I think you might be reading a bit too much into it, ICT.
As a former mariner (merchant, not naval), I must admit I'd not previously encountered such an instrument.
Like most who've been following this thread, I too, have been intrigued by the possibilities.
A Wind-over-Deck indicator is high up there on the list, but OzBob's post, citing the Admiralty Manuals, has tentatively won my vote.
The apparent asymmetry still has me scratching my head, though.
No doubt, someone will be along soon with the definitive answer (including the name of manufacturer - and date) so that we can sleep at night.