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Running In Fog

What to do when you’re pressing on in restricted visibility.


Moisture dripped from the rigging and the sky was a thick, creepy gray. As the bottom methodically came up on the depthsounder, I said to my mate, “Let me know when you see the beach, okay?”

Soon his reply came back from the bow. “The beach! Oh my God, I can see people walking on the beach!”

We all get caught in fog at some point, yet even with chartplotters and radar, the situation can be unnerving. Good seamanship practices can help us to be proactive and react calmly in changing conditions, when it’s especially important to increase situational awareness and remember the rules of the road.

Before you get underway, listen to the weather forecast. If you are already socked in, it may pay to stay where you are until the fog lifts. If you are underway, you might see the fog bank looming ahead, giving you time to prepare for it. Monitor VHF radio channels 13 and 16, where you may hear others discussing the weather. Remember that there is no shame in turning back. Sometimes it’s just prudent seamanship.

It can be tempting to stay in the wheelhouse watching radar, but try not to stay glued to a screen.

It can be tempting to stay in the wheelhouse watching radar, but try not to stay glued to a screen.

If you’re pressing on in fog, then reduce the boat’s speed, turn on your running lights, and start your sound signals. What speed is safe? One that lets your vessel take action to avoid a collision, and stop with a distance appropriate to the prevailing circumstances and conditions. Assess the traffic density, especially on busy waterways, amid moored vessels or in narrow channels. Take the effects of wind and current into consideration, and know the proximity of navigation hazards. Also know the water depth, which might limit your ability to maneuver.

Then there are sound signals. Why use them? Not every boat has radar or an AIS transponder. A power-driven vessel making way should sound one prolonged blast no more than two minutes apart. If the boat is stopped and not making way, then it’s two prolonged blasts. (A sailing vessel motoring with sails up is considered a power-driven vessel.) Vessels not under command, restricted in ability to maneuver, sailing vessels under sail alone, and boats engaged in fishing or towing should sound three blasts: one prolonged followed by two short blasts no more than two minutes apart. A simple rule for most of us is that if we hear one prolonged followed by two short blasts, stay clear.

To identify the oncoming boat, use your senses to try to get a general idea of the bearing and relative movement. Use whatever electronics your boat is equipped with to sort it out. The bigger the vessel, the deeper the tone of the foghorn; if the horn sounds scary and has a steady bearing, then you are in a scary situation.

By all means, call for extra help when the fog gets thick. Setting up an extra watch allows one person to be at the helm, concentrating on electronics readouts and radio broadcasts, while another person is looking out and listening.

There’s no substitute for a bow lookout. I know someone who came across two fishermen sitting on top of an overturned boat in the fog, only because the bow lookout reported voices wafting through the pea soup. The lookout heard the fishermen yelling for help, but the crew didn’t see them or pick them up on radar. I know it’s tempting to stay in a cozy wheelhouse watching the radar and chartplotter, but don’t remain glued to the screen. Step outside occasionally and use your faculties.

If your boat is new to you, then get familiar with your electronics before fog rolls in, so that using the chartplotter and radar are second nature. Practice in good weather; compare what you actually see with what is shown on the screen. Learn how to adjust the radar to read well in various environments. A radar can miss some targets completely, especially if it isn’t adjusted correctly.

While running in fog, if you haven’t programmed your route waypoints, then set a safe “go to” waypoint on your chartplotter. Doing this will reduce distractions. Don’t hesitate to drop to a lower radar scale for more accurate resolution, or to scale up occasionally to get the larger picture.

Be wary of other boats that are likely using the same buoy as a waypoint. Electronically guided collisions are fairly frequent, and small craft don’t always present a good radar reflection. What does your boat look like on others’ radar? Ask a passing skipper how far away you were when he first picked you up on his radar. Do this a few times, and you will understand your own characteristics as a radar target.

Pilot your vessel defensively. Even if your boat is not outfitted with AIS, you can still see who is around you. The Marine Traffic app downloads broadcasts of AIS signals of nearby vessels to your phone or tablet, as long as your device is in cell signal range.

Different rules of the road apply in fog. Only when vessels are within sight of one another do steering and sailing rules determine which vessel is the stand-on and which is the give-way. COLREGS Rule 19 is the only steering and sailing rule devoted exclusively to conditions of restricted visibility. It states that in these types of conditions, every vessel must take action, and every vessel must proceed at a safe speed, ready to maneuver.

Specifics on evasive maneuvering are clear in Rule 19. If you spot another vessel by radar alone, then determine whether a close-quarters situation exists or is developing. Take action early to avoid the risk of collision. “When such action consists of an alteration of course,” the rule states, “the following shall be avoided: an alteration of course to port for a vessel forward of the beam, other than for a vessel being overtaken, and an alteration of course towards a vessel abeam or abaft the beam.” If you’re altering course for a vessel forward of the beam, make a large alteration so it will be readily apparent on the other vessel’s radar.

If a risk of collision does exist, then every skipper who hears another vessel’s fog signal forward of her beam, or who cannot avoid a close-quarters situation with another vessel forward of her beam, shall reduce her speed to the minimum at which she can stay on course. She shall, if necessary, take all her way off and navigate with extreme caution until danger is over.

Use your VHF radio to communicate so there is no chance of misunderstanding or target misidentification. Potential problems in restricted visibility can be resolved by announcing your location and intentions. Commercial operators, in particular, are usually grateful to hear from you.

In fog, reducing speed gives you time to think and react. We were once suddenly set upon by heavy fog in a North Carolina river without the luxury of radar. We announced our location on VHF radio, ran up an extra radar reflector, set a bow lookout, and started sounding the foghorn. Marker by marker, we watched the depthsounder while looking for a place to get out of the channel to anchor. Suddenly, a powerful sportsfisherman bounded out of the fog on our quarter, overtook us at a stupefying speed, and disappeared like a rude apparition into the fog on our port bow. He made no effort to reach us by VHF radio. A minute later, still flabbergasted, we heard a grinding sound, followed by metal screeching. Then silence. We crept ahead and there he was, high and dry on a sandbar. Miraculously, no one was hurt.

We surmised that the cavalier speed was justified in the operator’s mind because of overreliance on his radar. Radar is terrific in restricted visibility, but running in fog requires knowing how to use all the tools available to you. They include a good dose of common sense and caution.