VHF Radio Operation for Sailors - Mayday & DSC Basics

Prerequisites

This lesson is part of the RYA Competent Crew course (minimum age 16, no previous experience needed). Before starting you should:

• Have completed the yacht's safety brief, including where the VHF radio, handheld VHF and flares are kept.
• Understand basic boat terminology and the idea of position as latitude and longitude (from the Charts, Buoys and Compass lesson).
• Know the man overboard procedure and the basic emergency equipment on board (from the safety lessons).

Competent Crew does not qualify you to operate a marine radio on your own. In the UK the person using a VHF must hold an operator's certificate, normally the RYA/Ofcom Short Range Certificate (SRC), or be under the direct supervision of someone who does. The yacht must also have an Ofcom Ship Radio Licence. In a genuine emergency, anyone may and should use the radio to call for help. That is why every crew member needs to know how to send a Mayday, and why the RYA practical course notes list "VHF DSC operation and how to send a Mayday" as a compulsory part of every safety briefing.

Learning Objectives

By the end of this lesson you should be able to:

• Identify the main controls of a fixed and handheld VHF/DSC radio, and set them up ready to transmit.
• Explain the use of Channel 16 and of working, port and marina channels, and why Channel 16 must be kept clear.
• State the basic radio rules a crew member must respect: identification, no chatter, secrecy, who may transmit.
• Use the phonetic alphabet and number pronunciation and the standard procedure words.
• Give a position in the two forms used on the radio.
• Recognise the three priority messages: Mayday, Pan-Pan and Securite, and know when each is used.
• Send a DSC distress alert and a voice Mayday call in the correct format, using the procedure card by the set.
• Cancel a false alert.
• Understand the limitations of mobile phones as a backup.
• Estimate VHF range from aerial height, and carry out a radio check.
• Respond correctly if you hear a Mayday, and describe a Mayday Relay.
• Recognise the EPIRB, PLB, SART and NAVTEX and explain what each does.
• Use the sound signals and hand signals used on board and between vessels.

These map to the RYA Competent Crew syllabus items "Emergency communications: how to send a distress call on VHF" (under Safety and emergency equipment, with "Distress signalling: flares, VHF radio basics") and "Communication on board: signals and calls between helm and crew". The lesson also gives the background that the RYA Short Range Certificate (SRC) course builds on, which is the next step for anyone who wants to use the radio routinely.

Exam-style tip: on a Competent Crew course the instructor will usually ask each student to explain, or show on the radio, the Mayday call order. They are looking for position early, clear speech, the right order, and a calm voice. They are not looking for perfect recall of every detail, so use the call card and read from it.

How Marine VHF Works

Marine VHF (very high frequency) radio uses 59 international channels between 156 and 174 MHz, shared by hundreds of thousands of users. VHF travels in straight lines, so range depends on the height of the aerials: roughly line of sight. A yacht with a masthead aerial can expect about 20 to 30 miles to a coastguard station with a high aerial, but only 5 to 10 miles to another yacht. A handheld VHF at deck level may only reach 3 to 5 miles. Hills and headlands block signals.

Unlike a phone, a VHF broadcast is heard by everyone within range on that channel: the coastguard, lifeboats, ships and other yachts. That is its great strength in an emergency, because the nearest vessel may be able to help in minutes. It also means that every transmission is public and that only one station can talk on a channel at a time. Small-craft sets are simplex: you either transmit or receive, never both, and the press-to-talk switch changes the set from one to the other.

Working out the range

A useful rule of thumb for the radio horizon is about 2.2 times the square root of the aerial height in metres, giving a distance in nautical miles. The range between two stations is the sum of the two figures. This is a little better than the visual horizon because radio waves bend slightly towards the earth.

Worked example: your masthead aerial is 12 m above the water and the coastguard aerial is on a hill 100 m high. The theoretical range is about 7.5 + 22 = 29.5 nm. Two yachts with 12 m aerials can expect about 7.5 + 7.5 = 15 nm in theory, and a handheld to a yacht about 3 + 7.5 = 10 nm. In practice the figures are lower if the aerial cable is poor, the aerial is not vertical, or a headland is in the way. This is also why a call you hear clearly at the top of the tide may be lost when you drop behind a cliff. Sailing yachts use a short "unity gain" aerial that keeps working when the boat heels; the longer "high gain" aerials on motor boats give more range but only while they stay upright.

Two practical points follow. First, if you cannot raise a station, moving to a higher position (for example, standing in the cockpit with a handheld rather than sitting below) or switching to high power (25 W) may help. Second, a transmission that the coastguard cannot hear may well be heard by a ship 10 miles away, which is why you always keep calling in a distress. The mast is the aerial's support: if the yacht is dismasted the fixed set loses most of its range, which is one reason every yacht should carry a handheld.

The controls

The diagram below shows the controls found on most fixed DSC radios. Handheld radios have the same functions.

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Setting up to transmit: switch on, turn the volume up, set the squelch so the hiss just stops, select low power unless the station is far away, select the channel, and listen before pressing the button.

Microphone technique: hold the microphone about 8 cm from your mouth, slightly to one side. Press the PTT, wait a moment, then speak clearly at normal conversation level, a little slower than usual and without letting your voice drop at the end of a phrase. Release when you finish. Shield the microphone from wind with your body or hand. Anything the other station has to write down, such as a position, should be said very slowly: people can read 250 words a minute but write only about 20.

Channels

Channel 16

Channel 16 (156.800 MHz) is the international distress, safety and calling channel. HM Coastguard and all vessels at sea keep watch on it. The diagram below summarises the rules.

• Keep a listening watch on 16 whenever the radio is on and you are not using another channel.
• Use 16 only for distress, urgency and safety messages and for brief initial calls to establish contact. Then move to a working channel.
• No chat, music, or long conversations. Anything other than a distress call on 16 should be finished in under a minute.
• Listen before you transmit, so you do not interrupt someone else, especially an emergency.

Other channels you will use

The Reeds Nautical Almanac lists the channels for every port and marina. Channel 9 is used by many European marinas and by pilots in some UK harbours. Always use the channels listed for the area you are in. Marinas and yacht clubs are not allowed to use Channel 16, so you call them directly on their own channel.

The Rules

A radio is not a phone, and a crew member who picks up the microphone is bound by the same international rules as a ship's officer. The ones that matter most:

• Identify yourself every time you transmit, with the boat's name. Transmissions without identification are forbidden, and so is using your own name instead of the boat's.
• No chatter. Everything said on the radio should concern the safety or movement of vessels. Unnecessary transmissions, music, whistling into the microphone and bad language are all offences. Use the mobile phone to arrange supper with the boat two berths down.
• Only under supervision. Crew may use the radio under the supervision of the certificate holder, and every transmission must be authorised by the skipper. The exception is distress: in an emergency anyone may send a Mayday.
• Secrecy of correspondence. If you overhear a conversation on the radio you must not pass it on, or even mention that it took place.
• Never make a false distress call, even as a joke. It is a criminal offence and puts rescuers' lives at risk.
• Stay on watch after a distress. A boat involved in a rescue must not switch the radio off until the Coastguard stands it down.
• Use the licensed channels only, and only the UK ones in UK waters.

Talking on the Radio

The phonetic alphabet

Letters are easy to mishear over a radio. The international phonetic alphabet gives each letter a distinct word. The diagram below shows it, with the correct pronunciation of numbers.

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Numbers are spoken digit by digit: 156 is "wun fife six"; position 50 degrees 22.4 minutes north is "fife zero degrees too too decimal fow-er minutes north". Times are given in the 24-hour clock: 1425 is "wun fow-er too fife". Use the phonetic alphabet to spell the boat's name or any word that could be misunderstood, saying "I spell" first and the word again afterwards: "Yacht Ocean Star, I spell: Oscar Charlie Echo Alfa November, Sierra Tango Alfa Romeo, Ocean Star."

Procedure words

Giving a position

Rescuers need your position before anything else, and there are only two correct ways to give it:

• Latitude and longitude, read from the GPS or chart plotter digit by digit: "five zero degrees one two decimal four minutes north, zero zero one degrees two seven decimal seven minutes west."
• A true bearing and distance FROM a charted object: "one eight zero degrees from Portland Bill lighthouse, two decimal four miles." The bearing is from the lighthouse to you, not from you to the lighthouse, and it is in degrees true, as on the chart.

Plain words ("two miles south of Anvil Point") are acceptable in an emergency if that is all you can manage; "we're near the big cliff" is not.

A routine call

To call another station:

1. Listen on 16 (or the appropriate channel) to make sure it is clear.
2. Press PTT: "Seabird, Seabird, this is Ocean Star, Ocean Star, channel seven two, over." (Name of the station called, up to three times, then your name, up to three times; twice each is usual in good conditions. Proposing the working channel in the first call gets you off 16 sooner.)
3. They reply: "Ocean Star, this is Seabird. Seven two, over."
4. Both switch to 72, and you call again there: "Seabird, this is Ocean Star on seven two, over."
5. Hold your conversation briefly, then finish with "Seabird, this is Ocean Star, out." Return to Channel 16.

Calling a marina is similar but direct on the marina channel, with the marina's name said once because they are listening for calls: "Haslar Marina, this is yacht Ocean Star, Ocean Star, over." State what you need clearly: "We are a 36-foot sailing yacht, draught 1.8 metres, requesting a berth for one night, arriving in about 30 minutes, over." Read back the berth number they give you.

If nobody answers, check your own set first (volume, squelch, channel, power, and that the button is not stuck), then wait at least two minutes before calling again. If another boat has not answered after two calls, it is not listening; stop calling and try later.

Radio checks and DSC routine calls

Before you rely on a radio, check it works. Do not ask the coastguard for a radio check on Channel 16. Instead:

1. Choose a working channel suitable for the area (for example Channel 72 or 6 ship to ship, or the marina channel).
2. Call a nearby marina or another yacht: "Haslar Marina, this is yacht Ocean Star, Ocean Star, radio check on Channel 80, over."
3. The reply gives a strength and clarity report in words: "loud and clear", "readable but weak", "unreadable". Some marinas offer a radio check service; in the UK, an automated radio check is available on a published channel in some areas (see the almanac). A test call must last no more than 10 seconds.

Modern DSC sets can also make a routine individual call to another vessel's MMSI, much as you would dial a phone number. The call rings the other radio, and if the other skipper accepts, both radios switch automatically to an agreed working channel, so you never need to call on 16. You can also use DSC to send an all-ships safety or urgency call, and a DSC test call to the Coastguard to prove the system works. DSC calls always go out on Channel 70; you never speak on 70.

Each radio's MMSI (Maritime Mobile Service Identity) is a nine-digit number. In the UK a boat's MMSI begins with 232, 233, 234 or 235; a coast station's begins with two zeros. It is linked to the boat's Ship Radio Licence. A handheld DSC radio may have its own MMSI, and you should know which number is programmed into which set on your boat. A fixed set with no MMSI entered cannot send a DSC distress alert.

Receiving a Mayday

You may be the nearest vessel, or one of many that hear a Mayday. The correct response matters.

1. Stop all non-essential transmissions. Keep the radio on Channel 16 and listen.
2. Write down the details: the name and MMSI of the vessel, the position, the nature of the distress, the assistance required and the number of people on board. Use the pad kept at the radio.
3. Tell your skipper at once. The skipper decides whether to go to help.
4. Do not reply at once if the coastguard is likely to hear it: HM Coastguard will normally acknowledge ("Mayday ... this is Solent Coastguard, received Mayday"). If a short time passes, perhaps a few minutes, and nobody has acknowledged, and you are in a position to help, the skipper may acknowledge: "Mayday, Ocean Star, this is Seabird, received Mayday." Acknowledging commits you to go and help.
5. If the vessel in distress is out of range of any shore station, you can transmit a Mayday Relay (see below).
6. Record what you heard, and when, in the ship's log.

The coastguard, or the station in control of the distress, may impose Seelonce Mayday to tell all other stations to keep off the channel. When the emergency is over the coastguard sends "Mayday, all stations, ... Seelonce Feenee". Until you hear that, do not use Channel 16 for anything else.

The Mayday Relay

A Mayday Relay is sent when you hear a distress call that nobody acknowledges, or when you know that another vessel is in distress and cannot send a call: you see red flares, a boat on fire, or a person on a capsized dinghy raising and lowering their outstretched arms. It is a duty of every vessel. The format is:

"MAYDAY RELAY, MAYDAY RELAY, MAYDAY RELAY. All stations, all stations, all stations. This is Seabird, Seabird, Seabird. Received from yacht Ocean Star at 1425 UTC: [the details of the original Mayday in the order given]. Over."

Make it quite clear that you are not the casualty, otherwise a lifeboat may take a bearing on your transmission and go to the wrong place. On a DSC set the skipper sends an urgency alert first (not a distress alert, because your boat is not in distress) to wake the other sets, then the voice relay. Do not use a relay if the coastguard has already acknowledged: needless repeats clutter the channel.

Pan-Pan Medico and medical advice

For a medical problem that is serious but not immediately life-threatening, the coastguard can connect you to a doctor who gives advice by radio or phone. Call "PAN-PAN, PAN-PAN, PAN-PAN. All stations ... require medical advice" on 16, or use a DSC urgency call, and then go to the working channel that the coastguard selects. Be ready to give the patient's age, sex, symptoms, pulse and breathing, what has happened, and what you have given. If the person is unconscious, not breathing or bleeding heavily, this is a Mayday.

Other GMDSS Equipment Every Crew Member Should Recognise

VHF/DSC is one part of the Global Maritime Distress and Safety System (GMDSS), the worldwide system that ensures a casualty can alert the rescue services by two independent means. A UK yacht sailing within about 20 to 30 miles of the coast (Sea Area A1) normally relies on VHF/DSC, but you should also know the other equipment:

• EPIRB (Emergency Position-Indicating Radio Beacon). A 406 MHz beacon, registered to the boat, which sends a satellite distress signal with a unique ID and a GPS position when activated, either automatically when floated free or by hand. It transmits for at least 48 hours, and a 121.5 MHz homing signal lets the lifeboat find it in the last mile.
• PLB (Personal Locator Beacon). A smaller version carried by a person, for example in a lifejacket pocket. It is registered to the person and works anywhere, but must be held clear of the water.
• SART or AIS-SART. A radar transponder or AIS transmitter taken into the liferaft that makes the raft show on a ship's radar (as a line of dots) or AIS display. It is held as high as possible.
• Personal AIS beacons fitted to lifejackets that alert the boat's own AIS and chart plotter if you fall overboard.
• NAVTEX. A small receiver near the chart table that prints or displays weather forecasts, gale warnings and navigational warnings sent by coast stations, out to about 300 miles. It receives only; it cannot be used to call anyone.

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Image: Marwan Mohamad.jpg), CC BY-SA 4.0, via Wikimedia Commons.jpg)

An accidentally activated EPIRB must be reported: do not switch it off until you have told the coastguard, giving the position and the beacon's identity, and they say you may. A beacon that goes silent before the rescue centre knows it was a mistake can keep a search going for hours. Check the beacon's registration and battery expiry date before every season.

Licensing and the Rules in the UK

In the UK, using a marine VHF needs three things. Competent Crew candidates are not expected to hold the first two, but they should understand them.

The one exception is distress: anyone may use the radio to send a Mayday. A skipper who needs to train a crew should have at least one qualified person aboard, and many skippers will not let an unqualified person talk on the radio except in an emergency.

Priority Messages

There are three levels of priority message. They take precedence over all other traffic, in this order: Mayday > Pan-Pan > Securite.

Mayday: distress

A Mayday is used only when a vessel, aircraft or person is in grave and imminent danger and requires immediate assistance. Examples:

• The boat is sinking or there is a fire out of control.
• A crew member has gone overboard and cannot be immediately recovered (UK coastguard advice is to send a Mayday for man overboard).
• A life-threatening injury or illness (unconscious, not breathing, heart attack, heavy bleeding).
• The boat is about to be wrecked on a lee shore with no means of escape.

A dismasting with no one hurt and no immediate danger, or an engine failure in open water, is not a Mayday: it may be a Pan-Pan. The word Mayday is never spoken on the radio except in a real distress, not even in conversation.

DSC distress alert

Modern VHF radios have Digital Selective Calling (DSC). Each radio has a nine-digit MMSI (Maritime Mobile Service Identity) number registered to the boat. When you press and hold the red DSC distress button, the radio sends a digital alert on Channel 70 to every DSC station in range, containing the MMSI, and, if the radio is connected to a GPS, the boat's position and time. Receiving radios sound an alarm and switch to 16. The coastguard immediately knows who you are and, ideally, where you are.

To send a basic DSC distress alert:

1. Check the main battery switch and the radio are on.
2. Lift the cover over the red DISTRESS button and press it once.
3. If there is time, select the nature of distress from the menu (fire, flooding, collision, grounding, capsizing, sinking, disabled and adrift, abandoning ship, man overboard, piracy, undesignated).
4. Press and hold the button for about 5 seconds until the radio confirms the alert has been sent.
5. The radio automatically switches to Channel 16. Wait about 15 seconds for an acknowledgement, then send the voice Mayday.

The alert is repeated automatically about every 4 minutes until it is acknowledged by a coast station. If the set has no position, the alert still goes, but you must give the position by voice.

The voice Mayday

The diagram below shows the structure of a Mayday call. Learn it so well that you can say it under stress.

The full UK format (used by HM Coastguard and taught on the SRC course) is:

1. MAYDAY, MAYDAY, MAYDAY
2. THIS IS [boat name three times], [MMSI, or call sign if the set has no DSC]
3. MAYDAY [boat name once]
4. MY POSITION IS [latitude and longitude, or a true bearing and distance from a charted point, for example "one eight zero degrees from Anvil Point, two miles"]
5. NATURE OF DISTRESS: what is happening, for example "we are on fire" or "we are sinking"
6. ASSISTANCE REQUIRED: "I require immediate assistance"
7. NUMBER OF PERSONS ON BOARD
8. ANY OTHER INFORMATION: for example "abandoning to liferaft", "one crew injured", boat description, "we have flares"
9. OVER

Release the PTT and listen. The procedure card for the boat's radio, usually fixed next to it, has this format with the boat's name, call sign and MMSI already filled in. Find it now on your boat. The RYA recommends every boat displays one, with a version for sets with DSC and a version for sets without.

The position is the most important part. A latitude and longitude from the GPS or chart plotter is best; a bearing and distance from a well-known landmark is fine. If you have time, give it before the details: rescuers can start moving as soon as they know where you are.

Worked Example: Mayday

The yacht Ocean Star has struck a submerged object and is taking water faster than the pumps can clear it. The skipper is organising the crew and asks you to send a Mayday. The diagram below shows the sequence you follow.

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1. You lift the cover and hold the red DSC button for 5 seconds. The display shows "Distress alert sent".
2. The radio is now on Channel 16. You check the volume is up, the squelch is just closed and high power is selected. You read the position from the plotter: 50 22.0N 001 45.0W.
3. You press the PTT and say, slowly:

"MAYDAY, MAYDAY, MAYDAY. This is yacht Ocean Star, Ocean Star, Ocean Star, MMSI two three five zero one two three four five. MAYDAY Ocean Star. My position is fife zero degrees two two decimal zero minutes north, zero zero wun degree fow-er fife decimal zero minutes west. Struck submerged object, holed and sinking. I require immediate assistance. Four persons on board. Preparing to abandon to liferaft. Over."

1. You release the PTT and listen. Solent Coastguard replies: "Mayday, Ocean Star, Ocean Star, Ocean Star, this is Solent Coastguard, Solent Coastguard, Solent Coastguard, received Mayday." They ask questions; answer briefly. They may tell you that a lifeboat is on its way and ask you to keep listening on 16.
2. If there is no reply within about 30 seconds, repeat the call. Keep trying; a nearby vessel may relay your Mayday (a Mayday Relay) even if the coastguard cannot hear you directly.
3. If you abandon to the liferaft, take the handheld VHF with you, clipped on, and keep it on Channel 16.

Pan-Pan: urgency

Pan-Pan (pronounced "pahn-pahn") is used when there is an urgent problem concerning the safety of a vessel or person, but the danger is not grave and imminent. Examples:

• Engine failure near a lee shore or in a shipping lane, with no immediate danger.
• Dismasting or rudder failure with no one injured and the boat not in immediate danger.
• A crew member with an injury or illness needing medical advice or evacuation but not life-threatening at present (a Pan-Pan Medico for medical advice).
• Being lost or short of fuel in deteriorating weather.
• Taking on water, but the pumps are keeping up.

The format follows the same pattern as a Mayday: "PAN-PAN, PAN-PAN, PAN-PAN. All stations, all stations, all stations. This is [name three times], MMSI. My position is... [nature of the problem], [assistance required], [persons on board], over." It can be preceded by a DSC urgency alert, which is sent from the menu with the ENTER button, never with the red distress button. A DSC urgency alert carries no position, so the voice message must give it. If the situation gets worse, upgrade to a Mayday immediately.

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Worked Example: Pan-Pan

The yacht Ocean Star has lost her engine in a flat calm, drifting slowly towards a rocky headland 1.5 miles away in a rising tide. There is no wind to sail away. Nobody is hurt, but the drift will bring her onto the rocks in about two hours.

"PAN-PAN, PAN-PAN, PAN-PAN. All stations, all stations, all stations. This is yacht Ocean Star, Ocean Star, Ocean Star, MMSI two three five zero one two three four five. My position is two two five degrees from Anvil Point, wun decimal fife miles. Engine failed, drifting towards the shore in a flat calm. I require a tow. Four persons on board. Anchor ready to deploy. Over."

Solent Coastguard replies and asks for the water depth and the time estimate to the rocks. The crew drop the anchor to hold position, and a lifeboat is launched. The skipper cancels nothing: the Pan-Pan stays active until the lifeboat is alongside, and is then cancelled with an all-stations call. Had the anchor not held and the boat started to be swept onto the rocks, the skipper would have upgraded to a Mayday.

Worked Example: Cancelling a false alert

A crew member knocks the DSC distress button with a winch handle and holds it for six seconds. The display flashes "Distress alert sent". The crew member cancels the alert from the DSC menu (on an older set the skipper switches the DSC off and on again to stop the repeats), then the skipper calls on 16:

"All stations, all stations, all stations. This is yacht Ocean Star, Ocean Star, Ocean Star, MMSI two three five zero one two three four five. Position fife zero degrees two two minutes north, zero zero wun degrees four fife minutes west. Distress alert sent in error. Cancel my distress alert of one four two five UTC. Out."

The coastguard replies and takes details, and the skipper confirms they have received the cancellation. No further action is needed, and there is no penalty for an honest, promptly cancelled mistake.

Securite: safety

Securite (pronounced "say-cure-ee-tay") introduces a navigational or weather warning for all stations. The diagram below shows typical uses and the format.

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You will hear the coastguard use it on Channel 16 to announce Maritime Safety Information broadcasts: "Securite, Securite, Securite. All stations, all stations, all stations. This is Solent Coastguard. For gale warning and navigational warnings, listen on Channel 6 3." The message itself is read on the working channel, not on 16. A yacht might send one to warn others of a large floating hazard, such as a container, or because it is towing a disabled vessel across a channel.

False alerts

If the DSC distress button is pressed accidentally, cancel it immediately:

1. Cancel the DSC alert using the radio menu if possible, or switch the DSC off briefly to stop the repeats, then back on.
2. Go to Channel 16 and say: "All stations, all stations, all stations. This is [name three times], MMSI, position. Distress alert sent in error. Cancel my distress alert of [time] UTC. Out."
3. Make sure the coastguard has heard the cancellation.

There is no penalty for an honest mistake that is cancelled. Knowingly sending a false distress call is a criminal offence and puts rescuers at risk.

Mobile Phones as a Backup

A mobile phone is a useful backup, but no substitute for VHF. The diagram below compares them.

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• In the UK dial 999 or 112 and ask for the Coastguard.
• Mobile coverage is patchy along cliffs and disappears a few miles offshore.
• A phone call reaches only one person; nearby vessels that could help in minutes will not hear you.
• Rescuers cannot home in on a phone call the way they can on a VHF transmission, and you cannot hear broadcast warnings on it.
• Keep the phone fully charged in a waterproof case, with the coastguard number saved.

The RYA SafeTrx app lets you log passage plans and contacts with the coastguard, and can alert your emergency contact if you are overdue. It is a useful supplement, not a replacement for VHF and a passage plan left with someone ashore. The coastguard will not start a search for an overdue yacht unless somebody ashore reports it overdue, so every passage needs a shore contact who knows the plan.

Sound Signals

Vessels in sight of one another use whistle or horn signals to show what they are doing (COLREGs Rule 34). A short blast is about 1 second; a prolonged blast is 4 to 6 seconds. The diagram below summarises the signals you are most likely to hear.

A big ship sounding five short blasts at you means "get out of my way now". In fog there are different signals (for example a power-driven vessel making way sounds one prolonged blast at least every 2 minutes, and a sailing vessel one prolonged and two short); these are covered in the Introduction to the Collision Regulations lesson.

Communication On Board: Hand Signals

On a yacht, the helm in the cockpit often cannot hear the crew on the foredeck, especially when the engine is running, when anchoring, or when picking up a mooring. Agree hand signals before you start. The four diagrams below show a common set.

Other signals commonly used:

• Point at the buoy, mooring or anchor chain continuously so the helm knows where it is when it disappears under the bow.
• Thumb up = go ahead / anchor has bitten / all fast. Thumb down or hand flat across the throat = stop the engine or neutral.
• Numbers of fingers = distance to go in boat lengths or metres, or amount of chain let out (for example 5 fingers = 5 metres more).

The foredeck crew points in the direction the helm should go, not at the object, unless agreed otherwise. Agree which method you use before the manoeuvre.

Hand signals when anchoring or picking up a mooring: a procedure

1. Before the manoeuvre, the skipper briefs the crew on the plan and the signals. The foredeck crew repeat them back.
2. The foredeck crew stand on the foredeck in a position where they can be seen from the helm, with a boathook ready and, for a mooring, the pick-up line prepared.
3. The foredeck crew point to the mooring buoy as soon as they see it and keep pointing as the boat approaches.
4. A flat palm held up means stop or neutral. If the helm does not respond at once, the signal is repeated with both arms.
5. Once the buoy is secured, a thumb up or a clear call, "Made fast", tells the helm to put the engine in neutral.
6. If signals are not understood, the crew come aft to talk. Shouting does not help against the engine and wind.

Many incidents on yachts begin with a misunderstood signal on the foredeck. A foredeck crew member with a boathook in a rolling boat is at risk, and the helm must keep the boat under complete control.

Calls between helm and crew

The most important rule is closed-loop communication. When the skipper gives an instruction, the person it is for repeats it and then reports when it is done:

• Skipper: "Sam, ease the genoa sheet two feet."
• Sam: "Easing the genoa sheet two feet."
• Sam (when done): "Genoa sheet eased."

Use names, short sentences, and a clear voice. Standard calls on a yacht include "Ready about" (answered "Ready"), "Lee-ho" or "Helm's a-lee" when the helm puts the tiller over, "Gybe-ho" when the boom is about to cross, "Man overboard" (said loudly, with the pointing arm kept on the casualty) and "Fenders" when approaching a berth.

Common Mistakes

The diagram below summarises common radio mistakes and their fixes.

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• Talking over others. Always listen before pressing the PTT.
• Forgetting to release the PTT. While you hold it you block the channel and cannot hear replies. A stuck switch can block a channel for miles around.
• Omitting the position in a distress call. Without a position no one can help. Give it early and repeat it.
• Giving a bearing to the lighthouse instead of from it.
• Holding conversations on 16. Make contact, then change to a working channel.
• Saying "repeat" instead of "say again", or "over and out".
• Speaking too fast or shouting. Under stress, slow down deliberately. Shouting distorts the transmission.
• Not knowing where the radio is or how to switch it on. Check on day one; find the Mayday call card.
• Accidental DSC alert left uncancelled. Cancel immediately by voice on 16.
• Switching off an EPIRB that went off by accident before telling the coastguard.
• Relying on a mobile phone offshore. It may not work and nobody nearby will hear.
• Calling Mayday for a non-life-threatening problem. Use Pan-Pan; upgrade if it gets worse.

Safety Notes

• In any emergency, anyone may use the radio. Do not hesitate because you are not licensed.
• Keep a listening watch on Channel 16 at sea.
• Carry a waterproof handheld VHF, charged, to take into the liferaft.
• Check that the DSC radio has the MMSI programmed and a GPS connected; otherwise the alert will not include a position.
• Before leaving harbour, do a radio check with a marina or another vessel on a working channel (not the coastguard on 16).
• If you are going to sea regularly, take the SRC course: it is one day and covers DSC operation in detail.
• Keep the handheld in a waterproof pouch and charge it after every trip. A handheld has only about 5 W maximum power (usually 1 to 5 W), and its battery may last 8 to 10 hours.
• Do not transmit from under a hatch or below decks if you can avoid it: the signal will be weaker.
• Keep the procedure card visible at the radio, with the boat's name, call sign, MMSI, and the size of the boat filled in.
• Keep a pencil and a waterproof pad at the radio to write down a position or a message.
• When you are the one in trouble, do the most urgent things first: shout for help from the crew, get lifejackets on, send the alert, then talk. A DSC alert takes 5 seconds and goes out while you deal with the emergency.

Summary

• VHF reaches everyone in range, roughly line of sight; that makes it the best way to call for help at sea.
• Listen before transmitting, keep 16 for distress, safety and brief calls, and move to a working channel. Identify the boat every time, no chatter, no passing on what you overhear.
• Use the phonetic alphabet, digit-by-digit numbers and standard procedure words: over, out, say again, received.
• Give a position as latitude and longitude, or as a true bearing and distance from a charted object to you.
• Mayday = grave and imminent danger to life or vessel. Pan-Pan = urgent but not immediately life-threatening. Securite = safety warning. Mayday > Pan-Pan > Securite.
• In distress: hold the red DSC button for 5 seconds, wait 15 seconds, then send a voice Mayday on 16: Mayday x3, this is name x3 and MMSI, Mayday name, position, nature, assistance, persons on board, other information, over.
• If you hear a Mayday: write it down, tell the skipper, let the coastguard answer, relay if nobody does.
• Cancel an accidental alert immediately by voice; never send a false Mayday; never switch off a false EPIRB until told to.
• Mobile phones (999 or 112, ask for Coastguard) are a backup only.
• Know the basic whistle signals and agree hand signals with the helm before manoeuvres.

Check Your Understanding

1. What is Channel 16 used for, and what should you do after making contact with another station on it?

Answer: Distress, urgency, safety messages and brief initial calls. After making contact, agree a working channel and move to it, leaving 16 clear.

2. What is the difference between "over" and "out"?

Answer: "Over" means I have finished and expect a reply. "Out" means the conversation has ended and no reply is expected. They are never used together.

3. Give two situations that justify a Mayday and two that should be a Pan-Pan.

Answer: Mayday: the boat sinking, an uncontrolled fire, a person overboard who cannot be recovered, a life-threatening injury. Pan-Pan: engine failure with no immediate danger, a dismasting with no injury, a non-life-threatening medical problem needing advice.

4. What information does a DSC distress alert send automatically, and what does it need to include position?

Answer: The boat's MMSI (identity), the time and, if available, the position and nature of distress. The radio must be connected to a GPS (or have the position entered manually) to include the position.

5. Put the following parts of a Mayday call in order: persons on board, position, nature of distress, "Mayday Mayday Mayday", "This is" plus name three times, assistance required, over.

Answer: "Mayday Mayday Mayday"; "This is" plus name three times and MMSI (then Mayday plus name once); position; nature of distress; assistance required; persons on board; any other information; over.

6. How do you say the position 50 degrees 14.6 minutes North on the radio, and what is the other correct way of giving a position?

Answer: "Fife zero degrees wun fow-er decimal six minutes north." The other way is a true bearing and distance from a charted object to you, for example "one eight zero degrees from Portland Bill lighthouse, two miles."

7. You accidentally press the DSC distress button and an alert is sent. What should you do?

Answer: Cancel the alert on the radio (or switch the DSC off and on to stop the repeats), then on Channel 16 call "All stations" three times, give your name three times, MMSI and position, and say "Distress alert sent in error, cancel my distress alert of" the time, out. Confirm the coastguard has heard it.

8. Why is a mobile phone not a substitute for VHF at sea?

Answer: Coverage is limited offshore and under cliffs, a call reaches only one person so nearby vessels that could help do not hear it, rescuers cannot home in on it, you hear no broadcast warnings, and batteries go flat. Use 999 or 112 and ask for the Coastguard only as a backup.

9. A large ship near you sounds five or more short, rapid blasts. What does it mean?

Answer: The ship does not understand your intentions or doubts that you are taking enough action to avoid a collision. Take clear, early action to keep out of its way.

10. While picking up a mooring, the foredeck crew holds both arms up with palms forward. What does it mean, and why are hand signals used?

Answer: Stop. Hand signals are used because the helm often cannot hear the foredeck over the engine and wind, and the mooring is hidden under the bow.

11. You hear a Mayday from a yacht 12 miles away, and nobody acknowledges it. What should you do?

Answer: Write down the details, tell your skipper, wait a short time to see if the coastguard acknowledges, then if no one does, the skipper acknowledges by voice if you can help, or transmits a Mayday Relay on 16 giving the original details (on a DSC set, after an urgency alert). Do not relay if the coastguard has already acknowledged.

12. Your masthead aerial is 12 m high and the coastguard aerial is 100 m high. Roughly what range can you expect, and what would you do if you could not raise the station?

Answer: About 2.2 times root 12 plus 2.2 times root 100, which is roughly 7.5 plus 22, so about 29 to 30 nm. If you cannot raise them, check the squelch, volume, power (use 25 W) and the aerial connection, move away from any shelter, and keep trying, as other ships may hear you.

13. What do the letters EPIRB stand for, how does it differ from a PLB, and what do you do if one goes off by accident?

Answer: Emergency Position-Indicating Radio Beacon. An EPIRB is registered to the boat and is usually fixed to float free; a PLB is smaller, registered to a person, and carried on the body. Both send a 406 MHz satellite distress signal with a GPS position. If one is activated by accident, do not switch it off; tell the coastguard, giving your position and the beacon identity, and switch it off only when they say so.

14. Name three things that are forbidden on a marine VHF radio.

Answer: Any three of: transmitting without the boat's name, unnecessary chatter or music, bad language, false distress calls, passing on something overheard on the radio, using the set without the skipper's authority or without supervision by a certificate holder, and switching off before a distress is over.