Fun With Boat Electronics
The lightning strike was close by. We could see that it had hit one of the boats just down the dock from ours. Phew. It wasn't a direct hit we said from the dry comfort of a nearby restaurant.
But things happened.
In the days after the strike, several electronic systems on the boat were not working properly. Autopilot was out and the sound system was sketchy, Wind instruments worked intermittently. VHF radio worked, but could not read the GPS signal. The helm digital displays (IS40) worked intermittently.
Although pretty competent with computers and networks generally, I had never done any work with a boat network. Work was busy, so we had the boat dealer's mechanic take a look at it. His conclusion was that there was a problem with the chart plotter. We weren't really interested in buying a new chart plotter, but if that was the problem...
On the word of the mechanic, we were able to get a partial refund under warranty from Simrad. We even upgraded to the next size chart plotter. All was well. Except it wasn't. Nothing worked still.
We had two other techs look at it, they both did not have a solution (although they might have replaced a wind instrument somewhere along the line). Still no dice.
Finally, we had a Simrad factory authorized tech come and look at it. His conclusion was grim. He couldn't isolate any problems in the system. His advice was to scrap the entire system replace all the network wiring and all devices. He estimated the damage at about $25k. Insurance would not cover it.
Mumbling under my breath that "If you want something done right..." I started reading up on NMEA2k.
It is just supposed to work, easy plug and play, well that wasn't happening.
There were resistance specifications, terminating resistors, and all kinds of other details that could be the problem. I bought a multimeter and a Simrad terminating resistor and went to the boat armed with an iPad so I could look up specs and pin orders on the plugs, and a telephone to call Simrad tech support.
The following events took place over a few months as I called, ordered parts and equipment, went out to the boat for a few hours to try things, and processed results in my head.
Checked all the physical characteristics - everything checked out. The system votagess and resistances were within specs.
Upgraded software. Had to go on a computer downloaded upgraded firmware from simrad, get a card reader so I could transfer it to the NSS 9 chart plotter. This was mostly pretty straightforward once I had the equipment and knew what to do, but I could not get the VHF radio (RS40) to upgrade. Eventually, they suggested I send it in and they would test it and either send it back or replace it. They replaced it and I got it installed eventually. I had to realize that the panel was removable, and and and. I was a total beginner at this.
I tried to figure out the network topology (wiring diagram). Forward was pretty simple, but working back, there was a mini-bus or something that I couldn't find. I still haven't figured out where one of my network connections comes from. It turns out it didn't really matter because I just went to the next step.
Isolate potential issues. Methodically disconnect, turn the system on, see the response, reconnect, see system response, turn off the system, disconnect something else, turn on the system, check response, etc.
I started forward, disconnecting the Depth and Speed instrument and wind meter. Nothing changed. I left them unplugged and disconnected the Fusion sound module and the radio, nothing changed.
Apparently, the problem was in the back then. I replugged in the forward instruments and worked methodically backward, instrument by instrument, until boom. Suddenly the IS40 displays were working again. It turns out there was a problem with the rudder control and also the autopilot.
We replaced those devices (having already replaced the VHF), and suddenly everything was fine. The entire system worked, the radio was getting a GPS signal, the wind instruments were reading on the displays. The network was working as it was supposed to. It has been working for three years since without a hiccup.
Insights and Lessons Learned
- There is a part of the country that is anti-science and anti-expert. I am not in that group. Generally, I believe experts. The challenge can be in actually finding one and also finding one whose interests are aligned with yours. The first few people who looked at the system were really just generalists. When we got the actual trained expert in, he was either too lazy or busy to dig, or else was motivated to sell me a new system. I am fortunate enough to know something about electricity, computers, and networks, so I was able to use my google fu skills and learn that they were not giving optimal advice for me.
- NMEA 2K marine network standard is pretty good when it works. One issue is that the standard was created, they gave a lot of leeway to equipment manufacturers to customize hardware and software to lock consumers into their equipment (the razor blade business model).
- I spent about two days troubleshooting, fixing, learning, and researching the problem. The total cost was about $1000. I also learned a lot about the boat's electronic systems. I consider this a bargain compared to dropping $25k to replace the entire system.
