Garmin to factory speedo

[RaceCarRich]

2005 Searay Sundeck 240. Dash has Smartcraft layout (speedo left, multigauge center, tach w multimode display screen right).

Have Garmin Chirp 40/50 Series which has a connection and cable for NEMA 0183 communication.

Is there an easy way to connect the speedo to the NEMA cable from Garmin to get speed from Garmin’s GPS?

 

[RaceCarRich]

Nobody knows?

 

[Scott Danforth]

look at the speedo, it is either a pitot tube or a gps type.

if its a pitot tube type, it operates on water pressure
if its a GPS type, it already has a GPS reciever

 

[RaceCarRich]

I was under the impression that on my boat the pitot tube feeds a sensor in the engine compartment which sends a non-GPS derived electrical signal to the speedo. Does this make sense?

 

[dingbat]

I was under the impression that on my boat the pitot tube feeds a sensor in the engine compartment which sends a non-GPS derived electrical signal to the speedo. Does this make sense?

Makes sense, but chances are it’s l feeding the speedo with a digital or analog signal.

GPS data is tranfered via bus communications

 

[RaceCarRich]

Ah. So no way to easily convert I suspect?

Well it was a nice thought while it lasted.

Thanks

 

[Scott Danforth]

If you have a pitot tube, its most likely run straight to the gauge