Instrument Predicament

[LarrySmith]

Recently purchased a Hatteras 52' Sportdeck with two C140w displays, Raymarine radome radar (direct connect to C140w), and a ST60 instrument.

Below deck there is an Airmar P79 (with unconnected cable 6-pin ( under the helm) and a thru-hull bronze triducer that is currently connected to the ST60 (speed, temp, depth) but it does not work and controls are locked. Depth is always at 54 ft and temp is off by 40 degrees, no speed data. The paddle wheel is totally destroyed.

I would like to add a raymarine AIS class B transceiver and replace the ST60 with an i70s MFD.

The autopilot is an Simrad Robertson AP20 which connects via nmea to the C140w

I'd like some recommendations on what to do with the Airmar p79 as I'm not sure what that 6-pin connector is, and would like to replace the thru-hull triducer.

Additionally I was wondering if I could leave one of the C140w displays in operation (use the other as a spare) and get a newer display to replace the C140w.

All of the existing Raymarine equipment is directed connected to each other, no real backbone is currently in use. The master has the Radar and nmea connection and a direct connect to the other C140w.