When the Fog Rolls In Part I: How to Sail Safely

Ask any offshore cruiser or racer about fog, and it’s likely they’ll have a story. Fog is not an uncommon condition, and it generally makes things interesting. Our experts share tips for safely navigating and sailing through fog.


Before we dive into the sailing tips, a quick note about how fog is formed may help you to better forecast it. There are a handful of different fog types (NOAA explains them here), but essentially fog occurs when moisture is involved with differing air and sea temperatures. So when warm, moist air moves across cool land or water, the moisture in the air will condense. Similarly, you’ll also get fog when you have a warm body of water that comes into contact with cool, dry air. Pay attention to unseasonable or drastic changes in temperatures, and try to find a spot where the water and land or air are similar temperatures. 

Many weather forecasting services include fog in their predictions; however, it’s still a good idea to pay attention to the conditions that make it most likely to occur. If you want to learn more about forecasting fog, spend some time on It includes a wealth of information on all things weather-related.


With the potential to create major issues for sailors, fog can make it hazardous to be on the water. But if waiting is not an option, all is not lost. Here are tips for sailing through fog or in any limited-visibility situation. We’re going to look at how your senses can help you navigate harsh conditions and what you need to do to be seen and heard.


It is important to be seen and heard when sailing or boating in the fog. When visibility is reduced, the safest place to be is out in the open, where you can see as much as possible. Depending on the fog layer, the greatest point of visibility might be low to the water or as high as the tip of the mast. Don’t be afraid to move around to find a better vantage point.

In the cabin, stationary, and behind glass might sound like the safest place to be, but it can actually be very dangerous. Sound is distorted when you’re in the cabin. Something that is right in front of you may actually sound like it’s behind you and far away. In foggy conditions, driving from the cabin can also be dangerous due to an increase in glare off the glass or screen. Similar to a foggy mirror after a hot shower, glass on the boat can fog up and make it harder to see. Driving from the outdoors and in the open is best for visibility. 

Sailing in fog is similar to driving in the fog, rain, or snow. To be safe, turn all your navigation lights on so it’s easier for you to see your surroundings and for other boats to see you. You also want to reduce glare as much as possible. Just as you wouldn’t drive with your bright lights on in fog, keep glare-producing objects and lights to a safe minimum. When sailing at night in fog, have one or two lights on the sails for your visibility and also to make it easier for others to see you. This could be something as simple as taping a flashlight to the mast and focusing it on your telltales or having a crew member aim a flashlight on the sails. Make sure there are no objects blocking the visibility of your navigation lights, and remember to always have your navigation lights on and to check them often.

Many boats use radar to navigate through harsh conditions and when visibility is low. For crafts of all sizes, consider hoisting one or two radar reflectors so that you’re more likely to be seen on other boats’ radars. 


Hearing is another important sense to employ when visibility is reduced. Remember that wind can carry sound and it may be hard to hear a warning signal from something that is downwind from you. It is much easier to hear something upwind or adjacent to your vessel. Therefore, sailing upwind and reaching are the safest points of sail because the wind carries noise past you. When sailing downwind, sound will be carried with you.

If you’re under power, use it sparingly. The engine should get you up to a safe speed (3-5 knots, depending on conditions) and then get turned off so you can hear any noises around you. Let the boat drift until it starts to lose steerage and repeat the process−turn the engine on, get up to speed, and then turn the engine off. Engine noise or even a conversation between crew can drown out noises coming from other boats, markers, or land, making it hard to adjust for obstacles. 

While it’s important to minimize constant noise, you definitely want a nearby vessel to hear you. The US Coast Guard recommends one long blast of your boat’s fog horn or a handheld air horn every minute so that other boats are more likely to be alerted to your presence. For boats under motor, one long blast is sufficient. For those under sail, one blast followed by two short blasts is the correct signal. Be sure to review the USCG rules to refresh your knowledge of signals being made by other boats in low-visibility situations. 

If you decide to anchor and wait out the fog (the safest option), be sure to make two long blasts every one or two minutes, depending on the amount of traffic around you. 


Smell can tell you a lot about your environment. For example, the smell of fish can alert you to a nearby fishing boat. Smell can also help you identify the approximate location of something that may not be making noise. A fixed channel marker, for example, will make little-to-no noise, but it does smell like bird droppings. Your sense of smell can help you navigate in fog. 


Note how the air feels on your skin. If there is a warm mist and the water is cool, travel to where you think you’ll find warmer water. Sail to where the water and air feel more alike. It’s most likely warmer in shallower water, so sail up a stream or near a power plant. If the air is cooler, travel away from the coast to a place where there might be deeper and cooler water. 

Fog can be dangerous, but knowing these tips will help you be better prepared to navigate fog safely. 

Keep an eye out for Part 2 of “When the Fog Rolls In.” That article will focus on using electronics while racing in the fog. 

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