There is a hydraulic driven ram drive for the Simrad Dawg and it works fine and is more reliable than the screwtype linear drives in my opinion. I have owned both types and presently have the Simrad on my cable driven quadrant. I am well pleased with the performance.
how does hydraulic pilot work with non-hydraulic steering? I.e. what happens when you hand-steer? Does the rudder post move and in turn push/pull the hydraulic ram?