You should replace the plotters, radar, and GPS. They are hopelessly out of date, can't use modern charts
, and can't do AIS at all. You will waste a lot of money
trying to buy charts for the plotters, which are only small areas for the old RL plotters. The performance of the old Pathfinder radar is very poor compared to modern ones.
The good news is that it's not all that expensive. And you do NOT need to stick with Raymarine if you don't want to. The plotters will take data in NMEA0183 form, which your ST70's output (I think even without an adapter). You could buy a couple of 7" B&G Zeus plotters and a 4G radar for only a couple-three grand. One thing to watch out for, however, is pulling the radar cable -- might require having the mast
Your wind, depth
, speed, and pilot can all stay if they work
. All that gear
is quite usable. You might miss interfacing the pilot with the plotter for nav mode. So it's a simple upgrade, not that expensive, to a Simrad
pilot computer and some control device -- like a Triton. Or analogous from Raymarine, Garmin, etc.
One thing I highly recommend upgrading is GPS and fluxgate compass
-- they are not that expensive and the modern ones are far better. The Simrad
GS25 (for example) only costs $200 and is just incomparable to old GPS receivers
-- it gets Russian GLONASS and European Galileo satellites as well as GPS, uses all the differential high accuracy systems, and will give you rapidly updated position with accuracy of usually around 2 meters.
is key to autopilot performance. I used to have a pilot like yours and it was fine. I use an Airmar H2183 which has a three-axis gyro in it -- greatly improves pilot performance and radar overlay. I bought this four years ago -- there might be something better out now, so you should do your own shopping
Add an AIS black box, and you will have AIS data on both plotters and generally available on the network.
The new gear
is hooked up by NMEA2000 networking, which is extremely simple to install. You can grow the network as you later add modern devices. Meanwhile the old stuff can interface with the new network via the plotter via the plotter's NMEA0183 listener port.
Later you can change out depth, speed, and wind for modern NMEA2000 devices, and they will hook right up.
Good luck and let us know how you get on.