Installing Navtex

Swearing for three days solid

Image shows Navtex unit and a taster of the million wires I had to contend with

Image shows Navtex unit and a taster of the million wires I had to contend with

The next job I undertook was to experiment with the electronics. I was keen to make the most of the GPS data by linking our electronics so that they could talk to each other. Marine electronics use a data protocol called NMEA (National Marine Electronics Association, pronounced ‘nee-mah’), which allows a standardised way of different electronics to communicate with each other. Essentially the GPS produces data that can be sent to other gizmos on the boat. For example the GPS sends the latitude and longitude to the chart plotter, whilst also recording the boat’s speed over ground, heading and so on. Our VHF can also pick up this data so, in an emergency, the VHF operator can send the position of the boat at the push of a button. Finally the Navtex (which reports localised weather data on a low frequency radio band) has a repeater that collects all the data, records it in a log and allows the operator to download the data to a laptop. Learning all this was great fun but taking the control panel off to reveal a writhing snake pit of unlabelled wires and cables was rather daunting. After a few days I’d cracked it and even managed to get the data sent to the laptop on my first attempt. One day I may attempt to paste our log data onto Google Earth, but that’s another project for a rainy day.

Navtex (topleft) with weather data displayed, along with the VHF (bottom left) and chart plotter (bottom centre), all now talking to each other. The water gauge (right) was also installed into the dash.

Navtex (topleft) with weather data displayed, along with the VHF (bottom left) and chart plotter (bottom centre), all now talking to each other. The water gauge (right) was also installed into the dash.

Perhaps our biggest job yet was the installation of the Navtex. Getting it wired up on the control panel (shown above) was the easy bit, but the aerial wasn’t picking up a good signal when stuffed in a locker in the boat. Each day we moved the aerial around the boat and experimented with different levels of reception. It was only when we put the aerial at the end of the boom, above head height, that we started receiving comprehensive weather reports. After consultation with John and Mark it was decided there was only one place to mount the aerial – on the mizzen mast.


Navtex wire threaded through mast. Rivet holes drilled and primed.

Navtex wire threaded through mast. Rivet holes drilled and primed.

For those not familiar with a boat’s layout, let me explain something. The mast is mounted to the deck and has a separate conduit inside it for wires to run down (lights, radar etc). The conduit is small (diameter of 4cm) and there are only two ways to gain access to it – either from the top of the mast or by drilling a hole half way up it. We opted to drill a hole in the mast and chance it. The next two days were then spent poking a wire down the hole and picking it up at the other end. Sounds easy. It wasn’t. In fact it was one of the most frustrating things I’ve ever done in my life! It was only through perserverence that we finally cracked it. I won’t bore you with how we did it but believe me, it was very difficult and required a very comprehensive vocabulary of swear words.


New stainless steel bracket

New stainless steel bracket

What was good fun, however, was getting the Navtex mounting bracket made. John drew up a scaled schematic of the bracket design and we measured the curvature of the mast before taking all this info to a metal-smith in the industrial estate in town. The sanayi is not like a UK industrial estate. It’s a hotchpotch of little shacks, separated by dusty lanes and oily Turks, beavering away over lathes and angle-grinders. Health and Safety would have a field day here – not one safety mask in sight in the sanayi! John took me to a shop to buy the sheet of stainless steel and a knob of solid s/s tubing. We then took this to another workshop and he introduced me to a stocky young lad who then spent the whole afternoon creating the bracket, exactly to John’s plan. As he turned the tubing on the lathe to cut the thread of the mounting base I sat and watched and was reminded of my old metal work classes at school. The difference was this guy knew what he was doing. After three hours he’d completed the job, charged me fifty yentils (£15) and we rounded off the afternoon with a çay and a three-worded conversation about boats.

Arty shot of the Navtex, new bracket and radar in background

Arty shot of the Navtex, new bracket and radar in background

Back up the mast with drill in hand I attacked the bracket with a rivet gun (yet another tool borrowed off John). After hiding the cables in the headboards we switched the Navtex on….and it worked instantly! We are now receiving decent weather reports from the stations dotted around the Aegean and now know when the Turkish airforce is doing parachute drops in the Black Sea or if there is a gale warning off the Lybian coast. Which is really useful when you’re stuck in a boatyard up on sticks going nowhere.






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