Going Wifi

Recently I’ve been partaking in some chitchat on the YBW.com forum about the optimal design of a navigation system onboard. Now, as I installed a navigation PC on Karisma back in the spring, I am always looking for ways to improve and upgrade the system, and the chat turned to how to integrate wireless devices- smartphones, tablets- into an electronic setup.

For some time commercial chartplotters have been available which are wifi-enabled and, if you download propreitary apps- like Raymarine’s Raycontrol, which is probably the most established- you can repeat the instrument data displayed on your chartplotter on an iPad, iPhone etc. I have a chartplotter sitting in our spare bedroom ready to install on Karisma- a Simrad NSS7, a very recently discontinued N2K plotter which matches the other parts of the Simrad system onboard and, unlike the new Evo2 generation plotters, retains an  all-important NMEA0183 port. However, this plotter isn’t wifi, and although Simrad do make a wifi bridge for their N2K network (the ‘GoFree‘), I don’t really need it to be, because it is intended to be a complimentary, cockpit mounted navigation system, while the real navigation work is done on the dedicated PC. In truth, I don’t need the system to be wifi-enabled at all, because the only place on the boat where you can’t see either the cockpit instruments or the Nav PC screen is when tucked up in the fore or aft cabins. But still, the Nav PC has a fully aggregated NMEA data stream at one end and a wifi aerial at the other, and I’m always keen to try new tech things. Could I make it transmit NMEA to a phone or tablet over wifi?

Well, actually, the answer is yes, and it turned out to be much easier than I’d supposed. An iPhone can be used to create a local wifi hotspot, and the PC can be connected to this hotspot, establishing the initial ethernet (wireless) network across which the NMEA can be streamed to that iPhone, or any other devices connected to its hotspot.

Now Jenny and I both have iPhone 5c’s, and I’ve tried this hotspot thing before, in order to get the PC connected to the internet when away from marina wifi, mostly for the purposes of downloading GRIB files- and it has never worked properly. For reasons previously unknown, the PC simply churned and said ‘attempting to connect…’ before failing to connect. Nothing I’ve tried could solve the problem, so I’d rather given up on it.

Today however I discovered the simply ridiculously stupid answer courtesy of some dilligent person on the microsoft help forum. It seems if the iPhone’s device name (mine was called ‘Huw’s iphone’) contains spaces, Windows 8.1 cannot connect to it. If you remove the spaces, (my phone is now called ‘Huwsiphone’) the problem disappears. This is what’s frustrating about technology; there is no way that bug could have been discovered and resolved by deduction, because it has no connection to the problem (that’s one reason why it’s a bug of course); only blind experimentation can find a solution. Hey ho. But I now had a working wifi connection between the PC and my iPhone, so the next step was to set up the NMEA data stream.

This is where the always excellent NavMonPC came in. To stream data over wifi you need to establish an ethernet connection between an NMEA server (on the PC) and a client (an app on the iPhone). To do this you need to set up a TCP/IP server, and NavMonPC, which already aggregates all Karisma’s NMEA data, can be configured to provide one. It’s just a couple of clicks in the left-hand panel as shown below- check the autostart button, then click ‘start’, and NavMonPC starts streaming NMEA out over wifi.

Network serverThe other end of the equation was, how to see the data at the phone end? There are several apps for tablets and smartphones out there that can display NMEA data, but most are charting apps, which are relatively high cost due to the included cartography, and all I wanted to see was the boat’s instruments. Tucabo’s boat instruments app only cost £4.99 and it integrates nicely with the rest of our nav software, as Tucabo is the company that makes Imray’s tablet/smartphone products and we use both paper and digital Imray charts.

All you have to tell the app is the name and IP address of the computer which is sending the NMEA data, together with the port number on which to find the data stream. This can be any number at all, as long as they are both the same:

IMG_0855And miraculously, the app’s dials and displays come alive with your instrument data. The boat was of course tied up while I did this, so there’s no speed (or, a speed of zero) but the wind data looked great on the iPhone:

IMG_0850And the AIS display was particularly good:

IMG_0852Overall, a really impressive result. As tablet and mobile devices become ever more common, the technology is bound to become more useful over time, and Karisma is now equipped to navigate in this way if we so wish- all for just the cost of the app itself.

As it’s winter, and there’s little sailing to be done, I did say the blog might become a little more techy. Another application I’ve been playing around with is PolAuto, a little-heard-of piece of software (perhaps on account of being French-developed, despite there being an English version) which draws boat speed polars from the NMEA data stream. To my knowledge it is the only freeware thing out there that can do this- polars are normally the preserve of the high-end navigation packages like SeaPro, Adrena and Expedition. First results are encouraging so look out for a blog on this one soon.


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