comdtinst m2400.1f - US Coast Guard Response Boat-Medium

C. Functions of the System.
1. Distress Alerting. Distress alerting is the rapid and
successful reporting of a distress incident to a RCC or
another ship in the vicinity. When an alert is received by an
RCC, normally by a coast station or coast earth station, the
RCC will relay the alert to SAR units and to ships in the
vicinity of the distress incident.
2. Distress Alerting Range. Distress alerting may be made in
the ship-to-shore, ship-to-ship and shore-to-ship directions
in all sea areas. Ship-to-ship alerting is effective for
about 100 miles. Distances beyond 100 miles will depend
entirely on ship-to-shore alerting using satellite and/or HF
communications.
3. Distress Frequencies. Ships in sea areas A3 and A4 would
transmit a ship-to-ship alert on 2187.5 kHz and a
ship-to-shore alert by a ship earth station, HF communications
or a satellite EPIRB as appropriate. Ships in sea area A2
normally would transmit a ship-to-ship and a ship-to-shore
alert on 2187.5 kHz and ships in sea area A1 would
transmit a ship-to-ship and ship-to-shore alert on channel
70 (156.525 MHz).
4. EPIRB. Distress alerts will normally by initiated manually,
except when a ship sinks and a float free satellite EPIRB is
initiated automatically. All distress alerts will be
acknowledged manually.
5. RCC. Distress alerts relays from an RCC to ships in the
vicinity of a distress incident will be made by satellite
communications to ship earth stations and by terrestrial
communications using appropriate frequencies. An "area call"
would normally be used to alert ships in the vicinity of a
distress incident. Ships in the area addressed would
establish communications with the RCC for SAR coordination
purposes.
6-3