INSIGHTS: Man Overboard – The Mayday – Episode 4

A crew member overboard is something we all dread. We all know to hang on tight and not to fall in, but if a crew member does go over the side we need to know how to get back to them quickly and get them out of the water. Duncan Wells (RYA instructor, features writer and author) has provided a series of short articles for INSIGHTS on how to deal with a variety of possible MOB situations, including when sailing to windward and sailing downwind. Part 4 looks at the Mayday procedure.

Published 2 years ago

Episode 4 – The Mayday

In INSIGHTS Episode 1 we looked at the man going in when we were sailing to windward and how we would get the boat back to him and then a retrieval method using a 6 part tackle.

In INSIGHTS Episode 2 we looked at what we might do if the man went in while we were running downwind under a big downwind sail, a spinnaker or a cruising chute.

In INSIGHTS Episode 3 we looked at the MOB Beacons available to keep track of the man in the water.

In INSIGHTS Episode 4 we will look at the Mayday procedure.

Mayday – French for “Help Me”

Wherever you are in the world makes no difference to the Mayday procedure. How long you will have to wait until rescue does depend, however, on how far from shore you are.

Let’s start by defining a Mayday – from the French for “help me” – “m’aider”.

You call a Mayday when a vessel or person is in grave and imminent danger requiring immediate assistance.

If a person or vessel is not in grave and imminent danger requiring immediate assistance, but nonetheless needs help or assistance, then call a Pan Pan – from the French “panne” meaning breakdown. This can be upgraded to a Mayday by the rescuing centre, much as a Mayday can be downgraded.

An example of when you might call a Pan Pan might be if you have lost your rudder when 3 miles from shore and you want to notify the coastguard of the position while you try to fix it. The coastguard will monitor the situation because while you are currently not in grave and imminent danger, if you drift towards the shore you may well become so. From experience the coastguard will generally either upgrade this to a Mayday and send someone to take you under tow, or, leave it as a Pan Pan but still send someone to get you.

A speedboat that’s been driven up the beach and has called a Mayday will be downgraded to a Pan Pan while the coastguard establish the best course of action. Here, while it might be inconvenient, neither the vessel nor the crew are in grave and imminent danger. However, if someone was injured then a Mayday may still be relevant.

A member of crew who has caught their hand in a winch and is losing blood, someone who has slipped down the companionway, hit their head and is unconscious, or even someone who has fainted or collapsed and you cannot bring them round, the boat holed and sinking, the rig has fallen down, these are all Mayday situations.

So, how do we call a Mayday?

There are a number of ways. Digital and Manual.

Manual Mayday:

Let’s deal with the manual ways first.

We have all laughed at the “flames on the vessel” (as from a burning tar barrel or oil barrel), which is still listed in the International Regulations for the Preventing of Collisions at Sea (IRPCS). If any sailor tried that they certainly would have a Mayday.

But there are other internationally recognized distress signals;

  • A gun or other explosive signal fired at intervals of about a minute
  • A continuous sounding with any fog-signalling apparatus
  • Any signal by any signalling method consisting of … _ _ _ … SOS
  • Rocket shells throwing red stars fired one at a time at short intervals
  • The flag N (No) flown over the flag C (Yes)
  • Flying a ball over a square
  • A rocket parachute flare or a hand held flare showing a red light
  • A smoke signal giving off orange smoke
  • Raising and lowering outstretched arms

This last one (raising and lowering outstretched arms) I have seen. It was the Round the Island Race (round the Isle of Wight, UK). Approximately 400 yachts were making their way – bunched up – around “The Needles” at the SW corner of the Isle of Wight. It was mayhem! Controlled mayhem, however, because we were all very aware of each other. Suddenly we see a boat heading straight for us – as if to T-bone us. The skipper is waving his outstretched arms up and down and shouting, “We’ve lost our rudder, we’ve lost our rudder.” Luckily we were able to bear away and avoid him. He must have called a Mayday on the radio as I was aware of the Yarmouth lifeboat hovering around beyond the battling yachts waiting for their chance to come in and pick him up. But his Mayday signal in those circumstances was absolutely the right one.

Of course waving outstretched arms, flying flags or shapes and so forth will be absolutely no use mid-Atlantic with no one around to admire your in depth knowledge of the distress signals. Here you will need to transmit a distress signal.

Digital Mayday:

EPIRBs (Electronic Position Indication Radio Beacons) and PLBs (Personal Locator Beacons) will transmit a distress signal on 406mHz and this signal is picked up by the satellites and relayed to a Maritime Rescue Co-ordination Centre. In the UK this is Falmouth Coastguard.

The advantage of the EPIRB and the PLB is that you can alert someone a long way away. The disadvantage is that with most models you don’t get a response so you don’t know what is happening (see more about this in my last episode of Man Overboard).

There is however the new McMurdo FastFind ReturnLink PLB, which utilises unique functionality generated by Galileo satellite constellations’ “Return Link Service” to send a signal back to the FastFind ReturnLink beacon confirming the user’s 406MHz distress alert has been received and Galileo GNSS location coordinates have been detected. A reassuring blue light on the device flashes to confirm that signal and co-ordinates have been received. There is also a white led light that flashes SOS.

AIS, AIS/DSC, EPIRBs and PLBs will all have either a strobing white light or a white light flashing SOS.

Which leads us to the DSC distress alert on the Radio. Here you can send a digital distress alert and follow this with a voice message. The distress alert should be acknowledged digitally by a coast station and the voice call should get a voice response.

We have 3 transmission areas to consider (well 4 if you include 70ºN and S – the poles) and 3 types of radio to cover these.

Sea Area 1 covered by VHF radio, Sea Area 2 covered by MF radio and Sea Areas 3 and 4 covered by HG radio.

VHF (Very High Frequency from 300mHz – 3000mHz) is line of site and generally has a maximum range of 60 miles, although range depends on height or aerial and power of transmitter. This is what we use when sailing in coastal waters or when communicating ship to ship at sea with a vessel we can see, or indeed a rescuer.

MF (Medium Frequency from 300kHz – 3000kHz or 3mHz) transmissions follow the curvature of the earth and range depends again on height of aerial and power of transmitter, but range is generally up to 300 miles.

HF (High Frequency from 3mHz – 30mHz) transmissions are bounced off the ionosphere and travel thousands of miles, globally in effect. Their range is affected by the time of day of the transmission. The highest frequencies should be used at midday and the lowest frequencies should be used at night.

Icom 803 combining MF/HF and SSB Single Side Band radio

The Mayday Procedure

This is essentially the same for all 3 radios, with a couple of tweaks.

First we send the DSC Distress alert:

On VHF radios this is sent down Channel 70 (156.525mHz), the data channel.

On MF radios this is sent on 2187.50kHz.

On HF radios this is sent on one of five frequencies (see the Ready Reckoner table further down this report) depending on time of day.

In fact radios today combine the MF and HF into one unit with Single Side Band and there are 6 distress frequencies available. You would choose the most suitable one. In area 2 you would choose MF 2187.50kHz, in area 3 any of the other 5 – which are HF.

You can send on all 6 MF/HF frequencies but this can take time to get the DSC message out. It is best to send on one frequency.

Radios will allow you to choose your distress. The procedure is slightly different from radio to radio, so read the manual. Generally you lift the lid for the DSC Distress button and press it once. Or you can do this from within the radio on screen. You are then offered a choice of misery, anything from Fire, Flooding, Collision, Grounding, Capsizing, Sinking, Adrift, Abandoning, Piracy, MOB, or Undesignated. If you don’t select one of the choices then the alert will be undesignated.

Given that we are in grave and imminent danger requiring immediate assistance at the point of calling a Mayday, I think it is something of a distraction to have to choose. Picture it. A member of crew down below at the nav station shouts up to the skipper, “Are we sinking or capsizing?” ‘What? Never mind that just press and hold the distress button!’

Because if you just press and hold the distress button it will count down the seconds and the distress alert will be sent. On my Standard Horizon VHF radio it counts down from 5 secs, ‘One’, ‘Two’, ‘Three’, ‘Four’ and sends the signal on ‘Five’. So, if you have children with inquisitive fingers on board you have four seconds to get their finger off the button before the distress alert is sent. Actually, that’s three seconds because the first second has gone when you were first alerted that someone was pressing the distress alert button!

Going back to telling a potential rescuer the distress you have, it does make sense to me to alert them to ‘Piracy’. If you are about to be boarded by some fearsome individuals who are waving guns at you it would be a good idea to let the rescue centre know this. And so if they are trying to contact you on the radio and you are not answering it may not be that you are playing hard to get but that someone is pointing a gun at your head and you cannot speak to the rescuer.

So, we have sent the Distress Alert. We will get a digital acknowledgement within seconds, almost immediately.

In any event, acknowledgement or not, we send, about 15 seconds after the digital alert, the voice message.

What information does the DSC Distress alert contain?

Assuming that your radio either has GPS within it or it is connected to your GPS (and it should be) then the DSC distress Alert will contain your:

  • MMSI No. (Maritime Mobile Service Identity, a 9 digit code that is specific to your ship radio/vessel). The first 3 digits (MID Maritime Identification Digits) identify your nationality (e.g. UK 232/233/234/235)
  • Time the alert was sent
  • Position when the alert was sent

If for some reason your radio and the GPS are not linked then you need to put your time and position into the radio manually every hour. The radio will not advance the time or the position, but at least you will never be more than an hour’s worth of travel from the last recorded position in the radio.

What will the MRCC be doing with the information in the DSC?

Using the MMSI No. they will look up the vessel and have a good idea of your safety equipment, the colour and type of the liferaft if you decide to take to this. They may also look at the CG66 form, which was an old coastguard system of vessel identification before the MMSI No. They will locate your vessel by the Call Sign.

Which voice channel do you use?

It depends on what sort of radio you are using.

On VHF Radios the voice message is sent on Channel 16. The radio will have been switched to Channel 16 at high power (25 watts) the minute you sent the distress Alert.

On MF Radios, the voice message is sent on 2182kHz.

On HF Radios the voice message is sent on the most appropriate frequency for the time of day – highest frequency midday, lowest frequency night time. This should be written beside the radio. It may be best to list a middle frequency – 8414.5kHz – for the DSC alert and 8291kHz for the voice message, because if someone is calling a Mayday they may very well be in a state of panic.

Ready Reckoner for channels and frequencies:

If in doubt on HF use 8414.5kHz for the DSC Distress alert and 8291kHz for the voice.

What are we going to say?

There is a sensible and logical structure to this. Here is your chance to get across to a rescuer in 90 seconds all the detail they will need to mount the fastest, most effective rescue of you.

We have an acronym for this:


M Mayday
I Identify yourself
Pause for a moment to allow anyone listening to get a pen and paper
R Repeat
P Position
D Distress
A Assistance required
N Number of persons on board
I Any other Information
O Over

M – We say the Mayday three times – Mayday, Mayday, Mayday

I – We identify ourselves
This is…yacht/motor vessel/cruise liner/fishing vessel (say what type  of vessel we are as this gives the rescuer a clue as to what size of pump we will need, for example)… and our name three times, Wave Rider, Wave Rider, Wave Rider.
We read out our MMSI number first – they have just seen this come up on their screens as our MMSI number, time and position were sent  with the DSC Distress alert.
We read out our Call Sign. If you know the phonetic alphabet – use it.

We pause for a moment to allow any rescuer to get a pen and paper.

R – We repeat, Identify, type of vessel, name once, MMSI and Call Sign.

P – We read out our position using the radio terminology latitude first and then longitude. For example – 40º13’.5N by 020º15’.5W – is read as: four zero degrees, one three decimal five minutes north – by – zero two zero degrees one five decimal five minutes west.
There can be no confusion between thirteen and thirty or fifteen and fifty.

You can add in a distance and bearing to a known point.

Or if you have a mobile signal or wifi and thus data availability for your phone you can give a rescuer the ‘what3words’ for your position*.

D – The nature of your distress.

A – I require immediate assistance (it isn’t a Mayday if you don’t require immediate assistance).

N – Number of persons on board. Not number of crew. If you have a man overboard, then ‘Four persons on board one man in the water’, is fine.

I – Any other useful information, such as we are taking to the liferaft in 5 minutes. Now the rescuers know they are no longer looking for the boat but for for a liferaft.

O – Over

*what3words are multi language when ashore, but only available in English and Korean when at sea.

Man Overboard Scenario – Mayday Voice Call

Let us say you are a yacht – Fairwind MMSI No 235086183 Call Sign GION6. A member of the crew has gone overboard and you are trying to get back to him – man overboard is always a case for a Distress Call and a Mayday. There are two adults and three children on board and there is one man in the water. You are in the Solent. This is how the voice call would go…
You say…

  • M – Mayday, Mayday, Mayday
  • I – This is Yacht Fairwind, Fairwind, Fairwind, MMSI No 235086183, Call Sign Golf India Oscar November Six
  • Slight pause to allow everyone who is listening to get a pencil and paper to write down the details
  • R – Mayday this is Yacht Fairwind. MMSI No 235086183. Call Sign Golf India Oscar November Six
  • P – In position 50°47’.2N by 001°17’.5W
  • D – We have a Man Overboard
  • A – We require immediate assistance
  • N – There are 5 persons on board – and one man in the water
  • I  – We have the man in sight. His lifejacket has inflated and we are tracking him with his AIS beacon. We are trying to get back to him
  • O – Over

They will then come back to you and tell you how they plan to help you recover the man overboard.

You will have given them the best information you can to ensure that they can mount an efficient and speedy rescue.

Always have the Distress Alert procedure and MIRPDANIO written out by the radio. It will help to guide you if you are in a panic.

Finally, there is always the mobile phone and a 999 call, or a call to the coastguard to alert them directly to your distress, if you have signal.

And if you are mid Atlantic you have the Satellite Phone. You can’t call 999 on a Sat Phone but you could call the coastguard on their landline to alert them.


Other MOB Articles by Duncan Wells:



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About the Author:

Duncan Wells is an RYA instructor and features writer for Yachting Monthly, Sailing Today & Practical Boat Owner and author of Stress Free Sailing, Stress Free Motorboating and Stress Free Navigation. Duncan runs an RYA recognised training centre in Bucks, UK and also created the MOB Life Saver.


Other INSIGHTS can be found here.


Related Links:

A poorly executed mayday call from a yacht in New Zealand had Search and Rescue looking in the wrong area. To make matters worse the boat made it safely back to harbor but didn’t cancel the mayday. See report at RNZ News (23 Feb, 2021).


The opinions expressed in this article are the author’s own and do not reflect the view of or World Cruising Club.

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