NavList:

Bob Bossert, your wrote:
"U.S. Great Lakes Charts of Michigan and Huron were Polyconic, not Mercator. Over 120 years ago, Polyconic was choosen for these two lakes because they are primarily aligned North-South, versus East-West. One of the reasons given was that Bearings on Polyconic charts for North South aligned bodies are more like what you'd see on the water versus Mercator."

Fishy... Those "explanations" sound like local lore. The first part appears to be invalidated by polyconic charts of Lake Superior and Lake Ontario beginning in the late 19th century and lasting at least into the middle of the 20th century. That second part "more like what you'd see on the water" is especially problematic --again that sounds like "local lore".

So what's the explanation then? Why not the same standard for Great Lakes charts as coastal charts from the same era? Tough to say without some serious archival research. Maybe that exists and has been published? Something to consider: Inland US charts, including lakes, were prepared by different authorities (Army Corps of Engineers, for example). They chose projections based on their own standards, typicallly standards chosen for land mapping, and similarly they included scales in statute miles rather than nautical miles. You can explore a vast archive of historical US charts here: https://historicalcharts.noaa.gov/.

You noted:
"I just downloaded some of the new (Sept 2025) ENC NOAA charts for Lake Huron and they appear to be Mercator"

What app/software are you useing to display those charts? One of the advantages of ENC (vector) charts is that they have no native projection (raster charts, by contrast, are similar to scans of old charts and so they carry the projection that was used to create the original charts). Your ECDIS software can be set to display with different map projections of vector charts, right? 

You concluded:
"What are the African countries proposing to replace Mercator?"

Sigh... How quickly the point of this gets lost... NO. This is not about proposing a new standard for navigation charts. It's about the absurd application of the Mercator projection as the standard global map projection in primary internet resources.

Perhaps a few million people worldwide are exposed to practical navigation charts. Among those, perhaps a few tens of thousands understand the ambiguity of map projection: the impossibility of transferring a globe to a flat plane. I posted sample global map images from Google Maps, Bing Maps, etc. With few exceptions, the global Mercator projection is dominant. This is an accident of history, but the implications are enormous. As an estimate, something on the order of four billion people, half the world's population, have been exposed to these wildly distorted charts. This is something like a thousand times as many people as those who use practical navigation charts. 

Frank Reed