responsibility to another station on the frequency.
Navy units at sea have always maintained listening
watches on distress frequencies. Communication
watch requirements vary according to the operational
mission of the ship and available equipment assets.
Ships in company normally divide distress watch
requirements among the group.
The technical control of the shore station that is
NECOS for fill-period terminations and PRI S/S
circuits must maintain a status board. The status board
should indicate, as a minimum, all systems/circuits that
are active, tuned in, or in a standby status. It should also
indicate all inoperative equipment. The watch
supervisors must verify the accuracy of the information
contained on the status board at watch turnover and
update while on watch. The status board must show the
following minimum information for active and standby
Functional title of circuit;
Frequency(ies), both send/receive, if fill-duplex
operation is used;
Circuit designator, from communication plan;
Transmitter and receiver designations;
For shore stations, keying line designations;
Terminal equipment designation (for example,
Cryptoequipment, keying material, and restart