First of don't buy the ES127 for a couple of reasons. Raymarine runs about a three year life cycle on a product line and maybe another three years of serviceability after that. The ES is already a year and a half old. Think stale bread.
Also every ES we have had in the charter
fleet mounted outside has lost
the touch screen
at about a year old. Raymarine has made good on all of them but it is a PIA.
Buy the new Axiom it is not much more expensive and is a very nice plotter. No buttons on points of entry for water
on the surface. As for pricing any dealer on Amazon will likely be as cheap
as you can buy at the retail level. Raymarine is running a rebate right now.
Other wise your wish list looks good. You need to draw the Seatalk
NG network out. You will need a multi plug
at both ends of the back bone. One at the pod or mounting location for the outside plotter, instrument, and autopilot head
. Then another inside. If you go with the Axiom you will need an NG to nema2000 cord as the new Axiom line is Nema not NG. You also will want to be able to hook GPS
up to you VHF
calling so you will likely need a nema cable fro that as well.