NAVIGATING IN THE FOG
I originally wrote this paper in Maine while we were waiting for the FOG to lift enough to see our way out of a harbor. The ‘research’ started over the summer of 2003 by talking to other cruising people about how they navigate along the coast in restricted visibility. It continues in 2009 as we meet people, read other articles, update our own electronics and experience more fog. It should be no surprise that we have discovered that everyone handles fog differently. What I initially wrote about was how we did it aboard our cutter MOONESHINE, Since I wrote the first version we have ‘matured’ from sail to power so I now have a powerboat addendum after five seasons of cruising aboard SUNNESHINE our Sabreline 36 Fast Trawler. The important thing to remember while you read this is that I have written about how we handle fog, NOT how you should.
BASICS. We normally have two people aboard, my wife Kathy and me. Our sailboat had a Radar, VHF radio, GPS, Notebook Computer and an Autopilot. It was also equipped with a radar reflector, fog horn, and navigation lights. It seems to be the goal of most electronics writers and designers that all navigation equipment should be visible and operable from the helm. We never quite reached being able to operate everything from the helm, but we did have it mounted so that the helmsman could see it all and, with teamwork, we could change settings without the helmsman/skipper going below.
GPS WAYPOINT MANAGEMENT. We prefer to steer using GPS waypoints not computer chart program ‘point and click’ waypoints. It’s our policy that our next navigation waypoint is always set into the GPS, even in fair weather. It is best if a series of waypoints (route) can be set in before getting underway. A record of waypoints helps make this chore easier. We write the waypoint Lat/Long on our paper charts, either in the margin or next to the diamond waypoint mark we put on the chart. We always chose waypoints on the safe side of navigation marks (buoys) and offset them for several reasons. We do not like to get too close to commonly used waypoints because other boats may also heading there. We have heard of incidents where people actually have hit their waypoints. We also have heard of boats circling the waypoint in a fog, something we don’t want to interrupt! We number our GPS navigation waypoints (01, 02, etc.) and give names to destination and safe haven waypoints (Camden, Belfast, etc.). At the end of each day we delete the numbered waypoints from the GPS leaving only the named places for use another time. We transfer our GPS waypoints to our Computer Chart Program which then becomes a double check of their accuracy. If a waypoint is entered into the GPS incorrectly it is obvious when it appears in the wrong place on the displayed chart. The key to any waypoint system is that all people aboard must know how to use it.
CHART PROGRAM. We use a notebook computer powered by a small inverter connected to a 12 volt power supply and to the GPS. On the sailboat it sits on the Navigation table and is easily visible from the helm, not more than 10 feet away. Changes to this display are made with a mouse that may someday be extended to the cockpit with wire or a remote. We make sure all of this is up and working before we ever get underway. We display the same chart that we have plotted the waypoints on and we use the look ahead feature. This means that we are always seeing the ‘little red ship’ (actual GPS position) on the same chart that is at the helm station. Sometimes the raster chart on the computer is upside down in the look ahead mode but that does not bother us. In fact, we like this relative ‘picture’ because it is the same presentation that we see on our radar where our ship is in the middle and ship’s head is up.
The writers of navigation articles seem to want us to record our position in case the electronics fail but we don’t think that is realistic with everything else that we are doing. If all fails we always know the course we are steering will take us to a safe waypoint while we figure what our next move will be.
RADAR. We normally operate the radar on the 3 mile range scale until visibility closes in. Then we shift to the 1.5 mile scale. Our vessel is in the center and we look at a relative picture with ship’s head pointed up towards the top of the screen. When we pick up a closing contact we place the EBL (electronic bearing line) on it and read the relative bearing and range (either by counting range rings of by shifting to the VRM (variable range marker). After several sweeps we are usually able to establish a bearing drift as long as we remain on a CONSTANT COURSE. At the same time we compare the radar picture with the chart plot display to see if our contact might be a navigation mark. If we do not have a bearing drift we change course early (normally to the right) until we clearly see relative motion towards a CPA (closest point of approach) on our beam. If the contact closes in to a half mile we follow it by shifting the radar scale to ½ then ¼ mile. If we can’t visually see our closing contact and have not been able to identify it as a navigation mark we sound a FOG SIGNAL (one prolonged blast) and slow down until the situation resolves itself.
AUTOPILOT. We steer by autopilot 95% of the time, especially in restricted visibility. “Mike” (our autopilot) steers a CONSTANT COURSE better than we do because he is not distracted. This means that relative motion of contacts on our radar screen is not normally caused by an errant helmsman. This fact alone simplifies the radar tracking challenge more than any other feature we have on the boat. When we dodge a ‘lobsta’ or crab pot marker “Mike” remembers our course and returns to it with a flick of the switch. We do not connect the autopilot to the GPS or Chart Plotter and worry about those who do.
FOG SIGNALS. We have the fog signals written on the side of our air horn with a bold magic marker as a reminder for the person who uses it. We do not sound signals (every two minutes) while underway because maintaining the routine and the noise distracts us from our other chores. We do sound signals when we hear one close by and when we have a radar contact close enough to hear our horn. We have talked to other cruisers who have automatic fog signals (usually built into high end loud hailers). They tend to use this feature as long as it doesn’t interfere with other tasks, like use of the VHF. A dedicated loud hailer with automatic fog signals is something we now have on the power boat so we use it more often.
VHF RADIO. We listen to VHF Channels 16, 13 and 09 on scan. In fog, when we hear someone shift to another channel, we briefly follow since they almost always talk about the weather conditions in their location. We do not issue securite calls but we listen carefully to those that do. They mostly come from commercial or professionally driven (larger) boats. When we hear other sail or power boats give them they often forget to tell at least one important fact (like location or direction of movement). From this observation comes the lesson learned that all info should be written down before issuing a securite call. We have a remote VHF microphone and speaker at the helm. This has changed our cruising more than any single piece of equipment since computer charts came aboard. A secondary benefit of this new radio is that it has DSC (digital selective calling) which means it is connected to the GPS and can send an automatic distress/Mayday signal that includes our vessel position with the press of a button. Another benefit is that the radio display below decks gives us current GPS position which is a lot easier to use than shifting the GPS away from its waypoint function to read/plot current position on a chart or read it to someone on the radio.
RADAR REFLECTOR. Bigger and higher is better. Racing sailboats are required to have at least 6 square meter reflectivity on their reflectors. Other countries (like Canada) have laws that require 10 square meters on all boats. The only way to meet these guidelines is to have a BIG reflector and follow the instructions on how/where to mount it. It amazes me how many people have inadequate reflectors as well as how many do not display their reflectors properly. It is best to have a reflector permanently mounted. Ours (two Davis, one above the other) are up at all times.
“OUR WAY”. Several years ago I read an article in a local Maine publication that essentially said “We don’t go out in the fog. Why do you folks ‘from away’ go out in it?” This made a lot of sense. We don’t leave port when there is restricted visibility (less than ¼ mile). We stay until it clears. If it gets bad after we leave we consider going back into port or seeking an alternate safe haven and anchoring until it clears. This holier than thou attitude changes if we let schedules (like getting to the next partyJ) dictate our movement. We try to anticipate rendezvous and gams by arriving a day early, just for this reason.
If we are sailing when fog closes in we turn the engine and navigation lights on and motor or motor sail slowly on a steady course towards our destination so that we can concentrate on safe navigation procedures.
We do not try to see through dodger plastic or glass windows during restricted visibility. I find that wearing polarized sunglasses helps me see better in fog. I keep a paper towel (Bounty) handy to frequently clean glasses that mist over in the really thick stuff.
Finally, US SAILING has a recommendation in their safety booklet that recommends wearing a PFD, harness and tether while sailing at night and in restricted visibility. This makes sense if you are working on deck since the remaining person might not be able to find you until the fog lifts if you fall overboard.
We made the shift from sail to power in 2005 after 20 years and 85,000 miles of cruising and racing in our beloved cutter MOONESHINE. I figure this has added 15 years to our boating life. We still are spending four to six months aboard while traveling 2-5000 miles a year. 2009 will be our 20th summer to Maine by boat. After four seasons we are enjoying the power of a well built trawler with many creature comforts we never dreamed we would have on a boat.
BASICS. We still have two people aboard. We moved our Dell Notebook Computer and our portable GPS to the trawler along with the small inverter that provides AC power to the computer. We hardwired a remote Dell monitor and mouse on the upper flybridge and added anti-glare hoods to both computer and monitor. These work as well as any daylight capable screens that we have seen, at a fraction of the cost. We find we are using the same basic procedures and techniques to navigate in the fog that we used on the sailboat, with only a few modifications.
GPS WAYPOINT MANAGEMENT. We still are using the same procedures that we did on the sailboat.
CHART PROGRAM. We shifted from Maptech to Nobeltec but we still prefer raster charts even though our new system has vector capability. A bonus here has been that all of NOAA’s 1000+ raster charts of the US waters can now be downloaded free. We have them all on the computer and on a CD that we purchased for $40. The next stage is to use vector charts a bit more and to download them as they become available. Nobeltec allows us to display both on a split screen which is helping us gain more confidence in the vector presentation. We are also adjusting to the fact that vector charts are not upside down when we are headed south!
RADAR. This has been our biggest change. SUNNESHINE had no radar when we bought her so we had our choice. This was not an easy task as the marketplace is a moving target with ever changing options and very little credible comparison of capabilities. After careful study our decision was to go with a 2 Kw Nobeltec digital radar which is compatible with our Admiral Navigation System. It not only is compatible, it is a fully integrated tracking and navigation system. We can overlay radar as well as aerial photos on the chart, all displayed on one computer screen and/or its monitor. We still have the traditional EBL and VRM tracking capability on the radar but we also have automatic tracking and CPA calculation (MARPA). We are able to automatically display DSC positions of other capable vessels and MAYDAY callers.
AIS (Automatic Identification System). We have a small boat version of AIS on SUNNESHINE that identifies and gives us course and speed information of merchant and other large vessels. This is not part of the radar. It has a separate VHF receiver and antenna.
This makes navigating in the fog more exact but it does not make it any easier. We still are looking for bearing drift on all surface contacts and find that we must be confident in our ability to operate the radar.
AUTOPILOT. We have a newer autopilot than we did on the sailboat but we use it the same way by having it steer the majority of the time so that contact bearing drift is caused by relative motion not helmsmen trying to stay on course. We still have not joined the autopilot to the navigation system and worry about those who have.
FOG SIGNALS. Unfortunately we have lost our capability to listen for faint fog signals because of the loud engine noises and our inability to open windows at the lower helm station. Our loud hailer has built in fog signals that can be run automatically, so we use fog signals frequently. We also use the listen feature it has periodically. For backup we have a built-in electric horn and a portable air horn readily available at the lower helm.
VHF RADIO. We added a new VHF radio because we wanted the DSC, loud hailer, fog horn and intercom features that they now have built into them. We have not changed our procedure for listening to Ch 16, 13 and 9 on scan and following other transmissions for weather and contact information. One thing we are very cautious about is ‘The Cat’ Ferry in Maine waters. It proceeds at high speeds (30+ knots) between Bar Harbor and now Portland to Nova Scotia, even in restricted visibility. We follow their radio transmissions and listen with interest to boats in their path exchanging positions with them. If we ever find ourselves anywhere near their path we plan to do the same. We also can see her on our AIS.
RADAR REFLECTOR. We have a single octahedral reflector permanently mounted as high as possible but I am studying some of the newer reflectors that use three Luneberg Lenses oriented for max reflectivity. Reports indicate that they are the best passive reflectors on the market and are worth the price.
NAVIGATION LIGHTS. Reports from trawler owners that LED nav lights can be seen so much better in the fog have convinced me convert to LED. They are great.
“OUR WAY”. We still have the same outlook operating the powerboat that we had in the sailboat. We have learned to use windshield wipers and washers on the glass surrounding the lower helm station which we seem to favor over the fly bridge. Keeping clean windshields and frequently ducking outside to look & listen are important safety procedures, IMHO.
In summary, the powerboat is more comfortable and better equipped than the sailboat but it is only as good as our personal procedures and precautions in restricted visibility. It is still safer to stay in port or anchor out of the way in the fog.
COMMENTS, SUGGESTIONS AND A CONTINUED DIALOG ON THIS SUBJECT ARE INVITED TO