One of those days

Ever have one of those days where everything you try to do doesn’t work? Yeah.

First I started to rebed 2 more of my chainplates. Got most of the way through, and then ran out of resin. Ugh. So then I decided to figure out the connection from my chartplotter to my laptop.

I was using a program called OpenCPN, which is open source and free. The idea was that I could plot courses in the comfort of my cabin one evening before a trip, and then upload them to my chartplotter, while grabbing GPS data, wind speed etc from the chartplotter to the laptop, meaning I could view wind speed etc at anchor without having to go on deck.

Simple right? Except OpenCPN doesn’t support NMEA2000 (which everything else uses). Which meant I had to use NMEA0183 – which as it turns out, my chartplotter bridges all the NMEA2000 info and spits it out as NMEA0183 on a port (excluding AIS).

SO, in theory, all I had to do was take that wire, hook it up to a DB-9 serial connector, and whack it on my PC.

Hookin’ up some tiny wires, do do do


Configuring the NMEA sentences on the NSS8, la la la


….. aaaaaaaaaaaand the bloody thing refuses to work, fffffffffffffffffffffffffffffffff

Ok, I find a slip of paper saying the wiring diagram for the NSS8 is wrong, and the tx/rx wires are reversed, ughhhhh, so I reverse them.

More faffing around with tiny wires



Still doesn’t work. Cue frustrated screeching.

Using a port monitoring program I can see that the laptop can see incoming messages from the NSS, it’s just not being picked up by OpenCPN.



Here is the connection window in OpenCPN


So, I’m at a bit of a loss.

To sum up, everything I tried to do today was a dismal failure – but at least nothing caught fire.



  1. NMEA 2000 is a compact binary message format as opposed to the ASCII serial communications protocol used by NMEA 0183.

    Is OpenCPN expecting ASCII or what ?

    So the question is does the plotter reformat the message or transmit nema2000 packet at the slower rate ? Skip

    • Yeah, my chartplotter takes the N2k input, reformats it and outputs it as a serial NMEA0183 output. I can see it transmitting but OpenCPN doesn’t seem to want to handle it :\

    • Throwing the whole mess into the ocean and having a beer occurred to me more than once…

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