Historic climate data revisited - 5 - live polar maps

Here are the maps promised at the end of the last post c/w description in that post:

Historic climate data revisited - 4 - polar is POpuLAR

[Update: Part 5 will be the last installment as mentioned at the bottom of this blog-post]

Having explored polar maps here, here and here, was it ever a delight to find one of the earliest maps in that same projection! In This Is the World's Largest and Oldest Map, Culture Trip report how David Rumsey recreated a digital copy of a 1587 map from Milan in no less than 60 pieces:

Historic climate data revisited - 1 - circum-Antarctic

[Update 2: this series has full CC BY-SA 3.0 class notes here
Update 1: please see a mirror project for the Arctic in Part 2.]

With ongoing debates whether Antarctic ice in increasing or not, and its effect on climate change, we must avail ourselves of as much data as we can. If historic climate data is at hand, not only do they get scarcer going farther back, but 1880 also marks a time prior to which their reliability falls off.

So having mapped climate data off tall ships captains logs from 1750 to 1850, I wondered how far south they sailed, and how much they augmented historic climate data around the Antarctic?