I have functioning code that I tested with LEDs, I basically made sure the right LEDs lit up for a given analog input from a potentiometer. This however was using 5 inches of wire. My concern is the vulnerability of the voltage inputs on the 50 foot ethernet line to fluctuate with small disturbances ( main disturbance would be the current running in the power line for the ROV).
I have ran a test using 50' of 22 AWG wire as the input line from the pot to the Arduino. The only way I could create a disturbance was by wrapping the line around a power tool's frame (AC engine). I also wrapped the wire around the power tool's power cord but no disturbance was seen in this case.