Navigating in fog is very much like flying on instruments. And just as with instrument flying, lack of visual references will often play tricks on your senses. The difference is that mistakes on the boat are not apt to be as final as when you are pilot in command of an airplane.

In the olden days, before long-range position fixing, you were dependent on dead reckoning, and sometimes audio clues from other vessels and their foghorns, or the signaling devices on navigation buoys and light houses. But fog sometimes bounces sound in strange ways and the direction from which you thought you were hearing that bell or horn might not be accurate.

Of course now we have GPS, chart plotters, and radar to help us figure out what is going on. But even with this, it is still possible to make mistakes – especially if you lose orientation. So rule number one is to reduce cruising speed. This gives you more time to assess the data in the nav station, and more time to react if you need to stop or quickly alter course.

In terms of watch keeping, you will want to be sure the radar is properly tuned, and that the watchstander is capable of interpreting radar data. If there is any sea clutter, it will tend to mask other targets. Some of those targets may not be keeping a good watch, and could be running too fast for the existing conditions.

Some years ago we were cruising in Maine, in thick fog, as is typical in the summer. Even though we had a really good Furuno radar with a four-foot (1.2m) open array antenna and a chart plotter, we were moving cautiously from buoy to buoy, checking each off on the paper chart as we worked our way into Boothebay Harbor.

Our visibility was limited to a boat length – we could see just beyond our bow. As we drifted slowly up on a buoy (out of gear) we noticed a shape directly ahead of us, to the right of the buoy. It was a Grand Banks trawler, dead in the water, trying to get a fix on their location. If they had been aware of our presence they could have touched Beowulf’s bowsprit – it was that close. We backed up, turned to starboard, and ghosted around them. They probably never saw us. Had we been going even three knots we’d have put our bowsprit right through their stern windows.

The radar was on, of course. But because the trawler was stopped close to the buoy, it and buoy looked like a single target.

Excluding Maine, the amount of fog we’ve actually had to deal with has been minimal. Alaska has its share in the summer. But it seems to come and go. These three photos were taken as we ran down the south end of Baranof Island. The fog would sock us in for a while, then lift and show us these wonderful shapes. And allow us to practice our instrument piloting.