A Raspberry Pi 5 with a PiCAN-M board makes a capable chartplotter and instrument display. It connects to your boat's NMEA 2000 network, runs on the boat's 12 V and costs a few hundred dollars in off-the-shelf parts. This guide covers what to buy, how to put it together, and how to get charts and your boat's data on screen with MarineOS Helm, chartplotter software made for this hardware.
What you need
| Part | What to look for |
|---|---|
| Raspberry Pi 5 | 4 GB of memory or more. The official 27 W power supply is handy for setting up on the bench. |
| PiCAN-M | A HAT from Copperhill Technologies with an NMEA 2000 Micro-C connector and NMEA 0183 (RS-422) terminals. Its optional 12 V power supply runs the Pi from the boat. |
| A touch screen | The Raspberry Pi Touch Display 2, or any HDMI screen with USB touch. At an open helm, choose a bright, sunlight-readable one. |
| A microSD card | 32 GB or more, A2 class: room for the software, your charts and the boat's history. |
| An NMEA 2000 drop cable | Micro-C, from the PiCAN-M to a free T on your boat's backbone. |
| Somewhere dry | The Pi and the HAT aren't waterproof: mount them in the console or at the nav station, or in a sealed enclosure. |
Everything plugs together, with no soldering. Because the parts are standard, any of them can be replaced or upgraded on its own: a brighter screen, a bigger card, a newer Pi.
1. Write the SD card
- Download the MarineOS Helm SD card image from the MarineOS Helm page.
- In Raspberry Pi Imager, choose Raspberry Pi 5, then Use custom and the image, then your microSD card.
- When Imager offers OS customisation, set a username and password, your Wi-Fi and your time zone. The image has no default password.
The image is Raspberry Pi OS with MarineOS, set up to start full-screen when the Pi powers on, with the PiCAN-M ready.
2. Connect it
Fit the PiCAN-M to the Pi, and connect the screen. Run the drop cable from the PiCAN-M's Micro-C connector to a free T on your NMEA 2000 backbone. The backbone needs its own 12 V power and a terminator at each end; the NMEA 2000 guide covers this in detail.
Put the card in and power up. The first start takes a minute or two longer while the card is prepared; then the chart fills the screen.
Older instruments that talk NMEA 0183 can be wired to the PiCAN-M's RS-422 terminals instead (or as well). One port both reads instruments and sends navigation data to an autopilot.
3. Set it up for your boat
- Settings › Data Sources: check that NMEA 2000 (can0) sees your instruments.
- Settings › Boat: set your draft and height. Auto Guidance plans routes around them.
- Settings › Charts & Tides: download charts for where you boat. NOAA's charts are free; the charts guide explains what's available.
- Settings › Network: join a Wi-Fi network, for chart updates, weather and software updates.
4. Pair it with your account
The first time it starts, the helm offers to join your MarineOS account and shows a QR code. Scan it with your phone and confirm. Once paired, your boat shows on your phone and in your browser, the routes you plan at home come aboard, and software updates arrive by themselves. Push one from your boat's page, or let the helm install each one when the boat has been stopped a while: never underway.
What you get on the water
- Official NOAA and U.S. Army Corps of Engineers charts on board, with no signal needed.
- Routes, waypoints, Go To, and Auto Guidance, which plans a route around your draft and height.
- Position, speed and course, heading, depth, speed through water, wind, water temperature, battery, fuel level and engine RPM from NMEA 2000.
- Alarms, including shallow water, off course and anchor watch.
- Your route sent to the autopilot over NMEA 2000 or NMEA 0183 (autopilot control is in beta).
- The weather forecast on the chart, and a boating comfort forecast.
What it costs
The hardware is a few hundred dollars, from any supplier. The software is free for 30 days; after that, a MarineOS Helm license is a one-time $199 per boat, for up to 3 helm displays. It's a software license only: hardware isn't included. See pricing for what MarineOS Plus adds.
Raspberry Pi chartplotter or a commercial MFD?
A commercial multifunction display is sealed, sunlight-bright and supported by its maker, and costs much more. A Raspberry Pi helm costs far less and uses parts you can replace yourself, but it needs a dry place to live and a screen chosen for your helm. Many boats use both: a Raspberry Pi at the nav station or flybridge alongside an existing Garmin, Raymarine or Furuno. MarineOS reads and writes GPX, so routes move between them.
Questions
Do I need the internet on the water?
No. Charts are on board, and the helm works with no signal. It uses Wi-Fi or your phone's hotspot for updates, weather and your account.
Can I use more than one screen?
Yes. One license covers up to 3 helm displays on the same boat, for example the helm, the flybridge and the nav station.
Does it work with OpenCPN?
MarineOS is its own chartplotter rather than an OpenCPN plugin, but routes and waypoints export as GPX, which OpenCPN, Garmin, Raymarine and Navionics all read.