You have no GPS, no compass, no chart, and its a dark, cloudy night - can you find your way home?
In this day and age, navigation has become so darn easy that most of us have forgotten how to do it without electronics. The rest of us never learned. Gizmos like Chartplotters and GPS-equipped cell phones lead us along to our destinations with ease---giving us a false-confidence that will surely be shattered sooner or later.
You think those electronic devices are infallible? That theyll never let us down? Not likely. In fact, according to the DOD several nations (including China, Russia, and North Korea, among them) currently have the technology to jam GPS signals at will. And in 2009, GPS outages were reported (along with air-traffic controller equipment disruption, pager interference, ATM malfunctions, and cell phone blackouts), in New Jersey. The cause was eventually discovered to be a truck driver using a home-brewed jammer to avoid paying tolls on the New Jersey Turnpike. Even nature has the ability to bring our satellite-based navigational know-how to a halt; several times in the past sunspots have interfered with GPS signals, knocking out the system in one part of the globe or another for hours at a time. And with the peak in sunspot activity predicted for 2013, theres a good chance your GPS screen could let you down. Or... maybe youll just drop your cell phone overboard, right before your chartplotter goes on the fritz.
So, what are you going to do if and when one of these things happens? How will you get home? Even if you know how to navigate by starlight, what will you do if heavy cloud cover keeps you in the dark?
The very best navigational tool you have onboard is your eyes. Unfortunately, most of us have become so accustomed to setting waypoints and staring at LCD screens that we often fail to bother to really look around---and more importantly, know what were looking at.
Along most Texas coastlines, be it on the Gulf or along a lake, there are artificial lights within view when the sun goes down. Radio and cell towers, oil rigs, bridges, and buildings all give us something to focus on, and navigate by. The question is, do you know what is where? When the sun goes down, will you realize that the dull yellow light off to starboard is the one you want to head for, not the bright one thats actually two miles farther away? In other words, your situational awareness can make the difference between finding the boat ramp, and running into a deserted marsh. Every time you leave a dock or launch your boat, you should take a close look around and take note of those light-providing features you might need in order to return home.
How can you know where youre going, if you dont know where you are in the first place? You cant. Unfortunately, taking a fix, which allows you to pin down your exact location on a chart, is another important task that many modern boaters dont know how to do. Using a compass, you can take bearing to a visible and significant landmark such as a tower, point of land, or river mouth. On the chart, use the compass rose to make a line that runs down the same bearing, through the landmark. Choose at least two other landmarks, make the bearing lines for these on the same chart, and the three lines will intersect at your position.
Not so fast, you newly-minted navigators. We mentioned up-front that you might not even have a compass. What then? Basic navigation and survival skills demand that you know how to make one.
Making a compass is a lot simpler than most people realize, and although it may not be as accurate as the real deal, it will at least put you on the right path. All you need to do is magnetize a small, straight piece of ferrous metal. A needle is ideal but in a pinch you can straighten out a fish hook. To magnetize it, stroke the dull end 100 times in the same direction against a magnet, which you can find on most boats in the stereo or VHF speakers. (Forget that the old wifes tale about stroking it against wool or silk to build up a static charge; this wont actually help the needle point to the north). Then rest it on or push it through the center of a round piece of cork or foam, which you can find on the grip of any fishing rod. A small foam plate will also do the trick. Float the contraption in a bowl or bucket of water, and the pointy end of the needle will rotate to north.
A compass is, of course, of limited value if you dont have a chart. Especially if you need to navigate around an unlighted point of land, or shallow flats that you know stand in the way. And since were preparing for the worst, now were going to assume we dont have that chart. Maybe it got blown overboard, youre on a friends boat and he never bothered with paper charts thanks that false-confidence we were talking about earlier, or perhaps you just plain forgot it. The bottom line is, youre going to have to make one. But instead of just drawing a bunch of lines from memory, you need to first draw equally-spaced horizontal and vertical lines; essentially, give it meridians. Then reconstruct the shoreline or channel as best you can, using the lines to measure distance. If you think theres a straight stretch of shoreline for three miles, for example, use each line to measure out quarter of a mile and then draw the shoreline through 12 lines.
Now, youre ready for dead reckoning. First, identify your approximate position on the chart. Lets say you need to travel along that shoreline for two of the three miles, and then turn 90-degrees to starboard to enter the creek you departed from. Use your compass to find the direction you need to travel in, then take note of your speed and the exact time. With some quick basic math, youll know how far youve traveled during any period of time and can judge when to make that turn to starboard. Lets say that since its dark out and youre feeling your way along, you keep speed down to eight miles an hour. That means itll take you 15 minutes to get to the point at which you need to make your turn; mark your position every five minutes to keep track of your location in case you need to stop or alter speed, and when you reach that third mark, use your make-shift compass to get the direction of your turn correct. If theres a strong current or wind, dont forget to take that into account.
Now your situational awareness comes into play again. If you paid attention to the location of the tallest structures on the horizon when you left, looking at the lights you now see on the horizon will help you judge your course.
Used on their own, no one of these techniques is likely to get you home. Far off lights can be confusing on the water at night, distances are very hard to judge, and its easy to forget whats what after a long day on the water. A home-made compass isnt going to be nearly as easy to use as the real thing, and both fixes and directions of travel are probably going to be a bit off. A home-made chart, naturally, is bound to be inaccurate. But when you put all of these together, youll have a fair shot at reaching your destination. And when the chartplotter wont work or your cell phone fell into the drink, thats whats going to matter the most---in fact, it may be the only thing that matters at all.