Ian Waugh - A Mariner\'s Guide to Marine Communications

• The DSC Distress Acknowledgement is an 'All Stations' call, and will
  be received by all vessels in the vicinity (not just by the casualty).
  In a distress situation, everyone who speaks on the distress channel
  starts with the word 'MAYDAY' once, at the beginning of each call.
  When Wizardcalculates her distance from and ETA to the casualty,
  that information would be forwarded to the casualty and to Falmouth
  Coastguard
  (More complete information on the conduct of a SAR operation is
  included in the IAMSAR Manual).

Your obligations to assist another vessel in distress are briefly described

in the International Aeronautical and Maritime Search and Rescue

(IAMSAR) Manual Volume Ill, which should be carried onboard all vessels.

The IAMSAR Manual refers you to other publications containing specific

obligations. Regarding radio procedures, points to remember include:

Ship'S masters are obligated to assist others in distress at sea whenever

they can safely do so. If you choose not to, your reasons must be recorded

in the radio log.

If other vessels have sent a 'Received Mayday', you can delay your own

voice acknowledgement until you know you are able to assist.

If you indicate that you are proceeding to assist, you must continue unless

released by the vessel in distress or other SAR co-ordinator;

Distress Communications - Sea Area A2 (MF Procedures)

Marine SSB radio with DSC should be your first choice system
for sending a Distress Alert, and the subsequent voice Distress Call and
Message, in Sea Area A2. Because you are in range of a MF DSC Coast
Station, the Coast Station/MRCC should receive your alert, call and
message; will acknowledge; and will co-ordinate any Search and Rescue
(SAR) operation in their area of responsibility. (Other GMDSS-fitted
vessels in the area will be monitoring 2187.5kHz and will receive your
DSC Distress Alert at the same time as the A2 Coast Station).

The radio procedures to be followed are shown below:

Action onboard Vessel in Distress

Send DSC Distress Alert on 2187.5kHz

indicating 2182kHz for follow-up voice

communications

Send voice Distress Call

and message on 2182kHz

80 THE NAUTICAL INSTITUTE

Action in A2 Coast Station

Receive DSC Distress Alert

on 21H7.5kHz

Send a DSC acknowledgement

Set watch 2182kHz

Acknowledge by voice

('Received Mayday')