Steering 1

Marathon, FL
No LL

Since I'm not sailing today, there is time to blog about a few boating basics. This is for the benefit of my non-boating readers.

Two basic things confound almost everyone until he or she is really accustomed to boating. First, is the specialized jargon like port and starboard. Second, (tomorrow's topic) is the fact that boats steer from the rear rather than the front like a car does.

Cars and bikes pretty much go the way the front points. Boats and airplanes don't. Boats and airplanes must cope with wind and currents that make them drift to one side or the other.

A novice boater steers from point A to point B like a dog swims across the river. A dog just points his nose at point B. The winds and currents sweep him downstream and he must constantly turn to keep his nose pointed at B.

A duck compensates for wind and current and swims a straight line from A to B.


A real live boater always swims like a dog. Therefore we have to invent a bunch of non-simple words to describe his current status.

• Heading is the direction the boat's nose is pointing.
  
  
• Course is the line from A to B. This is where we would like to go. The course is what you might plan on paper before leaving.
  
  
• Bearing is the direction from the boat to B. You determine bearing by pointing at your destination B while en route.
  
  
• Track is the actual direction of the boat's motion. Engineers would say that it is tangent to the actual path. Determine your track with a GPS. When you make the track match the bearing , you have exactly compensated for wind and current drift. Back in the days before GPS and out of sight of land, determining track was black magic and took lots of skill and experience.
  

If a boat really did move like a duck, then his heading would be constant and just enough to compensate for the wind and current. More important, the the course , bearing and track would all be the same thing and we would not need so many words.

On a boat out of sight of land, the only non-GPS way to determine direction is with a compass. But compasses do not really point to the North Pole, they point to the magnetic north pole which today is somewhere in the Yukon Territory. Therefore on a boat you may hear about true course , heading , bearing , and track but more often we speak only of magnetic course , heading , bearing , and track . The difference between the two is called variation, which is up to 18 degrees in places I sail.

Our USA nautical charts sometimes show courses from popular points A to points B. All the ones I have label those courses in magnetic degrees. When we got to the Bahamas, I was fooled at first. After some confusion, I noticed that the courses were all labeled in true degrees.

No wonder things get so technical. All of this stuff seems unnecessary and anachronistic if one had an electronic GPS chart plotter, and is willing to bet one's life on it not failing. With a chart plotter, all you have to do is to see point B on the map shown on the screen. The plotter rotates things so that the boat's track is straight up. Then all you have to do is steer until point B is at the top of the screen. It's that simple.

On our chart plotter, in addition to the map, we always display bearing , track , speed, and speed-made-good. Speed-made-good is the component of track in the direction of bearing, in other words, how fast are you making progress in getting to where you want to go.



No wonder electronic chart plotters are so seductive. They are overwhelmingly convenient and easy to use. Even when you know that your life may depend on those old fashioned skills some day, it is hard to maintain the mental discipline to prevent atrophy of those abilities.