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Quick Tips for Running in Fog

Need to press onward despite limited visibility? Here's what you need to know.
Grand Banks Fog

We all get caught in fog at some point, yet even with chartplotters and radar, the situation can be unnerving. The following quick tips can help you be proactive and react calmly when dealing with fog.

  • 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.
  • 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.
  • Use sound signals. 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.
  • Employ 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. Set up a bow lookout. 
  • Know your electronics. In fog, using your chartplotter and radar should be 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. 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.
  • Know the rules of the road for 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.
  • 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.

Read the complete article, which originally appeared in the May 2019 issue of our sister publication, Soundings Magazine, HERE.

For more tips like this, visit the Passagemaker Pro Tips Archive