Cmap wide map for Furuno or Garmin map for 73DV

[Fishstix]

I have a Garmin 73dv that came programed w/17000 lakes. Problem is in the fingerlakes it is way off on location and it does not show bottom structure I know is there. {Cayuga Lake}  I see they have joined forces with navonics and are supposed to be more accurate. I have not seen any feedback yet.    Around $150 for a new chip.

  I also have a Furuno GP1870df w/antenna that I could use as a stand alone GPS . I am not  familar with the Cmap chip. How accurate are they in the fingerlakes? Around $260 for the chip. Anyone running a 1870 with a new chip?

 

Anyone had experience with either of these? I fish Cayuga and Seneca most of the time.

I like to scoot along the dropoffs