u/fuckin_atodaso — reddlx

Hey all, this is not so much an instructional guide as a motivational post for anyone else who may find themselves in a similar situation (or people who just like to fiddle).

Additional context, but feel free to skip: Our boat is 45 years and old and, while structurally in great shape, when it we bought three years ago the electronics ranged from "sporadic" to "non-functional". We've been learning to sail in the western basin of Lake Erie and, since I grew up in the area, having non-functioning equipment wasn't a big deal since I knew where to go and where not to go. However, as we ventured out more and more, it became obvious just for safety reasons alone that we needed to have this fixed before we got anymore ambitious. But with an old boat, it gets hard to justify dropping 10% of the boat's value on just a chart plotter or windicator.

So, if you have seen the Signal K guides around and are skeptical about the functionality, price, or difficulty of setting it up I am just sharing some positive experiences about, what parts we've used so far, and rough costs.

Purchase List - These are things that I bought but "do your own research" about what works for you or what you need.

Raspberry Pi 4 (w/ case and fan - $120 This is your server hub. If you want to spend the money, you can skip a lot of this and get a custom HALPI made for around $400-500.
Hawkeye Fishpod Vision - $150 This is a fish finder depth sounder, but that doesn't matter. All you really care about is the NMEA output. Only rated for 600FT. Does also have a phone app if you want to see the fish.
Sailtimer Ultra Sonic Windicator - $300 This was, by far, the most expensive part of the project.
dAISY 2+ AIS Receiver - $120 Easy to hook up AIS receiver (not transmitter), comes in a "hat" version for the Pi
Lenovo M3 Tablet + 7 inch touch screen - $120 The tablet mounts at the helm, the touch screen is for a below deck scrolling info kiosk.

At this point, you're probably roughly spending between $800-900 in and this is the backbone of mostly everything and also the most expensive part. There are a bunch of small miscellaneous purchases that you may need or want:

Glassnos Dongle - $10 Pretty vital as it will serve a lot of functions. On top of being able to give you your location, heading, and speed, you can use it to tie into weather forecasts and wave information (and probably tides, too, I don't know shit about those).
Cheap Wifi Adapter - $10 The PI has built-in wifi but you also want to broadcast for a connection to the server. This allows you to pull up whatever data you are feeding the server from any tablet, phone, etc.
Misc adapters, wires, converters, etc. - $??? This is going to be context dependent. I had to buy $25 serial adapters for the windicator and the depth finder. You will probably need some 12v-5v buck converters or in-line USB-C power supplies. You'll probably need an additional USB hub. ESP32 controllers will let you do a lot of nifty monitoring on other systems, I have one hooked up to monitor my fuel levels. You can also do things like bilge levels, engine RPM, etc. You'll probably need a bunch of misc. $5 parts you don't know you need until you try to do something that doesn't make sense without them.
Victron Smart Shunt and Smart Controller - $150 This is a side project that is not needed but this will allow you to monitor your renewable energy sources and your battery levels.
Navionics subscription - $50 Signal K comes with OpenCPN, so you don't need this. We already had the subscription and all of this ties into it seamlessly, so we are just sticking with that.
Claude Premium Subscription - $20 I work as a sysadmin and I probably still wouldn't have been able to figure out a decent chunk of this on my own. There are a lot of different moving parts going on here and if you don't already have a familiarity with marine electronics, small electronics, and Linux then you may hit several walls. I still hit several walls.

So, all in all, I have probably dropped $1500 on this project because, like a lot of projects, it started to balloon in scope and I was bored all winter. Everything works exceptionally well. The effort people put into maintaining the open source community should be applauded, and it was cool to see all the other boutique and affordable options outside of Garmin, Raymarine, etc. There are many good guides out there to get started. Absorbing it all at once can be difficult, so I found it better to just focus on one piece of the puzzle at a time. Once you get the hang of the base functionality, more ideas will pop into your head.

Obviously, there are limitations here that may or may not be feasible depending on what your needs are. I think with a nicer boat that I know I would have for a long time, I probably would have dropped the money on dedicated instruments along with the Signal K setup.

Happy to answer any questions for anyone curious. Or, if you've done it also, would love to hear your experiences and what you've done. Cheers, happy sailing.