Around here, if it really fogs in, it is impossible even to detect the location of the sun. Also, fog is mostly associated here with calm waters. So one's clues regarding water movement and sun and wind can be very limited. One can get into in a real pickle second guessing one's direction of travel if one has been using transits. If you know that your boat tends to weathercock or lea cock it can help a bit in guessing which way it is tending.

I have to say, even though I was in calm, familiar and safe waters, that the one time I was really caught out in serious fog without a compass I became quite certain, not making my intended landfall in a certain time, that I had gotten turned around, and had do discipline my thinking to maintain my course for an extra fifteen minutes. Eventually my mark appeared before me though. What had happened is that I must have slowed down in the fog in order to concentrate on running a straight course.

Ever since I stow my compass behind my seat if it looks like fog, which is rare. Also around here the fog never lasts long, so if in doubt one could always just sit it out and read a book until it lifts.

Watch out for the Flying Dutchman in fog, and other big boats. It can be hard to hear from whence they are coming.

Et