Upgrade Your Boat - Part 8 - Communications

By Simon Boyde

Communications Equipment

In the last article I outlined the requirements of the GMDSS and what we were going to do about it. For us this means new radios - VHF fixed, handheld, and MF/HF. A Sat C terminal, Navtex receiver, EPIRB and SART. This is what we chose:

GME GX600D Radio - including DSC function


We selected the GME GX600D fixed DSC radio. GME are an Australian manufacturer and make a very nice radio which has in its one box in fact two radios - there is in addition to the voice transceiver, a dedicated DSC transceiver. A nice feature of this radio is its handheld controller.

Cave CanemMF/HF DSC Radio (what we used to call an SSB)

There are not many players in the marine MF/HF radio business. The big business is commercial shipping, and they are not overly concerned if a radio weighs 35kg or even 100kg, they care about reliability.

Cave Canem though is a different matter. We do care about weight and size. With the advent of DSC there is really only one player in the market for us, and that is ICOM.

We have gone for the ICOM M801E model. Good radio (as all the ICOM radios are) which has a fully encased radio box (splash proof) and a method of boosting voltage from the supply to make sure that it gets enough to transmit: it incorporates a DC power booster so that the radio, which needs 13.2V to operate, can actually operate off 11.6V.

This is important - the only way to normally get 13.2V+ on board a yacht is to run the engine so that the alternator kicks out the required voltage and current. But what is of course very common in an emergency (when you might need to call for help) is that the engine won't start!

There is an alternative designed for the US fishing boat market. The M802 is DSC compliant (well most versions - check that you are buying the DSC compliant one). This market is highly competitive so two important features have been left out to save money. This radio is NOT splash proof and does NOT have a DC booster in it. Not a great issue if you have an engine running 24 hours a day like a fishing boat or other offshore motor boat, but a big issue for a sailing yacht.

Plus side for the M801E is it is likely to work after your boat has been rolled. Downside is cost (around HKD8,000 more expensive than the M802. The M801E, with antenna tuner, is around HKD24,000).


NASA Marine Clipper Navtex receiverNAVTEX is awesome! All over the world (apart from Australian and NZ waters for some bizarre reason) NAVTEX transmitters chuck out weather forecasts every four hours, repeat long standing navigational warnings on a similar schedule, and if anything urgent, weather or navigational wise comes through, sends it out straight away. Free. You receive it on your boat and can read it on a little text display.

Fully compliant GMDSS NAVTEX receivers print out everything they receive on paper. A real pain on a sailing boat offshore and unnecessary for us. We do not have to put copies of weather reports in our radio log. An entirely acceptable NAVTEX receiver from Nasa Marine from the UK is available and this is what we have purchased. Their Clipper NAVTEX receiver I have been using for a number of years and it is fine. Cost is around HKD3000. Cheap - weather reports every four hours up to around 200 miles out (depending on transmitter) with navigational warnings and met warnings transmitted as required.


Sat C is the big brother of NAVTEX. Whereas NAVTEX does coastal weather, Sat C does the high seas. This satellite system is effectively mandatory on every commercial ship which goes offshore, which means at the moment there are around 80,000 Sat C terminals cruising round the world.

Different countries' Met offices and Coastguards (HK Observatory and the Marine Department in HK) send information out on Sat C which gets broadcast to everyone under the footprint of the satellite you are under (four satellites, geostationary above the equator, giving worldwide coverage). In areas without NAVTEX coverage, Sat C may be the only way to get good weather warnings. This includes the Philippines, Australia and New Zealand by the way.

Cost, what about cost? Well, all of this inbound data is free of charge. You only pay if you send personal (ie routine) messages or receive them. Sat C supports an email interface which gives access to the internet for email.

Sat C is the way to get weather reports and warnings at sea. It works worldwide bar the poles and in certain parts of the world is the only way to receive such warnings because of holes in NAVTEX transmitter overlaps.

The cost for our Thrane & Thrane TT3026D unit was around HKD25,000. We use as the terminal the same Digital Yacht PC we are using to run Expedition.


When buying an EPIRB there are many manufacturers out there who make great ones - GME, ACR, McMurdo are all good, and there are many more manufacturers to be found.

GME MT403G EPIRB from Storm Force Marine in Hong KongMake sure however that you can get the EPIRB programmed locally with your MMSI number (the same number is issued to you to program into your DSC radios) as this is your identity which the MRCC will be using to identify you and try and locate you in an emergency.

Some countries permit you to serialize EPIRBs (ie not have them programmed especially for you) but Hong Kong does not - it must be programmed with your MMSI number and most website suppliers cannot do it for you.

EPIRBs come with or without a GPS - get it with a GPS as the time taken to get your position down to ground is around 10 minutes from a GPS EPIRB but can be 90+ minutes if not GPS-equipped. EPIRBs also come in an auto release housing or not. In general the auto release housing is a good idea, just a real pain to find a place to put it on a sailing boat. I have gone for the GPS equipped, non auto release GME MT403G.

Search and Rescue Transponders (SARTs), when activated, help guide a rescuing ship to your location. Again, lots of manufacturers around the world. No programming is required on SARTs. However, we want light weight and compact sizing and about the smallest and most compact is from Sevenstar Electronics. Neat little unit.

Handheld VHF radio

Marine Hand Held VHF RadioWe all have these on board, and we all get round race regulations that state that there must be spare batteries for it by buying an additional rechargeable battery. Now here is a challenge - charge up that spare battery, leave it on the boat for two weeks then connect it to your radio. You will find it is nearly flat.

Not something to rely on when you hit the liferaft! The preferred method is a GMDSS handheld which has as a replacement battery a sealed Lithium battery with many long years of storage life on a boat.

An alternative (and in my case an addition) is a conventional leisure marine handheld VHF with a replacement battery pack into which you can insert long life alkaline batteries (Duracell or similar).

The GMDSS handheld VHF is designed for a lot of abuse and I would recommend that you get one of these. For chatting, a leisure marine one is fine, but remember the replacement battery pack. I have gone for the ICOM GMDSS handheld and the ICOM M35 handheld with replacement battery pack (code for that is BP251 by the way!). Joy of joys, they share the same charger.

Additional Communications Equipment


ISAF LogoISAF in their wisdom have made it mandatory to have AIS installed on boats racing in Cat 1 or Cat 2 races. On this front I am in complete agreement with ISAF because what this does is magic.

Every commercial ship in the world has AIS (Automatic Identification System) on board - it is law. AIS is a small box containing a transceiver which, at frequent intervals, transmits a short data burst in the VHF band which contains your vessel information - name, callsign and MMSI no, your position, and current course and speed. For mandatory fit vessels there is in addition information on the current voyage (from, to and cargo) as well as big ship things like rate of turn. Luckily we don't have to put that in each time, we just switch it on before we start moving.

That same transceiver receives data from all of those other vessels, and most recent chart plotters (including Expedition) can then take that information and put it on a chart plotter display. Sort of a poor man's radar, but better than radar in many respects, because you get identification of the ships round you.

It is primarily an anti collision device - this has happened to us, coming back from Macau, I had once again forgotten to refuel, 8PM off Cheung Chau in little or no wind and the jetfoils screaming past. If I could have called them up (using the DSC radio to send an alert to them, and knowing their MMSI no from their AIS transmitter) I could have told them my situation so they could avoid me. It was very uncomfortable! On the way back from the last China Sea Race we were caught in thick fog on the run into Hong Kong and the AIS unit was in the office. Very scary and very stupid indeed!

Comar are the oldest and still the best of the AIS Class B makers. They have been supplying Class B units for some years now and they are very robust units. Recently they have developed a neat antenna-sharing device which means that your fixed VHF radio antenna, on top of the mast, is also your AIS transponder antenna. Nice and high, nice big range. We have put on their CSB-200 unit with their AST-200 antenna splitter.

Nice to have but not happening yet

Radar. Yes - but with the load of everything else it is coming later. We will make do with sharp eyes and ears and our AIS in the meantime. At the moment, new ultra low power units are coming on the market and I think radar prices will drop. We will revisit this later in the year.

Satellite Phone. Yes - definitely going on board, but cannot afford that and Sat C so Sat C came first (of course). I will add it, it is useful to be able to make a phone call from sea, but I do recognise that in a rough seas distress situation a satellite phone is unlikely to work. Current offerings from Inmarsat are very good, though alas not portable (at least not at sea). Iridium do LEO sat phones which can work quite well from their built in antenna, and if installed in their cradle with a proper external antenna are a very good option to the Inmarsat phones. Do remember the external antenna though, otherwise you will find that in rougher weather the phone will drop out very easily.

Where do you put all the aerials?

Good question. And made worse by the fact that an MF/HF DSC radio requires two antennas - one for transmit and voice receive, the other for DSC receive (and as almost no yachts in Hong Kong have DSC receive antennas installed, you can see why bar talk has it that DSC is not used>. It isn't true - it is just that without an antenna that they can't receive any alerts!).

We could have put all the antennas on the pushpit rail - and in fact that is where I had my Navtex antenna before the upgrade. It is also why I have bought three Navtex antennas in the last two years - people kept on grabbing them and breaking them.

I was looking round the new Oyster that just arrived - it has a raked railing installed at the top of the mast to accommodate the antenna space. Though it looks perfectly acceptable on the Oyster, it is not a route I would chose to go (too much windage), so I have come down on the side of putting in an instrument arch.

On this arch is mounted the Navtex, MF/HF DSC receive antenna, and the Sat C antenna. Later we will add the sat phone and radar antennae to the same arch.

Instrument Arch

Not the best addition to the boat looks-wise, but this is the only practical way for permanent installation. (It has also proven useful for people standing in the stern). An alternative for a more racing-inclined owner would be to pushpit mount the new antennas and then, on the return from the offshore trip, demount them (except for the Navtex of course). Too much of a pain for me so permanent arch it is.

So, all pretty much installed now, and time for a pause in our update program for Cave Canem while we prep her for the offshore trip to the Philippines. We are due to set off on April 1st and I hope to report back to you on how well this all worked - and also of course as we restart our upgrading program.

Simon Boyde is a Director of Storm Force Marine and regularly races Cave Canem