NMEA not connecting

Modified on Fri, 8 May at 5:18 PM

If KnotWise is not receiving data from your NMEA instruments, work through the steps below in order.

1. Check your plan and platform

NMEA live data requires two things simultaneously:

Share plan — NMEA is not available on Free or Sync
Desktop app — NMEA is not available in the browser or PWA. Download the desktop app from knotwise.app/download

2. Check your NMEA device

Confirm the device is powered on
Confirm it is connected to the same WiFi network as your computer
From a terminal or network tool, verify the device is reachable at the IP address and port shown in Settings → NMEA Integration

3. Verify host and port settings

In Settings → NMEA Integration, confirm the host IP address and port number match your NMEA device exactly. Refer to your device manual for the correct values. Common defaults are port 10110 (YDWG-02) and port 2000 (Actisense).

4. Restart KnotWise

Fully quit the desktop app and reopen it. After an automatic app update, the NMEA bridge occasionally requires a full restart to reconnect. Use Quit from the app menu — do not simply close the window.

5. Check your NMEA protocol

KnotWise supports NMEA 0183 via serial or TCP only. NMEA 2000 is not directly supported. If your installation is NMEA 2000, you need a bridge adapter that outputs NMEA 0183 — such as the Yacht Devices YDWG-02 or the Actisense NGW-1.

6. Test the connection with an external tool

Before assuming a KnotWise issue, verify that your NMEA device is actually reachable and streaming data. The quickest approach:

Platform	Tool	How to use
macOS	Terminal (built-in)	`nc [host] [port]` — NMEA sentences appear immediately if the device is reachable. Press Ctrl+C to exit.
Windows	PuTTY (free)	Open PuTTY → Connection type: Raw → enter host and port → Open. NMEA sentences scroll in the window.
macOS / Windows	OpenCPN (free)	Add a TCP connection in Options → Connections using the same host and port. If OpenCPN receives data, the NMEA stream is confirmed.

If none of these tools can reach the device, the issue is with your NMEA hardware or network — not with KnotWise.

7. Check for concurrent connection limits

Many NMEA WiFi adapters allow only a limited number of simultaneous TCP connections — some devices allow only one. If another application (OpenCPN, a chart plotter, another device) is already connected when KnotWise tries to connect, the connection will be refused.

To rule this out:

Close all other applications that may be connected to your NMEA device
Disconnect any other devices (tablets, phones) that use the same stream
Try connecting KnotWise again

Refer to your NMEA device manual for the maximum number of simultaneous connections. The Yacht Devices YDWG-02 supports up to 5 — most budget adapters support only 1.

Still not connecting?

In the NMEA Integration settings, tap or click «Show log» and then «Contact support» — this opens an email to support@knotwise.app with the technical log pre-attached. We will investigate promptly.