The Fourth Empire's missing ships
There is much point to this analysis but don't get too bound up in its arguments and conclusions. I don't want to give anything away, but consider the following:
(1) We've never said how much of Battle Fleet was normally in mothballs and how much was on active duty. Would it not have been reasonable, however, for said mothballed units (assuming, of course, that there were any <g>) to be put back into active service when a disaster like the bio-weapon got loose among the systems of the Empire?
(2) Mother was put on stand-by and into stasis by the last emperor of the Fourth Empire very early in the Empire's death throes. I would therefore caution readers against investing too much certainty in analyses which Colin made based on the information Mother was able to give him, as that information was, by definition, extremely incomplete. (And, of course, while I would never want to denigrate Colin in any way, it is always possible that he leapt to a wrong conclusion. He's done that once or twice before, you know.)
(3) You might want to consider what might be the logical last action of a CO who knows his or her ship has been contaminated with a bio-weapon lethal to all life forms, against which there is no known defense or antidote, and for which he/she had no data upon which to estimate its probable life span. Obviously a lot of those COs took their ships off to Urahan, but as has been pointed out, all the units of the Urahan ghost fleet put together were only a teeny-tiny percentage of Battle Fleet's total strength.
I don't think I'll offer any more than that just now. It's too much fun to watch you guys wondering what's really going on to spoil it by coming right out and telling you.David