Help needed understanding my Raymarine Seatalk -original- system

[cpedw]

The boat (owned for 2 years, dates from 2001) is well equipped with electronics - Raymarine C70 plotter & radar, ST60 instruments including GPS and S3G autopilot, all interconnected by the first sort of Seatalk .

I was surprised to find there's also an NMEA connection to the plotter. After a lot of floorboard lifting and other contortions, I found the NMEA connection is from the autopilot computer, NMEA1 output. I followed that up with a lot of study of the many manuals to try to find out why.

My guess is that it supplies fast heading from the fluxgate compass to the plotter for MARPA. Is that right? Is Seatalk not good enough for the fast heading?

If so, I think I will have to adopt a more complex approach for the AIS I'm thinking of fitting ...

TIA,
Derek

PS the autopilot is far superior to previous ones I've owned - 4000 and 2000 types.

 

[matthewriches]

You’re correct. MARPA needs a 10Hz feed so “fast” as opposed to 1Hz.

 

[denmike]

The compass is likely communicating at 4800 baud, and that's not enough for your AIS. If that's the case you'll need a mux, which can mix it together. My boat also had a VHF connected with the C80 over nmea-0183 to send the location for DSC (this is also running at 4800 baud).

I use a module from ShipModul.