Formosa 51 · refitting now
Erik and Tara, two dogs, and a 51 foot fiberglass ketch called Exodus. We're on the Chesapeake at the moment — working, saving, and refitting her. The plan is to quit the jobs, let go of the dock line next winter, and keep going as long as we can go.
The honest version
Not cruising yet. Refitting.
That means jobs, and weekends in the bilge, and money going into the boat instead of anywhere fun. The Chesapeake isn't home, it's where the work is getting done. Every system we touch is one less thing to fail three thousand miles from a chandlery.
Target is next winter. Sell what doesn't fit aboard, hand in our notice, and go. A circumnavigation if she'll carry us that far — and as far as we can get if she won't.
Both, on purpose
We run proper marine gear. We also run open source alongside it. Not instead of — alongside.
The brand-name kit does the job, but anyone who has lived with it knows the failings: it can be unreliable, it's finicky, and it isn't as robust as the price tag suggests. When something goes wrong a long way from help, "call the dealer" is not a plan.
So there's a Raspberry Pi aboard reading the same instruments, keeping its own records, and in some cases doing things the expensive box won't. If the chartplotter dies at three in the morning, something else is still watching.
That's also where the projects come from. We'll put the good ones here — what worked, what didn't, and enough detail that you could actually do it yourself.
Radar and sonar, decoded on the boat
Marine radar and fishfinder pictures are proprietary. Not encrypted, just undocumented, and nobody publishes the formats. In one night we captured both off our own instruments and worked out what the bytes meant — then put them on a screen no manufacturer sold us.
The fishfinder turned out to be announcing its own frequency setting in plain readable English, seventy-one times a second, in a field nobody was ever supposed to look at.
| What it needs | On the wire | Open? | |
|---|---|---|---|
| Depth number | one measurement | 8 bytes/sec | Yes · NMEA 2000 |
| Sonar picture | the whole echo return | 150,000 bytes/sec | No · ethernet, closed |
The reason you can contribute to crowd-sourced charts but can't get a fishfinder on an open screen isn't a conspiracy. One is eight bytes. The other is a hundred and fifty thousand.
Exodus