I Didn’t See That Coming: Boating in the Fog

Written by Capt. Juan Watson
Written by Captain Juan Watson

Spring is here!

Along with the potential that we can expect to encounter fog. I am not a big advocate of departing into the fog but as a former captain at times I have ventured into “pea soup”. Granted, I had great training, experience and wonderful navigational but you cannot control all the factors when being at sea- let alone when you encounter fog. Getting caught out in fog or heavy rain showers will happen if you boat enough, and knowing what to do when you cannot see your approaching “neighbor” is good seamanship.

When on the water we primarily encounter “sea fog” or the meteorological name advection fog. Simply put, this is formed when warmer moist air passes over a cooler water surface and condensation occurs. The fog will generally dissipate with a change in air temperature and an increase in wind speed.


Navigating in fog can be disorientating- without the sight of land it is difficult to reference your position on a chart. You will likely be relying on you navigational equipment be it GPS, radar or a chartplotter. Knowing how to take a GPS position and plot it on a paperchart should be part of your skills as a boater, even if you have a chartplotter. Know your proximity to dangers  and allow for bigger margins with your positioning as you have little or no visual confirmation. The newer you are to navigating the more margin might be needed. Should the weather forecast call for patchy fog there is no need to take a chance if you don’t feel you are a competent navigator. If you however get caught out in fog and struggling, finding a spot to anchor and sitting it out a while could be your best choice.


When it comes to fog- Rule 19  “Conduct of Vessels in Restricted Visibility”  comes into play. This takes effect when vessels are not in sight of one another, meaning if you cannot physically see the other vessel, this rule is applied. With many smaller vessels now fitted with radar we have greater ability to avoid those dangerous close quarters situations. Rule 19 makes specific reference to detecting other vessels by radar alone and the actions that should be taken. For those who do not have radar onboard, Rule 19 details actions for you to take. In order be effective it is imperative that vessels sound their fog signals at two minute intervals. The rules, if read carefully and understood, provide us with the tools to be safer operators.


To effectively apply Rule 19 you need to understand how to operate your radar. If you have a radar fitted and are relying on it to avoid traffic ensure it is at an appropriate range and is tuned to prevailing conditions. Having it on 12nm range and not tuned correctly you might miss a navigational marker or worse, a small vessel, putting everyone at risk.  The same point goes for you chart plotter. If you have your scale set to cover a large area, specific details/hazards may be missed. I generally like to have the radar and chartplotter set close in range so I can identify if radar targets are possible aids to navigation or other vessels.

If you should happen to find yourself caught in fog or even a heavy rain storm where visibility is compromised here are a few pointers that might help moving forward:

  • Have a checklist with action steps when the visibility is poor. This should cover putting on lifejackets, posting lookouts, establishing your position, turning on navigation lights, putting on the radar (if you have one), sounding appropriate signals, avoiding commercial shipping lanes, etc.
  • Reduce your speed- this is key. Give yourself every opportunity to evaluate the situation and make a good call by slowing down. Doing 20kn in the fog is not justified. Additionally if another vessel is approaching and you unsure as to his intentions or not sure how to proceed STOP.
  • If you are uncomfortable or unsure check you are not in a traffic lane, anchor. It is the prudent move.

In closing if you absolutely have to go, make sure you have a float plan with friends, family or the marina you are heading to. Navigating and avoiding traffic in fog can be challenging for professional mariners with training and experience it is even more so for a couple who has recently purchased a boat and just getting their “feet wet”. So I encourage you take the time to educate yourself, your family and encourage your friends as….I would rather be a good boater than a lucky one!

Juan Watson is a 14-year mega yacht veteran. Currently, he owns and operates Pelorus Yacht Consulting, LLC in Annapolis, MD. PYC focuses on educating yachtsmen and owners.