Every tool, chart source and database we actually use aboard, sorted honestly: what's free, what's free-ish, and what we pay real money for.
The software running this boat — all of it free, all of it yours to change
The open marine data standard. Reads NMEA 0183, NMEA 2000 and more, and turns the lot into one set of names anything can ask for. The keystone of the whole setup.
Raspberry Pi distribution that installs Signal K, OpenCPN and the rest in an afternoon instead of a month.
Navigation and weather routing. Genuinely free, and seriously capable — it will even draw a radar from a mayara server.
Wire logic together by dragging boxes. How a lot of the boat's automation gets built without writing much code.
Kees Verruijt's NMEA 2000 database, reverse engineered from scratch and given away. Everything else stands on it.
Puts marine radar onto open software. The reason our Quantum draws on a Raspberry Pi.
Victron's own firmware is open source. Venus OS Large adds Node-RED and Signal K straight onto the GX device.
Turns a cheap SDR dongle into an AIS receiver. Free targets on your own screen, no subscription.
Chart plotter in a browser, built on Signal K. Routes, waypoints, anchor alarm — and a radar panel now too.
Open-source sonar hardware. Schematics and board files published, raw echo data out the other end.
The group chat
Everything technical here is one boat's experience, and some of it will be wrong.
If you spot a discrepancy, know better than us on something, want to add to a project, or just want to talk about any of it — there's a group chat. No gatekeeping, no subscriber requirement. Turn up and join in.
We'd rather be corrected than confidently wrong, and the whole point of writing this down is so other people can build on it.
The Discord opens shortly. In the meantime, the comments on the channel reach us just as well.
What runs the offline brain aboard
Runs a language model on your own hardware. Free, open, and no connection needed once the model is downloaded.
The open-weights model we run locally. Free to download and free to use offline.
OpenAI''s speech recognition, open sourced. Runs entirely on your own machine — no key, no per-minute charge, no audio leaving the boat. faster-whisper is the quick one; whisper.cpp is the one that''ll run on a Pi.
Open-source text to speech. Fast enough for real time on a Raspberry Pi, and the voices are genuinely good. This is how the boat talks back.
How the boat reaches us and we reach the boat. Bots are free to create and free to run — and you make one by talking to another bot called BotFather.
The online half — the teacher. Paid, and the one piece here that isn't free, but it's what writes the tools that then run on the boat without it.
Public, government and crowd-sourced — no account, no fee
Every US electronic navigational chart, free. The same data the commercial apps repackage and sell you.
Predictions and live station data for every US tide station, with an open API.
Inland electronic navigational charts for the rivers and waterways NOAA doesn't cover.
Pilot charts, sailing directions, light lists. The pilot charts are how you plan an ocean crossing by season.
Live wind, wave height and sea temperature from buoys offshore. Real observations, not a model.
Marine forecasts, GRIB data and warnings, free and with an open API.
Bathymetry, lidar, shoreline and imagery datasets. Enormous, and all free.
Crowd-sourced bathymetry. Soundings from boats like this one turned into charts anyone can use — and you can contribute your own.
Free GRIB weather files for the common models, and it plugs straight into OpenCPN.
Raw GFS model output, straight from the source. This is the data most GRIB services repackage.
GRIBs delivered by email — which is the only thing that works on a satellite or SSB link offshore. Request by email to query@saildocs.com.
Free
Forecasts everyone knows. Less well known: you can register your boat as a weather station and feed real observations back in.
Satellite imagery, and the best way to see what a reef or an anchorage actually looks like before you commit.
Usable without paying, better if you do
Share your AIS feed and get the global network back in exchange. Free, but only if you contribute data.
The AIS map everyone knows. Free to look at, paid for history, coverage and detail.
Personal weather stations worldwide, including plenty on docks. Free to read, free to contribute your own.
Cruiser-built anchorage and services database. Free, and better the more people add to it.
Because sometimes you should
We're not pretending everything can be free. These earn their money, and saying so is more useful than pretending otherwise.
Weather routing and forecast models. When you need a real routing answer for a passage, this is what we use — not an LLM, not a guess.
Charts with sonar-derived detail and a good phone app. Worth it for the places NOAA surveys thinly.
The reason any of this is online offshore. Expensive, and genuinely changed what's possible on a boat.
Our radar, plotter and instruments. Good gear, with the usual proprietary walls — which is half of why this site exists.
Exodus