NavList:

I hesitate to weigh in here because I'm a technician, not an historian.  But, over 35+ years I've stared at a lot of compass cards.  Some observations:

-- It's much easier to manufacture a quarter point card by sub-dividing the circle.  You would need an indexing engine to create a 360deg card.  So, when did indexing engines become available?

-- The term "boxing the compass" did not refer to calibrating the compass.  It was the task of a seaman "naming" all the quarter points around the card.  BTW, there are two versions of naming: one merchant marine, one navy.  Both are challenging.

-- around WW1, the navy needed to quickly train helmsman, and it was easier to order a heading using degree numbers rather than quarter points.  So, the navy transitioned to 360deg compasses.  I think the merchant marine stuck with quarter points for a while longer.  How long?

-- Major compass manufacturers sold combo cards startng early 1900s (ish).  Older (alcohol filled) compasses were almost always quarter points.  Newer compasses phased out the quarter point cards.

So, I may be way off base here.  Adjust my thinking with abandon.

-- 
Robert S. Peterson
Great Lakes Compass
31 N Alfred, Elgin IL  60123  USA
847/697-6491
Compass expertise for Lake Michigan navigators since 1985
email: glcompass(at)astound(dot)net
web: https://www.greatlakescompass.com/