I fish with 2 Echomap 73’s. One on console and one on bow. I usually have a hard time lining myself with structure, and my boat position on the map doesn’t seem to exactly correlate with real time.

 

Would the external compass unit make a difference?  The unit itself isn’t expensive but I believe id have to get a network hub too so just wanted to get yalls thoughts. 

Seems like you're trying to line up the structure from your big motor, and if you're going fast enough the Garmins will pick up heading, but when you slow down you lose heading? If that's the case it probably would.

 

What's your TM?

48 minutes ago, Junger said:

Seems like you're trying to line up the structure from your big motor, and if you're going fast enough the Garmins will pick up heading, but when you slow down you lose heading? If that's the case it probably would.

 

What's your TM?

pretty much. Or not really have heading trying to troll around structure. Hard to tell what direction to troll. 
 

I got a 24v fortrex 

A heading sensor is the answer to your problem.   I’m not a Garmin guy but I’ve never seen a heading sensor that connected via a network interface.  They usually connect via NMEA 2000 so you shouldn’t need a network hub.

1 hour ago, Tennessee Boy said:

A heading sensor is the answer to your problem.   I’m not a Garmin guy but I’ve never seen a heading sensor that connected via a network interface.  They usually connect via NMEA 2000 so you shouldn’t need a network hub.

Good call on NMEA 2000. Looks like you’re right.