Here's a small video motoring through the Maine fog. Not quite Pea Soup in thickness but chicken, for sure.
When I first started sailing in Maine with Laurel and Laurel's parents George and Greta, a big deal was never made of fog. George would always say that fog works out and his running joke while in the fog was usually "Where the fog are we?"
Back then before plotters and GPS were really popular we just worked it out on paper, plotted a course, kept current and tide in mind and watched our time and speed carefully. We also kept our ears wide open. Because if you're sailing you can hear an awful lot in the fog. Like breakers, the swish of swaying seaweed on rocks, bells, gongs and other boats.
Laurel and I did a cruise with her parents in Penobscot Bay and when we awoke to fog one morning George employed his "aim straight at land in the fog method." While this method isn't for everyone it suited George's way of thinking perfectly.
The area we were in was surrounded by deep water islands. George felt that if you plotted a course straight to your final destination, you wouldn't have a way to know if you had strayed off course, if you could confirm some points along the way you could be more confident of your position.
So he plotted straight for the middle of an island. We would sail the course, keeping an eye on the depth sounder and when the island appeared (usually no more than a couple of boat lengths away) we would tack and run alongside the shore till it fell off, then continue on to our next controlled near collision till we made our destination.
As a young lad very mesmerized by the sea and sailing, I just drank this stuff in and when we later did our own first cruise aboard a small 12 1/2 foot sailboat with just our sails, a pair of long oars, a stopwatch, compass, and our senses. George's lessons, adapted a bit, served us well indeed.
I think the most important lesson about this for me was that fog always works out, and armed with that belief, some skills, tools, and a bit of confidence one can venture forth in fog and in life; our near collisions helping us find our way.