Weather Series: Sailing in Fog & Mist
As with all uncertain weather conditions at sea, developing an understanding is often the best cure to overcome that fear. Knowing what can cause fog, where and when it’s most likely to occur and what characteristics you can expect, such as density and duration, help you to create the best sailing strategy to overcome this potential hazard.
While fog can occur for a number of reasons, generally speaking, this phenomenon appears when air is cooled quickly below its dew point. This rapid change in temperature is often associated with the change in temperatures from night to day, rapid change in temperature due to oceanic up welling and currents, as well as the onset of rainstorms. The length of fog is variable based on the current weather conditions, but usually, as the sun warms, you have a ‘burn off’ effect, or if wind speed increases, this tends to dissipate thick fog.
Should you find yourself sailing through fog, it can feel very eerie and perhaps a little daunting losing the visual aids you typically use to sail safely. The essential rule to safely navigate through fog requires that you identify your position for other vessels, but also that you can identify others too. Select a course that avoids the most possible hazards such as shipping channels or high traffic areas. Travelling at a reduced speed will also give you the maximum amount of time to change course if required.
With the age of modern electronics onboard yachts these days, fog has certainly become much safer to navigate. Utilizing this technology with chat plotters, GPS, high-powered radars and AIS (Automatic Identification System) allows for greater ease when sailing in challenging weather conditions. Adding a slightly oversized radar reflector will also help others to pick up your location on their radar system. Carrying and familiarizing yourself with as many of these tools as you can will aid your navigation at sea in adverse weather conditions.
As with any circumstance related to reduced visibility, it is essential that proper navigation lights are used. For sailboats, this is a port and starboard sidelights (red and green) and a white steaming light. Also, carrying a powerful waterproof spotlight in the cockpit is your best tactic to attract attention quickly if a ship is approaching.
Since the human ear can audio-locate with a surprising degree of accuracy, using an old-fashioned foghorn can be one of the most dependable methods of announcing your presence when sailing in fog. The international sign for a vessel under sail is one prolonged blast (4-6 seconds) followed by two short blasts (1 second each) every two minutes. In addition to this, it is advisable to use your VHF radio using the securité (pronounced “secure-a-tay“) call to announce your position, course and speed to nearby vessels.
It would be unwise to put all trust in modern technologies, we all know that sometimes our trusty technology fails. Have as many eyes as possible on the water as possible when sailing in fog; the more people watching, the better the chance to avoid a potential traumatic experience. With adequate safety equipment, PFD, safety line and wet weather clothing, have one crew member position themselves at the bow, away from the engine noise, to keep watch and to listen for breaking waves, other vessels or potential hazards that might not be picked up on the radar or chat plotter.
Sailing in the fog is not ideal but with the right preparation, equipment and planning it can be done safely!