CAN bus tools for boats
Read what's on your NMEA 2000 backbone, your engine's J1939 bus or an electric motor controller's CANopen link — from a single identifier to a whole log file.
Decode a 29-bit NMEA 2000 / J1939 CAN identifier into priority, PGN, source and destination, or an 11-bit CANopen COB-ID into function and node — and build an ID from its parts.
OpenPaste a CAN identifier and data bytes and get the decoded fields: 639 NMEA 2000 PGNs from the canboat database, J1939 engine messages and DM1 fault codes, CANopen NMT, heartbeat, SDO and EMCY..
OpenUpload or paste a candump, PCAN-View, Yacht Devices YDWG-02, Actisense or Vector log: fast-packet and J1939 transport reassembly, per-PGN summary, filtering and decoded CSV export.
OpenExtract a signal from CAN data bytes by start bit, length, byte order, sign, scale and offset — with a bit map — or encode a physical value back into the bytes.
OpenWhich bus is which
| Protocol | Where you find it on a boat | What the tools decode |
|---|---|---|
| NMEA 2000 | Instruments, chartplotters, batteries and chargers, engine gateways | 29-bit IDs. Victron VE.Can is NMEA 2000-compatible, so its traffic decodes here too. |
| J1939 | Diesel engines and generator sets | 29-bit IDs, same ID layout as NMEA 2000 (which builds on it); engine data and DM1 fault codes. |
| CANopen | Electric-drive motor controllers such as Sevcon Gen4, Curtis 1236E/1238E and emDrive | 11-bit IDs: NMT, heartbeat, SDO parameter access, PDO process data, EMCY errors. |
Everything is decoded in your browser — logs and frames are never uploaded. Message layouts come from these documents; where a source doesn't define something, the tools show the raw bytes rather than guess.
- canboat — NMEA 2000 PGN database v9.0.0 (Apache License 2.0) — NMEA 2000 PGN layouts, lookups and fast-packet / ISO transport framing
- DynaGen (Cattron) TOUGH Series J1939 Reference Manual 9M02-9252-A201 — J1939 engine PGNs/SPNs, DTC layout
- Mecc Alte MxK CAN-Bus Technical Guide — J1939 DM1 lamp bits and values
- Schneider Electric Machine Expert — IoDrvJ1939 FMI (ENUM) — J1939 FMI names
- Faulhaber Communications Manual 7000.05050 (CANopen protocol description) — CANopen COB-IDs, NMT, heartbeat, SDO, abort codes, EMCY
The NMEA 2000 definitions are derived from canboat, © 2009–2026 Kees Verruijt, under the Apache License 2.0. NMEA 2000® is a registered trademark of the National Marine Electronics Association; canboat's definitions are reverse-engineered, not the official NMEA database. Check critical values against your equipment's documentation.