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GPS position is not appearing or has appeared and no longer does or cannot see COG\SOG
Diagram of the NMEA183 to RS232 9 Pin D type serial port connector 


Settings in seaPro have have been changed
The wiring connections have failed, due to corrosion, or fatigue.

Your GPS is not  working/ The GPS system is down/ You have altered the GPS settings  
Using an active NMEA 183 cable incorrectly

seaPro  settings have been changed.

For seaPro  
Select “NMEA monitor window” from the “Window” option on the main menu,
Press the pause button, and look for a position sentence, these start with the following 

Note which one you can see (the first two characters may be different such as II)

Select “Setup” from the main menu, then “Nav properties”, and then “NMEA Rx”.
Tick the NMEA sentences that appeared in the NMEA monitor window .  

Note:  Check that you are sending more than one position sentence.

For seaPro lite
Select the Configuration , menu and then View NMEA. Look  to see if you can see the position sentence (as above)
Close this window, and select the NMEA properties menu
If you saw the GGA sentence, tick the differential box (This does not mean you have differential GPS
just that you are receiving the GGA sentence).

If GGA sentence is in use, you must also ensure that your GPS set is also sending the VTG sentence, as this contains GPS Speed and course information (SOG and COG).

Otherwise if you can see the RMC sentence tick RMC option otherwise tick the VTG option.

The wiring has failed, either due to corrosion, or fatigue.
Check the GPS wiring Diagram (use the diagram supplied with your cable)
Check the cable using a multi meter or  continuity checker and the following Diagram.


Pin Number



Receive (Rx) i.e. signal from GPS (+ve)


Transmit (Tx) i.e. signal to GPS (+ve)


Common signal ground (-ve for TX and RX)





Your GPS is not working/ The GPS system is down/ You have altered the GPS settings
Please ensure the GPS is sending the correct sentences and is set for NMEA183 V1 or 2 and 4800 BAUD rate

Using an active NMEA 183 cable incorrectly

If you are using the active NMEA183 cable without an external power supply you must also set the Power cable option.
This altered in the the Setup->Serial menu


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