On Mon, 14 Mar 2005 19:46:25 GMT, Bruce in Alaska
wrote:

snippage

Nice explanation Chuck.

I would add just a few thoughts to the above.

First: Radio Prodceedures are covered extensivly in 48CFR80 starting at
80.311. Only the Master, of a US Flagged vessel, or the person
responcible for the vessels Radio Station, (Radio Officer) may
authorize the transmission of a Distress Signal, or Urgency
signal. (Mayday, Pan Pan)
Second: Urgency Siganls differ from Distress Signals in that Urgency
Siganls are messages that carry Distress Information that are
about another Station, and NOT the Transmitting Station. That
is why USCG use the "Pan Pan" Urgency Signal preceeding any
message that concerns a "Reported ship in Distress", and it
means that the information passed is in regard to a MayDay
Call received and reported. This is opposed to a MayDay Relay
Signal which is sent by a vessel that is relaying an initial
Mayday Signal for a Distressed Vessel, that may not have been
received and a Acknowledged by the appropriate Agency. (USCG
for US Waters)

In Canada, we use "Mayday Relay" to relay a message from a distressed
vessel (and a US book I have also uses "Mayday Relay" for this
purpose).

Normally, when a vessel makes a Mayday call, the Coast Guard will
respond and verify the details, then do a "Mayday Relay" to
re-broadcast the distress message.

A "Pan Pan" or Urgency message indicates that the vessel has an urgent
message concerning the safety of a ship, aircraft or other vehicle, or
the safety of a person. The Coast Guard will also use a "Pan Pan"
message to relay a vessel's Urgency message.

In practice, the Urgency call is used when a vessel requires
assistance, but is not in grave and imminent danger (the requirement
for assistance is often not particularly urgent, but we don't have any
lesser grade of call.)

Although "Mayday" officially indicates the _vessel_ is in grave and
imminent danger, you are unlikely to be shot if you use it for man
overboard or serious medical emergencies. Even if Urgency is used for
these situations, I expect they will be handled with top priority.

Third: The Silence Signal (Seelonce Mayday) is used by the sender
of the Distress Signal, to initiate a Quiet Frequency for
the purpose of passing Distress Traffic. It may apply to
individual Stations, OR All Stations. The Distressed
Station MAY deligate control of the Frequency to another
Station at its discression. It is resinded by sending the
Silence End Signal. (Seelonce Feeenee, or Pru-donce)
Fourth: Order of Priority is:
1. Mayday (Distress Signal)
2. Pan Pan (Urgency Signal)
3. Sellonce Mayday (Silence Signal)

A "Seelonce" message doesn't have a place in the priority list - it is
just a message indicating that a Top Priority (Distress) situation
exists.

4. Securite (Security Signal)
5. all other traffic


Bruce in alaska wondering if this is going to start another jackieboy
rant.......

--
Peter Bennett, VE7CEI
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