"As I remember MOB (COB as is used today) is considered a MAYDAY, "
Not necessarily. A MAYDAY situation is any situation where there is an immediate threat of loss of property or life.
A MOB situation in 40F water would be a MAYDAY.
A MOB in 77F water at noon with flat water, would not.
In the latter situation, if there was no local traffic I'd probably not even use the radio. If there were other vessels in site, I'd probably call SECURITY to advise them why my vessel might be moving erratically and to let them know to stay clear of the MOB during recovery. In a channel or other area with heavy traffic and the chance someone would hit the MOB, I'd call MAYDAY, because that person was in danger of being run down by other vessels.
It's sometimes a fine line, left to discretion. The question is, are lives and property in IMMEDIATE danger of being lost? If not, you've only got a "damned inconvenience", not an emergency.
Steve, call me PI but as far as I'm concerned, a COB is what's left after I've eaten all the kernels on an ear on corn, and a ship will still be a "she", as long as I'm aboard. There are actually five genders in the human species (and that's not including surgical reassignments) and if any of the four "not male" types falls overboard and objects to me calling "Man Overboard!" I'll gladly keep silent.
Yah, in 50F water, everything has to be treated a bit differently. I'll bet your bottom paint works much better, too.
When I write I'll try to be proper but if someone goes overboard the call will be "Man Overboard". I'm not sure anyone would react to "Crew Overboard". A vessel will always be a she and I always use the proper traditional gender on board but since I started looking at equipment a few years ago and it took me a while to figure out what COB was the first couple of times I read it I thought I'd get with the program.
A funny story about the first MOB instance I experienced. I was in the Navy on our first night out from Bremerton. We weren't even out to sea yet still in the Strait of San Juan del Fuca. About 0200 and I had the watch down in our shop. I was reading and the PA (1MC) clicked on, "Man Overboard, Man Overboard astern...." my first reaction was "he didn't say 'this is a drill", my second reaction was a bit stronger "Oh s@#t, he didn't say 'this is a drill". We shaved a minute and a half off our best time in getting the ship mustered. Turned out some joker threw a light stick overboard thinking it would be funny. Bad conduct discharge for him. Nice to know all that drilling works when it's the real thing even though it turned out to be not the real thing.
Sorry. In any circumstancxes at all, A MOB is a PAN PAN call. Mayday is of direct and immininent threat to the VESSEL. Don't worry, hearing Pan Pan, Pan Pan, Pan Pan over the airwaves still gets you all the help you are ever going to get with a mayday.
If you need to conduct peculiar manuevering in a situation where others are likely to need to dodge you, then a securite call is indeed appropriate.
Remember the devisions.
Securite calls are low level notices of interest to feelow mariners regarding weather, hazzards to navigation and such. Securite calls are about making announcements, not requesting assistance.
Pan Pan calls indicate a danger or or crises beseting your crew or vessel that has not eyt put the vessel in iminant peril. Crew members becoming ill and requiring assistance, finding no way to start your motor (presumably on a day too flat to sail in) when you go to pull up anchor or (in our own case) having the stern gland implode and beging flooding the boat with water (however I believed that I could manage the situation so placed an advisory pan pan call to the CG, advising them that I wanted to handle it and retain control of my vessel, but that the situation might deteriorate quickly and I would appreciate them keeping an ear out for us).
Mayday call. Vessel in immediate distress. At this point you are pretty much relinquishing command of your vessel to your rescuers. The stament is that you are willing to abandon ship and are asking to be taken off.
The reason that "in the odlen days" Mayday calls were so much more likely to get a response then the lesser Pan pan calls was that the salvage boats would also come out. So you were getting the attention of people that wanted to pirate...errr...salvage your vessel as soon as your feet left the deck and make some money off the deal as well as the good old Coat Guard. This is not so much of an issue nowadays, nor for our class of vessels, nor in 99% the waters we sail...so do not feel the need to overuse it.
P.S I have now done two "for deadly real" COB rescues. One when I was the only pone left on the boat in really crappy conditions and when when I was part of a larger crew and somoene did something stupid in fairly calm and controlled bay waters (albeit in a narrow channel, with heavy traffic and bad shallows on either side restricting manuevering). Not the most fun thing in the world. Having time for radio calls of any sort in the first instance was completely out of the question. In the second instance, with the 8man crew, there was little need.
"Mayday call. Vessel in immediate distress. " That's not the way I've seen it defined by the FCC or USCG. (Eldridge actually says if "...You are in distress...threatened by grave and imminent danger" you, not the vessel). Every formal definition I've seen of MAYDAY defines it rather simply as the EMERGENCY call, and further state and federal laws further define "emergency" as a situation where there is "imminent risk of loss of life or property". I mention especially the FCC, because they regulate all radio transmission in the US, and by both FCC regulation and international convention, "Mayday" is specifically defined and used that way in all radio services--not just the maritime ones. A Mayday call invokes and receives special rights on any radio frequencies.
What Chapman or Eldridge or anyone else define "Mayday" as, doesn't define it until they relieve the FCC of duty and take over the watch.
SECURITY and PAN are not emergency calls, that's the difference. Eldridge calls "PAN" an "Urgency" call, which might be a good way to describe it--expectable danger is coming, just not imminently.
The bastardization "Mayday" derives from the French term "M'aidez" meaning, literally, "aid me" or "help me".
That includes situations where the vessel is not at risk, but someone onboard is, i.e., a steam pipe bursts and gives crew 3rd degree burns requiring medevac. Or, your trimmer has just amputated his fingers in a genoa winch. He'll live, the boat is in no danger, but an immediate medevac might re-attach those fingers. Or, you've witnessed a collision between two other vessels, and they are on fire or sinking with crew in the water.
Those are all emergencies, all Mayday situations, none of them involve distress to your vessel. You're still entitled and encouraged to call Mayday in all of them.
I have just completed a course and been awarded a Marine Radio Operators Certificate of Proficiency (a requirement for using both VHF and HF here). The extensive 130 page handbook issued by the Australian Maritime College which is based on the International Radio Regulations contains the following:
"56.2 The [Mayday] signal indicates that the vessel or person using it is threatened by grave and imminent danger and requests immediate assistance."
Note the reference to "vessel or person using it".
"56.3 The distress signal must not be used under any other circumstances"
"56.4 It should be noted that the use of the distress signal is only justified if the vessel or person using it is threatened by grave and imminent danger. It does not extend to situations where immediate assistance is sought on behalf of a person, for example, a medical emergency. The urgency signal should be used in these situations"
Therefore, if a person falls overboard, and it is not the person using the vessel, then it is clear that the Mayday call is NOT appropriate.
The handbook describes the use of the urgency signal (Pan Pan) as follows:
"67.2 Use of the urgency signal indicates that the station sending it has a very urgent message to transmit concerning the safety of a vessel, aircraft, or person."
Section 66 describes the situation "Transmission of a Distress Message by a Station not itself in Distress", including where the vessel in distress cannot transmit, or where further help is necessary (eg where you arrive on scene and need more help), or where you hear a Mayday that has not been acknowledged. In all these cases the signal "MAYDAY RELAY" is used.
Marine Radio protocols are of an International standard and apply everywhere.
Of course, we are likely to be in agreement, He is a local and I think we may have done our radio operators tickets at the same place (Sandringam Coast Guard, by any chance, Graham?).
I also think I recognise the name of your boat and may have seen it in my forays to Hastings.
As for seeing two boats collide, catch fire and begin sinking, as used in in earlier example, it is indeed a MAYDAY RELAY call. If you are hearing the stricken vessels call but cannot hear a response, then you can make the call on your more functional equipment...or just be proactive if you do not hear any radio traffic from the vessels and make the MAYDAY RELAY call on their behalf. If you hear radio traffic between the stricken vessels and a coast radio base, then the best thing you can do is shut up and leave the channel clear until they ask for other boats in the area who can render assistance. (Though I can think if a situation in which I would make a super quick call to announce that I was standing by close at hand and was willing to assist).
P.S The time that the stern gland blew ou and I issued the Pan Pan call, The coast guard decided to relay to a water police vessel that was near at hand and they came along and shadowed us from about 50 meters away, ready to render assistance if our situation changed. So it is not that Pan calls are not taken seriously around these parts.