without being able to see the horizon, the rig or the surface
If you're on any sort of finals to a rig and you lose sight of it you are going around anyway as per the procedure and back to the bar..
You don't fly on dark and stormy nights. They tried it on the Cormorant A once and it turned into a disaster. Offshore pilots can, when necessary do it, as the evacuation of the Hermod proved; but they are not paid to.
Maybe in the Klondike days of the seventies we did it.
Radalt???? XXXII.XXXIII,XXXIV on a semisub's pontoon leg was good enough.