Forging Ahead In Fog

In adverse conditions, despite a proliferation of technology on boats, the traditional tools of navigation are still important.

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With the twin Lehman diesels warmed up and purring like two well-behaved lions, the crew of the 42-foot Grand Banks Andiamo cast off the docklines and headed out into the choppy, cold waters of San Francisco Bay. Over the marine VHF, a recording of the early morning’s weather provided an update about off shore winds, tides, sea state and atmospheric conditions. With the bow pointed seaward, the boat and crew passed under the red-orange arches of the Golden Gate Bridge on the outgoing tide. A tall, black-hulled luxury liner slipped quickly and noiselessly by, its curious and excited passengers lining the rail and viewing the receding skyline of the city.

Up on the bridge deck, Andiamo’s crew sipped fresh, hot coffee while watching the channel buoys pass astern. A long, gray Navy cargo ship, without a sign of crew aboard, slowly pushed out to sea. The tops of her cargo masts disappeared in the dark, water-saturated air. Awaiting Andiamo about two miles offshore hovered the traditional late-summer blanket of coastal fog. Keeping well offshore, the trawler changed course and headed south toward Half Moon Bay.

While watching the San Francisco shoreline and the Cliff House become intermittently obscured in heavy patches of fog, the crew carefully laid out their course on the chart. With the autopilot, GPS plotter and radar on, the crew stowed the binoculars and took up parallel rules and dividers. Visibility dropped to 100 feet.

The fun work begins

In the warm comfort of the carpeted steering station in the main salon, the crew shed their heavy jackets and caps, rolled up their sleeves and went on instruments. They recorded GPS latitude/ longitude positions on the chart every 30 minutes. They carefully monitored the shoreline and relative bearings of other vessels on the screen of the faithful and hardworking radar. A buoy here, a finger of land or outcropping of rocks there were all carefully noted and checked against the chart.

In the fog, where no visual references are available for the use of a sailor’s traditional handheld bearing compass, navigation becomes somewhat like a blind man without use of his cane or guide dog. The crew was blind, except for the electronic eye of the radar cutting through the dense fog.

With one crewmember on watch, occasionally shifting the cursor to the shoreline or a passing vessel and receiving distanceoff information, the other could relax and listen to music, cook, read or even take a shower, knowing all was well.


According to data from NOAA, West Coast boaters should know how to navigate in the fog. Los Angeles has an average of 92 foggy days per year, while San Diego has 97, roughly one-quarter of the time. San Francisco, perhaps surprisingly, has 108 days of fog, which is 30 percent of the time — maybe less than some people perceive. Seattle’s fog rate is closer to 45 percent of the time, or 165 days, which probably doesn’t surprise anyone.

On being prepared

An idyllic situation? You bet. But what allows that to happen? As we used to say in the U.S. Navy, “Proper preparation is essential to the successful completion of any job.” In the case of coastal navigation, that means having the current charts in the proper scales and the most recent copy of “Notice to Mariners.” A prudent skipper knows where temporary dredging, missing buoys, marine sports events or naval exercises are taking place. The sudden passing of an unexpected fl eet of 100 knot offshore powerboat racers or the appearance of 60 marathon swimmers might not happen often, but knowing about them could prevent some embarrassment or serious injury.

Still-essential common tools such as a lead pencil, an eraser, parallel rules and dividers ensure that courses can be plotted and time and distance problems worked out with a minimum of effort.

While manufacturers such as Raymarine, Furuno, Simrad and others have the most advanced radar and chartplotting capabilities, boaters should always know how to navigate without such instruments.

While manufacturers such as Raymarine, Furuno, Simrad and others have the most advanced radar and chartplotting capabilities, boaters should always know how to navigate without such instruments.

Tending to business

Have the wonders and magic of modern electronics taken the place of old-fashioned navigation and piloting? Will technology such as the increasingly ubiquitous GPS, whose dropping costs have increased access, take the place of common sense? Can we toss our navigator’s tools over the side? Not really.

Skippers must retain the ability to read the chart correctly. What is the proper scale of miles? Are the markings on the chart in meters, feet or fathoms? Are we reading magnetic or true headings from the compass rose? A misreading could put one’s course across rocks that are awash at low tide. Have we recorded and plotted our last course change?

Boaters who have GPS on their boat need to take the time to get familiar with it. The same held true for Loran when it was an essential presence on boats. What features does your particular unit offer? Can you create waypoints? If so, are you using them correctly? Have any been left out or entered incorrectly? Do the course and speed compare favorably with the dead reckoning plot, compass and knot meter?

Years ago, when I crewed on a 27-foot sloop to Monterey from Santa Cruz, Calif., we were completely socked in with fog. We saw nothing until we broke out near the entrance buoy to Monterey Harbor. Our skipper was elated by the performance of his newly installed Loran. Before we shoved off from our dock, he had set in the course and waypoints. It was a job of navigation well done, and the Loran had worked as advertised.

On our return trip, we were once again in fog for the entire trip. As we approached our own harbor, we saw the shoreline between breaks in the fog. We were dismayed to find, dead ahead, a big dredge. It was laying pipeline for a sewer outflow, just offshore next to the lighthouse.

“It looks like we are about 15 degrees off course,” I told the skipper.

“Impossible,” he said. “Always believe your instruments, not your instincts.”

“I agree,” I said, “but we certainly aren’t where we’re supposed to be. The harbor entrance is about three miles to the south of the dredge.”

A quick trip below to the chart table revealed the answer to our problem. Indeed, we were to the north of our destination. The Loran system had done its job well, just as we had instructed it to do — except we had erred by punching in the wrong coordinates for our harbor. It was a minor mistake, and we were in no danger, but there was a high surf running and we did not want to get caught in it.

What about radar? Does it have a built-in warning or scan system where an alarm sounds if a vessel enters the area? Does it have a feature where you can determine if another vessel is on a collision course with yours (if your boat isn’t equipped with AIS)? More importantly, do you know how to use such features, and have you read the operating manual? The more bells and whistles a given piece of equipment has, the more vital the instructions in the manual. You paid for the features, why not use them to their fullest advantage?

Once, while off Ano Nuevo Island, we contacted a skipper friend aboard the fishing boat New Holiday. Wishing to hail him as we passed, we picked up his image on radar and headed in to close the range. With less than a quarter mile of visibility, we plotted our closest point of approach. At the given time, he appeared exactly where we expected him to be. Score one for radar.

Electronic Eyes

While your MFD can display copious amounts of information, do you know how to read it all, and can you translate what you’re seeing to and from a paper chart?

1. Furuno FR8002 Series Radar in Target Fusion Mode || 2. Furuno 1835 Radar in Off-Center Mode

1. Furuno FR8002 Series Radar in Target Fusion Mode

2. Furuno 1835 Radar in Off-Center Mode

3. Furuno NavNet TZTouch Split Screen with Chart Overlay and Radar

3.  Furuno NavNet TZTouch Split Screen with Chart Overlay and Radar


What are the chances a given piece of electronics equipment fails? What would a skipper do in the event of total electrical failure? Because it could happen. How? Well, the equipment of today is vastly superior to that of 20, even 10, years ago. Sealed units and connectors, molded-in epoxy circuit boards, modern components and materials, and other innovations all work to avoid failure. Yet, failures do occur. Just out of Half Moon Bay, our GPS and chartplotter stopped working. Perhaps the equipment was overheated. Maybe it was a power surge. Whatever caused our problem, we received no position information. Nothing we did would make it come back online. Fortunately, we were in visual contact with the harbor. The following day, it worked fine.

Salt water and moisture from condensation both have an insidious way of sneaking up on equipment in the form of corrosion. A rogue wave that hits a boat in a following sea can introduce large amounts of water into the cabin. Given enough water, the electrical circuits can short out. An electrical fire, loss of an alternator or a generator, or dead batteries could interrupt the flow of current in the boat’s electrical system.

What to do?

A vessel’s skipper must know where his vessel is at all times. He doesn’t have to keep a minute-by-minute update of every rpm the engine makes, but he should maintain a running log, including the last position on the chart (in latitude and longitude). In other words, plain old dead reckoning is still necessary and can be fallen back on in case of an emergency or power failure.

Running over a floating log or other object could hole a vessel and cause an abandon ship situation. Letting the Coast Guard know your whereabouts within a few miles since your last plotted position is essential to early rescue. Hypothermia sets in quickly in Northern California and Pacific Northwest waters.

Coastal navigation in dense fog can be easy in today’s world of modern technology. Avoiding problems by taking the precautions of a prudent navigator is still required, however, for safe voyaging at sea.

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