Well said, that gives me a perfect frame to say that the inherent complication in handling the ship's trajectory is how rapidly the trajectory may need to compl

Well said, that gives me a perfect frame to say that the inherent complication in handling the ship's trajectory is how rapidly the trajectory may need to completely change, contrasted against the reaction time of the vessel itself. The OOD is estimating a best trajectory given an analysis of the navigation constraints and the behavior of every possible contact in the vicinity. Orders at every level of detail are possible at any time... from 'resume best course for point "X-Ray"' to 'allaheadflankfullrightrudderbraceforimpactport!'. That is the point of resistance to most levels of automation past 'ship's wheel mirrors rudder angle' and 'engine order repeater indicates desired engine rpm'.