The Floating Palace is in orbit, so a Broadsword could dock there without requiring streamlining.
Book 2 of Pirates of Drinax, page 261 states,
"The Palace Rises: The Floating Palace is not a
spaceship. It is not even airtight. But if it seems as
though the day is lost, then the palace rises from
the surface of Drinax, gravity-engines howling as
they are pushed far beyond the redline. Atmosphere
vents from a hundred unsealed cracks and hatches.
Gargoyles and statues crack and float away into
the void, forming a short-lived ring of relics around
Drinax. The palace will not survive this last gesture
– but it brings its massive defence cannons into the
battle, which are worth +10 Fighting Strength."
So this would seem to disprove your theory that the Floating Palace is an orbital station as it is not even air-tight.