FOG is a fact of life on the coast of Maine. It is most likely to occur in the months of July and August, but quite common from May through September. The amount of fog varies from area to area, as shown on the accompanying graph, and locally it can be totally unpredictable. Sometimes you will be shut in for a day or two, sometimes a week or more.
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In the western part of the state, the foggiest areas are Halfway Rock, at the entrance to Casco Bay, and Cape Elizabeth. Fog is also frequent around the outlying islands of Matinicus and Monhegan. The farther east you go, the more likely you will encounter it, especially in the area between Petit Manan and West Quoddy Head. Fog is much less frequent as you go up rivers such as the Kennebec and Penobscot.

Fog is formed by warm, continental air flowing over colder waters, causing the moisture in the air to condense. In Maine this occurs when the prevailing southwest summer winds blow off the land, producing a “smoky sou’wester.” Often you will see a distinct bank of fog lying offshore, or it may just thicken around you without warning. Morning fog may burn off by noon or early afternoon.
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In his famous book Summer Island, photographer Eliot Porter describes typical conditions for a foggy day. “A day that starts with a glassy bay and a clear sky, but with a white band of haze barely obscuring the southern horizon—the kind of day that promises to be warm—is a day to avoid. The faint white blending of sea and sky... usually indicates offshore fog that will come rolling in as the prevailing southerly afternoon breezes spring up....”
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Coping with Fog. If you are planning a trip to Maine’s outlying islands or to Grand Manan, the best time to avoid fog is during or after a period of northwest winds.
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Although fog requires alert seamanship and careful navigation, it is not the end of the world. In light or patchy fog, it can be an exhilarating experience to find your way from buoy to buoy, occasionally catching a glimpse of an island or headland to confirm your track, all the while sharpening your piloting skills. But when fog shows signs of shutting down thick and heavy, then it is good to be safe in port. Break out the books and card games and settle in. This is a rocky and dangerous coast, and it is no fun to be out there cruising in zero visibility, GPS or no GPS.
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If the fog closes down while you are at sea, get a good visual fix before everything disappears and head for that safe and easy-to-enter harbor you had in mind all along. Keep a careful dead reckoning, making allowance for current which can be judged by observing lobster buoys. Take your time and use all your senses, especially sound and smell. Set a bow watch. Use your depthsounder to confirm your dead reckoning.
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If you have electronics onboard, make sure they are up and running before you are engulfed. It may take several minutes for your GPS or Loran to lock on to strong signals. Program your waypoints before you need them. And your radar will be easier to read in unfamiliar waters if it is on before all your visual references disappear. Click here for a discussion of navigation electronics: GPS, Loran, and radar.
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Run for buoys with sound, either under sail or power. Sail has the advantage of being silent; power can help you run straight courses and get across areas of crosscurrent faster. Remember that fog often distorts the direction of the sound of a bell or horn.
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When sound buoys are scarce, navigate by heading toward bold shores (Great Wass Island Down East and Mount Desert are examples). You will hear the waves breaking and probably see a dim white line of surf through the fog in plenty of time to tack offshore again.
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One of the greatest dangers in fog is being run down by another boat, and, even in Maine, there are plenty of them out there. Your best insurance is to move slowly, listening for the sound of engines. Have a good radar reflector aloft and sound your horn regularly.
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If you are running a course that is a thoroughfare or if you are heading for a buoy that marks a major turning point along well-traveled route, be especially aware that other boats are likely to be searching for the same mark and their courses will converge with yours as you draw near it.
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Here are a few observations: Fishermen aren’t likely to be running specific straight-line courses unless they are heading in or out. Lobstermen are still wheeling around their traps, and draggers are steering along bottom contours. Fishermen are not likely to be sounding their horns, and they are often too busy to see you as a blip on their radar.
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Cruising boats, too, seem reluctant to blast their horns regularly. You may see a large yacht materialize close by and then vanish without so much as a sound. Even if they have seen you on one screen or another, not using a horn is a mistake. If you have radar, do not assume that every blip on your radar screen sees you as a blip on theirs. Likewise, those of us who don’t have radar can’t assume that everybody else does, even when we are flying our radar reflectors. Horn signals provide a warning and a sense of what is nearby, and even in this age of electronics, they can prevent a collision.
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In areas of heavy traffic, commercial or otherwise, monitor VHF channel 16 for securité calls (see Communications). Or in busy areas, make one yourself. The securité call (pronounced “say-curitay”) is made to all concerned traffic and describes a vessel’s position, course, and speed. Nearby vessels should respond, switch to another channel, and make arrangements on how to pass each other safely. For example: “Securité, securité, securité. This is the vessel Intrepid off Portland Head Light and inbound on course 340 magnetic at 6 knots. All concerned traffic please identify. This is Intrepid standing by on channel one six.”
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GPS has made a great difference in low-visibility navigation. Most boats that go out regularly in thick fog depend on satellite systems. They are most useful in fog when programmed with the positions of significant waypoints, but the very programming can be fraught with human error. Program carefully and in advance.
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Radar, of course, is of great value—some would say indispensable—in fog, both for navigating and avoiding collisions. It is used by most fishing boats in Maine and, increasingly, by pleasure craft as both its size and price have gotten smaller. We cruised in Maine for over 10 years without radar, but we now appreciate the security it brings. In a pinch, radarless boats might meet somebody with radar they can follow. See navigation electronics for more details on GPS and radar.
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