Keep it there at least as a backup! In the beginning its a tool you already can handle, during the time you learn to handle the new unit.
Its also good the let one of the units do the navigating, and the other one dooing the sidescanning job.
And its newer wrong to have two units of ewerything in a boat.
Once when we where going out to our cabin, thats located on an island, my chartplotter shows that boat was going about 45 degrees out of the course. Somethings didnt feel right. My compass and my second gps shows that my direction was correct. Just at this time I once and for all needed the navigation system. It was dark and rain. I couldnt see the coastline att all. I choose to follow my compass.
In a situation like this you get real pist! ( at least if you got your wife on board!)
Later I found out that the fault in my plotter was the electric cable, an lighterconection cabel, that was allmost broke. It seems that when the voltage dropps to low, the the GPS-chartplotter didnt work properly anymoore?
If I had navigated by the plotter, I would for shure, in five minutes, had hit something I dont want to hit.
That was a lesson that shows me, that ewen a good quality unit can fail in a moment when you dont want it to happen!
Kimi...