Hello there Tony A. West (formerly of Florida, if I'm right), and welcome aboard!
The mysterious eclipse. For myself I've decided the shadow was caused by the starship Tzadkiel, with her sails wide open.
As for the intelligence behind this action: it may be as "accidental" as the miracle of the flying cathedral, that is, it wasn't specifically planned by human/Yesodic entities; or it may be planned, in which case we have as candidates Tzadkiel, OB&F (as you pointed out), and the sailor Severian sliver (after the fatal fight with the dragon--so maybe we should call sailor Severian "Beowolfe"?) who is probably walking around on the ship right now.
(Hmmm. If that "death by dragon" smacks of Beowulf, then where would the Grendel be . . . ? Ah! Baldanders, of course! Doesn't get his arm chopped off, true, but does get his "arm" the mace destroyed, and then escapes down the water hole to the Grendel-mommies, the undines . . . )
=mantis=