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VHF & MMSI - Cruising Workshop

VHF & MMSI - Cruising Workshop

Welcome to this week's bonus lockdown cruising preparation workshop!

Island Cruising NZ runs regular comprehensive cruising preparation workshops to help our members prepare for long coastal or offshore voyages. This is an example of some of the content we provide to help you upskill and prepare you, your crew and your vessel to go sailing! If you'd like to access this and more of our member resources you can join Island Cruising for just $75.00 per annum, and also get all our other great member benefits and discounts too. You can join up here. 

Please feel free to share this information with your fellow sailors, or boaties who might need a refresh. 

So lets get started! How well do you know your VHF radio? 

Safety Regulations

The Safety Regulations state that for Cat 1, 2 & 3 your vessel needs to have an installed VHF Radio, a call sign and you need an operator's license.

You also need a waterproof hand held VHF Radio, and in addtion to this you need another one in your Grab Bag

So that is three VHF's in total. I like to take a handheld VHF when I go in the dinghy too, just in case the motor breaks down, or you need to radio back to the boat. Make sure they are well charged, and even if they say they are waterproof, I still like to carry mine in a light dry bag just in case. 

How do VHF Radios work?

VHF Radios work within line of sight - i.e the two aerials have to be visible to one another. They transmit Very High Frequency radio waves which travel in a straight line. If you are at sea, the curvature of the earth limits the communications between two vessels, but when you are close to shore, things like hills can prevent communications. Line of sight transmissions are called Simplex Operation.

Thankfully to prevent the hills from disrupting communications, along the coastline we have repeater stations positioned on hill tops which relay the messages on two separate frequencies. These are called Duplex Operations. Some of these repeaters are public and others may be owned by a radio association. You can pay a membership fee to use the private repeater channels and access the service they provide.

Messages transmitted via VHF are able to be heard by everyone in range listening on that particular channel. This is a good thing when there is an emergency, as your call goes out to everyone nearby. But it is worth remembering that everyone can hear your conversation, so make your transmissions short and sweet.

VHF Radios are either hand held or they are wired in to your boat's battery system. Hand held VHF Radios run on a battery and need to be charged up regularly. 

VHF radios have a High or Low power setting. You should always use the low power setting when you are in a harbour or close to the boats you are communicating with. Using low power saves battery life and reduces interference. 

The higher your aerial, the greater the range. If you are trying to communicate with someone in the distance, aim to have your aerial as high as possible, and change on to the high power setting.

You should also always select the 'international' setting if you have one. This is the correct channel/frequency combination for use around New Zealand. The USA & Canada setting will not work.

Your VHF will also have a scan or dual watch function. Most will allow you to save a number of channels to memory, so that when you hit the scan button, the radio will cycle through the stored channels and will stop when it hears a message. The Dual watch operates in the same way but will listen to both channel 16 and one other channel. 

Most modern VHF's will also have a DSC function and we will cover that off in more detail a little later on.

Maritime Radio

Maritime New Zealand operates a comprehensive VHF service around our coastline. The Maritime Radio team are based in Lower Hutt and you can go and visit them if you are keen to see how things work behind the scenes. (It is really interesting - make an appointment before you drop in). 

There are 30 stations around our coastline, but all the transmissions are made from their base in Lower Hutt. 

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Maritime Radio provides a 24 hour listening watch on channel 16, search & rescue communications, safety, weather and navigational warnings, weather forecasts at scheduled times, medical advice, trip reports and radio checks.

To contact Maritime Radio you simply call up on Channel 16 by using the name of the area you are in. So for example "Akaroa Maritime Radio, Akaroa Maritime Radio, Akaroa Maritime Radio, this is..." etc 

They will then reply and ask you to go to one of their working channels - 67, 68, 69 & 71, where you can then do your trip report, or you can ask them to test your radio transmission, request assistance and that kind of thing.

As you sail up the coast you change the name of the station you are calling. So when we sail from Lyttelton up to Picton we call Akaroa Maritime Radio to lodge the trip report, and then Picton Maritime Radio to end it when we arrive.

Other Service Providers

Coastguard provides a network of stations and repeater channels around the coastline and also on some lakes. 

Port Authorities operate their own radio services in their area.

Private Radio Stations are run by associations and provide services for recreational and commercial entities. Private Stations include:

Using the VHF - Getting a License

Having a Maritime VHF Radio Operator Certificate is a legal requirement for using a VHF radio (unless you’re making a distress call or calling about or responding to an emergency). Whether you use it for an emergency or not, you need to know how to use your VHF radio properly. Having a license is also a requirement if you are sailing offshore. 

Coastguard Boating Education offers the Maritime VHF Radio Operator Certificate courses in New Zealand. You can do a variety of different options:

Maritime VHF Operator’s Certificate (MVOC) - this is the basic VHF only course

Maritime Restricted Radiotelephone Operator Certificate (MRROC) - this one includes the use of HF or SSB radios as well

Maritime Short Range Operator’s Certificate (MSROC) - this one is a requirement for anyone wishing to operate a VHF radio in Europe, and a prerequisite for the RYA Yachtmaster Certificates of Competence.

If you haven't already got your VHF license, then what better time than now in lockdown to do it! You can do most of the course from home or online but then the exam is in person for MRROC & MSROC. If you are going to do one, I'd really recommend the MSROC. It is a bit more involved but it does mean you are already qualified if you are planning on doing any commercial qualifications or if you are going sailing in Europe.

A person who holds one/either of these certificates means they have sat and passed an exam to operate radio equipment specific to that type of maritime certificate. Maritime certificates of competency do not give any rights to transmit radio waves.

GURLs - General User Radio License & Maritime Ship License

MF/HF (SSB) and VHF marine radiotelephones installed on vessels are operated in New Zealand waters under the NZ General User Radio License for Maritime Purposes. This means that your vessel doesn't need to be individually licensed. 

Vessels travelling in overseas waters are not covered by the General User Radio Licence.  So when you leave New Zealand, you also require A Maritime Ship (radio) Licence. This consists of a licence number, a call sign number, an MMSI number and depending on the vessel type, a radio telex number. The Maritime Ship Licence is an individual radio licence granted to the owner of the vessel.

The licence is recorded in the online Register of Radio Frequencies (RRF) and is recognized by overseas administrations under agreements with the International Telecommunications Union (ITU). You can also get a printed copy of the license to file in your important documents. Having this license isn't a requirement for our NZ Safety Regulations, it is however a requirement if you are asked to present your Maritime Ship License to any overseas authorities who request it. 

You can download the application form here. 


Call Signs & MMSI

Once you’ve completed a VHF radio course you can get a call sign, which is unique to your boat and is a legal requirement for making a call on your VHF radio. In New Zealand, callsigns begin with the letters ZM followed by another letter and 4 numbers.

If you have a DSC capable radio, you'll also need a Maritime Mobile Service Identity (MMSI). This is a series of nine digits which are sent in digital form over a radio frequency channel in order to uniquely identify ship stations, coast stations, coast earth stations, and group calls. An MMSI, once entered into a radio transmitter or AIS equipment, is very difficult to remove, therefore it is highly recommended that the callsign and MMSI remain with the vessel. 

A call sign and MMSI belongs to a person. If you purchase a vessel, the call sign and MMSI does not automatically transfer over. Permission must be granted by the person who owns the call sign and MMSI to transfer it over to a new holder. 

There might be several boats in New Zealand with the same name as yours, so the call sign distinguishes your boat. The call sign is registered on the National Search and Rescue Database, which will include other information about your boat and emergency contact details that will make it easier to help you. If you sell your boat you can keep your call sign or let it go with the boat’s new owner.

The one-off cost is $50.

You can get a call sign, update your details and change ownership of call signs online here

The call sign database includes details of your emergency contact, the type, size and colour of your boat, what equipment you have aboard and other such details. It’s important you update your call sign details if you sell your boat or if any of your details (especially your emergency contacts) change.

Which Channel Should I Use?

Channel 16 is reserved as an initial calling channel and also for distress messages. You should monitor channel 16 when you are out at sea. If someone calls you on channel 16 you should respond and then change to a 'working channel'.

Inter-ship working channels are 6 & 8. You can talk to each other on these simplex channels if you are within line of sight of one another.

If you are needing to use a repeater channel, you should use the appropriate one for your area. It may be a private radio channel, and you may need to be a member of the association to use it for anything other than emergencies.

Yacht Clubs usually use channel 77 for calling their members for details of the racing course for the day and that kind of thing. 

Nowcasting - weather information is transmitted on channels 19, 20 & 79.

Marinas use channel 73. 

Maritime NZ use 67, 68, 69 & 71.

Do NOT use channel 70 as this is the channel that the DSC transmissions go through on. 

There are more details of the channels in the Maritime Radio Handbook. More details below.

Lodging a Trip Report

If you are going on a passage it is a good idea to lodge a trip report. You can do this with Maritime NZ, Coastguard or the private radio service in the area you are operating in. When lodging a TR you’ll be asked for your call sign. The format of a TR is to provide:

  • Your boat’s name and call sign
  • Where you plan to go
  • The number of POB (people on board)
  • When you plan to arrive or return

Please remember to close your TR when you have arrived at your destination.

Failing to close a TR will NOT initiate a search.  If you require assistance you must be able to call for help.  It is also a good idea to ensure a trusted person can raise an alarm from ashore if you fail to return as planned.

In the event of an emergency, a TR will help rescue authorities know where to start looking and how many people are aboard.

Obtaining Medical Advice

Medical advice can be obtained from Maritime Radio. Simply make a call on Channel 16 to the appropriate coast station for your area and then relay your message. They will then pass your details on to the appropriate medical authority and you'll get a reply when they respond. There is no charge for this service. If it is a serious emergency, you might get patched through to a doctor.

It is worth noting that any conversation you hear on the marine radio which is not intended for you is confidential and must not be repeated. This is covered under our privacy law. 

Weather Reports

Maritime NZ broadcast weather forecasts at regular intervals for all the coastal areas of New Zealand on the VHF. You can also access the Coastguard Nowcasting service which broadcasts real time marine weather information including the actual current wind conditions at various points around the coastline, tides, safety information and forecasts. You can see the weather information channels here

Distress Calls

We will cover off Mayday and Pan Pan calls in future cruising preparation workshops. If you've done your VHF license you should be well versed in how to do calls like this. But it is worth covering distress calls off with your crew if they don't have a license. 

DSC - Digital Selective Calling

If you've bought a VHF radio in the last few years, chances are it has a red distress button on the front. Lift the flap, press and hold the button for five seconds, and details of your vessel, your position, and the fact that you require urgent and immediate assistance are broadcast to everyone with a DSC-equipped radio within range. The beauty of the system is that it should summon assistance even if you're unable to speak. You can also usually select what kind of distress you are in. Two things need to happen for a DSC-VHF radio to work properly. First, it has to be connected to a GPS; second, the radio needs to be programmed with an MMSI number.

Pressing this button sets off a loud alarm on all the VHF's in range. The radio operator on that vessel needs to physically go to the set to turn off the alarm, so they will be alerted to your distress, they'll know your vessel name and your location all from the distress message.

The thing to remember though is that this message is NOT transmitted to Maritime Radio nor the Rescue Coordination Centre. Here in NZ the DSC frequency is NOT monitored by our authorities. So if there are no vessels in the vicinity to hear your distress alert, you'll still need to make your Mayday call on the VHF and potentially turn on your EPIRB too.

Individual or Group DSC Calling

One of the other really cool features of a DSC VHF is that it can be used to contact another boat directly for non-emergency reasons.

You can dial up other ships nearby if you know their MMSI numbers. For example if you see a ship heading towards you, and you want to check to make sure they've seen you, you can look up their MMSI number on the AIS, and then radio them to have a chat about how you intend to pass one another. The DSC VHF will sound an alarm on the ship's radio, and automatically switch to the channel you are calling them up on. They'll have to physically switch the alarm off and acknowledge your call. 

You can see how this works in this short video.

You can also load in the MMSI numbers of all your friends, or do a group DSC list to everyone on your Island Cruising rally for example. Yachts in a race, rally or cruising fleet can maintain a constant scanning watch for general DSC calls from other participants, utilizing the quiet/muted functionality of the DSC radio’s speaker. Yachts traveling together can coordinate a cruise, or get advice about weather, anchorages, sailing conditions, technical problems etc. This semi-private multi-party conference call is a perfect solution for groups travelling together. 

Other DSC Benefits

You can continue to have your VHF radio turned on at night, but if there is a DSC distress alert from a vessel nearby or someone calling you up on a DSC call the radio alarm will sound and wake you up. This is a great benefit, for example if you saw a boat dragging anchor at night, you could try making a DSC call to wake them up if they don't respond on channel 16. 

Fleets of vessels, yacht races and rallies can get a special Group MMSI number which you can enter once and then all the participants can simply enter one Group number instead of individually entering every single vessel. I am looking in to getting an Island Cruising rally MMSI group number and will report back to rally participants as to how this all works. 

The Phonetic Alphabet

If you need to spell out a message over the radio then you'll need to memorise the phonetic alphabet. (It comes in handy talking on the phone too). It is pretty easy to memorise, and knowing the phonetic alphabet makes you also sound like you know what you are talking about. 


So this weeks tasks are:

  1. Check and charge up the battery in your hand held VHF radio/s
  2. Download a copy of the Maritime Radio Handbook here. Or you can also order a printed copy from Maritime NZ here. Gulf Harbour Radio also have copies and they are happy to send you one if you can provide postage. Email them here:
  3. Download a copy of the Coastguard Radio Stations around the coastline here.
  4. Put copies of both of these documents in your "Passage Planning" folder. 
  5. Find the copy of your VHF license and put it in your "Boating Qualifications" folder. If you haven't got a license, then sign up for the MSROC certificate here. Encourage your crew members to do the course as well. 
  6. If you've already got a license but want a refresher, or if you are based in Australia, check out the very cost effective options for online VHF learning with Sistership Training.
  7. Check your details on the Radio Spectrum Management site. Your license details should be on there and so should your vessel call sign. Your contact details are also publicly available for everyone to see on this site - just in case you didn't know that... you can put in a request to have this information hidden by emailing
  8. If the details on your license or vessel are incorrect, including your emergency contact details, you can update them here
  9. Download the Maritime Ship License form if you are planning on going offshore. I think there is an annual fee for this license, so maybe don't apply for this one straight away until we know if we can sail offshore next year. 
  10. Once you have got everything correct, updated and collated, you should print out and file all your vessel callsign and MMSI registration details in your "Important Documents" folder.
  11. Dig out the instructions on your VHF Radio and make sure you understand how to operate the DSC calling. Check that your VHF is connected to your GPS, and that you've got your MMSI number loaded in there too.
  12. Load up all your friends MMSI numbers so you can impress them with a DSC direct call. Much easier to do this when you are at the dock and not bobbing around at sea as it is a bit fiddly.
  13. Do a radio check on your VHF with Maritime NZ. Simply call up the Coast Station for your area on Channel 16 (eg. Akaroa Maritime Radio), they'll reply and ask you to move to one of their working channels, and once you are there you can ask them to do a radio check. They'll ask for your call-sign and tell you how clearly you are transmitting. Make a note that you have done this in your ships log and do a check a week or so prior to any long voyage so you can be sure that your radio is in good working order before you depart.
  14. Commercial vessels are required to display a "distress sticker which details the vessel's call sign and the correct Mayday or Pan Pan procedure. While this isn't a requirement for recreational vessels, it is worth having this information displayed nearby. You can download the distress sticker here. Print a copy to display beside the VHF and another one for your "Safety Manual". Or you can order a proper sticker and the Radio Handbook to be posted to you here. 
  15. Add the Maritime Radio NZ contact details in to your phone, so that if for whatever reason your VHF stops working, if you are in phone coverage you can call them up to end your Trip Report or request any other assistance. Their details are as follows: +64 4 550 5280 or 0800 627 484 or

Some of the links in this workshop relate back to previous or future workshops, we have been working on collating together folders of information for your Safety Manual, Maintenance Manual and information to go in folders for your Boating Qualifications and also Passage Planning. If you are not a member, you won't be able to access those pages sorry. You can join Island Cruising to participate in more upcoming workshops including the upcoming related topics on EPIRBs & AIS. You can become a member here. Access to all our workshops can be found in our Members Area