With the arrival of the Fall fog season a few safety tips for boating in the fog are in order.
Before the fog sets in, make sure you have charts and a compass on board. A GPS is also good to have, a handheld will work fine, make sure there are spare batteries. A compass is very important because a straight line can not be driven in fog without help from a compass, radar (if you have shore features to use for navigation) or GPS. Some people say “just watch the wake” fine and well, but watching the wake is not immune to small changes and variations and only helps to steer in a straight line, if you need to change to a new course watching the wake is not too helpful and you need another reference such as a compass or GPS.
Many small boaters think a mile of visibility is fine. However they might not be thinking of freighters and ferries which can move at high-speed. A vessel coming out of the fog a mile away gives only a few minutes to get out of the way. Yes the larger vessels use radar but many recreational boats don’t show up well on radar.
In Puget Sound and the straits of Juan De Fuca you can listen to or call VTS to find out where large vessels are and their speed (Ch. 5A north of a line from Nodule Point to Bush Point on the west side of Whidbey Island or north of Possession Point for the east side of Whidbey Island and Ch. 14 south of those points). You can also tell VTS who you are, where you are and speed, that also tells the big boats where you are. Listening to the VTS is always prudent when boating in their vicinity, and is a great night time tool also.
What to do in fog
- Know your position, mark it on a chart or chart plotter
- Turn on navigation lights
- Slow down, not only to not hit other boats but watch for junk in the water. Remember the Colregs require”a safe speed so that she can take proper and effective action to avoid collision and be stopped within a distance appropriate to the prevailing circumstances and conditions.”
- Post extra lookouts, move a lookout to the bow if possible, use every means available, sight, sound (listening), smell and any other means available
- Use the proper sound signals:
Powerboat, underway, making way, Prolonged – blast at not more than 2 minute intervals
Sailboat, underway, making way, Prolonged – Short – Short – blasts, at not more than 2 minute intervals
- Have everyone put on a PFD (Lifejacket) if they don’t already have one on
- If you have radar on board assign a trusted and skilled crew member to monitor the radar continuously.
Fog / Impaired Visibility Tips
Rotate lookouts, having two forward lookouts at the bow is prudent if there is enough crew.
Lookouts should look and listen for ANYTHING AND EVERYTHING, sounds from aids to navigation, breaking waves, floating material in the water, rocks, piles, shore line features, remember Anything and Everything.
Navigate by following a depth contour line. That might be a bit longer than the straight line but by watching the depth sounder and following where you are on the chart has gotten many mariners home. A friend never fails to tell his adventure when fog dropped down on him, he set a compass course toward the shore, turned on a depth contour line and followed the contour line for a couple of hours and got home safely.
One of my instructors, (who has a 100 ton license and many miles in command) when operating around VTS lanes, likes to run down the right edge of the VTS lane and be very very predictable, his theory is the big boys know what they are doing. On the other hand he has almost been ran over several times when going along the shore by crazies, in small boats, on a plane, visibility of a few boat lengths, can’t see where they are going, and probably using GPS for navigation.
Quick question, you hear a single prolonged blast about every 25 seconds, what type of vessel might you expect to find? A question I ask in class quite often. My reply, a small power boat underway, making way with a nervous captain and no watch on board. Remember the “at not more than XX minute intervals”
Idle the engines down to bare steerage or stop the engines so the lookouts can hear better.
The transmission of sounds in fog may be erratic, it can be difficult to determine the direction they are coming from.
If your boat does not have a permanent radar reflector (a sailboat race rules requirement in Puget Sound), get out the portable reflector and raise it as high as possible.
UPDATE 12/30/2013: Received the advice below from a friend that now lives in Florida
Hi Mike! Just read your article about cruising in fog.
Most small boaters do not have their compass adjusted or have a correction table available. Some boats deviation I have observed to be significant.
In lieu of adjustment or a correction table, I was advised by an unlimited ton Master to do the following, and so suggest you could advise others to also.
At least for the routes across or along the sound they use most often, they could log, and/or have a separate list of, the MAGNETIC courses on their boat to and from their destination so if they are on their way and encounter fog, they will have the courses they need for THEIR boat available WHEN they encounter fog underway. I used to log and record these along the way, and then turn around half way there to get the correct magnetic courses for the return also with both deviation for my boat and variation at that point on earth incorporated just by reading the compass courses and writing them down.
Thanks for supporting boating safety
– c/m –
What you say is true, but pretty much impossible when single-handing. I don’t think I left the deck for more than a minute at a time. Thank goodness my electronics worked well. The only GPS backup I had was my smartphone. I think there are AIS apps for smart phones. I’ll have to check them out.
yes when the count goes down to one you become something like a one armed paper hanger – you used all available methods and from what I saw on your site, you were very alert, why not put Farley up on the bow for forward watch?
Glad you got home safely & had a nice time
Caution on AIS web apps – they may not be real time by substantial amounts. I have heard there may now be premium options for a real-time guarantee, but check.
One armed paperhanger is right even with everything working – consider an autopilot as high priority for maintaining consistent headings while you are doing all the rest, especially to get the most out of radar. And be sure to add that radar reflector to be a consistent strong target for the other guys.
Thanks for the feedback & visiting
I have also read about some limits to web based AIS, also the web based AIS depends on shore stations acording to one of the sites a looked at, so if a shore station goes away there would be a blind spot that you might not know about
I have also seen some cautions about cell phone Aps. on a couple of different places,
Make sure you are a big radar reflection, then the big boys with the way loud deep horns will be extra diligent letting you know they are out there
Oh, I almost forgot. What the hell is a “Small Arms Safety Zone” on a chart? Does the NRA have anything to do with it?
Not the NRA – I think this is the right point
During a class I took this past spring we did a unit on navigation in fog. The text was excellent on the technicalities but I was surprised at one omission.
During another, earlier navigation class, our instructor (a seasoned sailor) emphasized that the first and most important rule of navigation in fog was to carefully establish whether the skipper actually needed to be navigating in fog. The context of the class was for amateur and not professional mariners; the instructor’s point was that it’s rarely the case that a yacht skipper can make a truly compelling case for fog navigation with the risks entailed. Sometimes good navigation means staying on the hook or at dockside.
Very good point, my oversight, and one that is overlooked often
Thanks for the help
I forgot to thank you for your post, which is particularly useful given how our weather knob here in the NW has seized up at the “fog” notch of late.
You be more than welcome, glad I could help you a bit. Go ahead a look around or subscribe, I am slow and erratic at my writing but I take pride in writing useful articles
I don’t have ads on the site, so my “payment” is the page views and visitor counts I see or when someone is helped or finds my information useful – pass a link on to your friends also
Thanks much for visiting and stopping by and commenting
take care & good luck with your boating
Thanks for your post. I had to travel from Friday Harbor back to Lake Washington last September, leaving San Juan Island around 6pm. Impossibly thick fog set in almost as soon as we left the marina. My friend and I piloted our way to Deception Pass relying entirely upon our radar and chart plotter. We were hopeful that our compliment of technology, slow speed and, perhaps, hopefulness that we were the only ones foolish enough to be out there would guarantee a safe passage. Thankfully all three of those, combined with a vigilant watch, secured a safe return. Though, it was certainly challenging going through Deception Pass relying 100% on our chart plotter and the wonder that is GPS. Would I do it again? I wouldn’t want to, but I’m glad we were able to navigate calmly, doing the best we could with the circumstances we faced. Incidentally, we did have AIS integrated into our chart plotter. Happily, no dangerous targets appeared during any part of our journey.
Glad your trip turned out well, remember to NEVER USE A SINGLE POINT OF NAVIGATION!!!
The combination of Radar with Chart Plotter is good as it can help tell you how far off shore you are – but keep in mind that a long beach with a low slope can be very deceptive.
Good point. On that particular boat we only had a single chart plotter / radar screen. Garmin has an overlay feature, so we were able to overlay the radar output on top of the chart plotter to associate radar images with actual (according to the chart) charted masses / land. Going slowly with an observer / listener on the bow was key.
The overlays are the nicest.
I did an entry into one of the harbors in the San Juan Islands – using GPS – the GPS was showing us needing to be in a different position than we were – the owner came up onto the bridge and got all excited about the GPS Chart Plotter and how I was in the wrong position – my response? I pointed out that the safest water was a point 1/3 over from the starboard side of the channel, which was where we went in the deep water – the depth sounder showed that we were in the right place – you are maybe wondering where the GPS would have put us? In the shallow part with maybe a foot under the keel if that.
Thanks for the notes on this, very helpful! I was caught in heavy fog recently and used compass and GPS to make my way home. I always clear the current track on GPS when heading out, don’t take shortcuts and swing wide of lobster pots etc… So that I will have a clear track in case of night and / or fog. Compass allowed me maintain reasonably straight path and GPS confirmed correct course. Did not have a horn will, add before heading out again!
Glad you found this useful, GPS can be deceiving, I have talked to many people that were out in the fog and were almost hit by a small boat, using GPS, but on a plane screaming through the fog in two boat lengths of visibility.
Amazing that people would try and drive that fast when you can’t see where you are going! I was going slow which is where the compass really helped as the GPS does not update heading very well at low speed. What was most interesting was the tendency of boat to drive in a CCW circle? I was almost always port of intended travel line. Assume that has to do with single screw outboard?
In fog the tendency is for a person to drive in a circle, does not matter what kind of boat. I think the straight line time is less than a minute before a person starts to turn. Thus the need for the compass, the same think happens to airplane pilots in a cloud.