You leave the marina in clear air, and half an hour later thick fog closes in around you. In that moment the important question isn't why fog forms, it's when to slow down and turn back. The right decision is made before the shoreline disappears completely, not after.
The best protection starts before the fog arrives. Save your track on the device, set a return waypoint, charge the phone, and spread life jackets among the crew. If you see light fog on the way out, that is the moment to turn back, not when it thickens and the shoreline goes.
Set a clear limit for yourself. If a landmark you could see plainly, a tower, an island or a channel entrance, is gone, that's your signal to stop or turn back. If visibility drops to where you can barely see a nearby boat, this is no longer a trip, it's either waiting in a safe spot or retracing your track.
Slow down before you have to. Speed in thick fog means reaching danger before you see it, with no time left to react.
Our bay is shallow, and fog hides the bottom, moorings and small boats. Shipping lanes run close to where we fish, and a dhow can't stop the way we can. In fog the right call is conservative: slow to the minimum speed you can still steer at, leave more room than usual around anything you see, and listen before you move.
Call someone on shore who knows your plan and your expected return, and tell them you've entered fog. If you're late, they know where to start looking. Don't let "I'll wait for it to lift" become an open-ended decision with no time limit.
If you do stop, anchor properly in a genuinely safe spot, clear of shipping lanes, not mid-route, and give the shore a clear time to expect you.
The B7R app puts navigation tools, sea state and the SOS button in one place, so you can follow your track and report your position fast.
Waiting isn't wrong by itself, but the wind often picks up before the fog clears, and the sea builds with it. What started as a quiet wait turns into wind and chop. If the wind rises or the sea builds while you're in fog, the answer isn't to wait longer, it's to head back or make for the nearest safe shelter.
Give yourself a clear time limit. If visibility hasn't improved by then, or the wind has come up, you go. And head for the nearest harbour you know well, not necessarily a distant starting point you can't see.
With the B7R app you can check sea state before you leave, so you pick a better day and time instead of getting surprised.
The B7R app is free on Google Play, download it here: https://play.google.com/store/apps/details?id=com.q8dm.b7r