Sea Orienteering

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I recently had the opportunity to help a friend take a 25-ft boat down the Intracoastal Waterway from a point near Annapolis, MD, to Belhaven, NC. A number of analogies to orienteering became apparent as we spent two days navigating our way down the Chesapeake Bay. This bay seems a lot bigger when you are at wave level several miles from either shore than it does on a road atlas! Of course, there are no contours, reentrants, rock outcrops, etc.; the only permanent features are buoys often several miles apart.

The shore was too distant to distinguish detailed features, so navigation to a specific destination involved going from buoy to buoy, similar to going from control to control on an O-course. The nautical chart, analogous to an O-map, shows locations of buoys and their numbers (control codes). Our route choice was simple: we took the most direct route to the next buoy to minimize fuel, since the boat gets only 2 mpg. In the old days, this would involve attempting to maintain a compass bearing determined from the chart. However, effects of cross winds and currents required frequent reassessment of your position (using a sextant and chronometer) and subsequent corrections to your compass bearing. I had hoped to try this but found that both my hands were needed at all times just to keep myself aboard as our small boat was tossed by 3-4 ft waves!

Fortunately we had a gps plotter into which we could program each day’s course prior to leaving shore. This is analogous to marking controls on an O-map and making route choices before starting an O-course. The gps showed a little image of our boat on a screen and its orientation relative to the direct route to the next buoy. Even the effects of wind and currents failed to confuse this little marvel; it constantly updated our bearing. Still, when the buoy popped up in the distance over our bow, there was that same satisfaction one gets when first spotting the control on a long leg of an O-course.

We always checked the buoy number. In a few cases, the number had been changed from that shown on our chart, and occasionally a buoy was missing! There is an analogy here to sloppy course setting in orienteering. However, we could be certain of our position by reading latitude and longitude from the gps. These were given to 2 decimal places in minutes, corresponding to 61 feet in latitude. I thought of the sea captains of yesteryear and wondered how the course of history might be different if they had gps navigators. A few of our “controls” were buoyless, just coordinates where we needed to make a change in direction. (Are there any “bagless” controls in orienteering?) The gps also gave us our speed in knots. Our two days on the bay were rough, and after a few hours I was as tired as having run an O-course. Later, on the coastal rivers of NC where shore features were visible, I found my map-reading skills quite useful for navigation and faster than using the gps. After the experience, I will say that I much prefer traditional land orienteering! Grover Everett (gwe@ku.edu) August 05, 2001

-- Grover Everett (gwe@ku.edu), August 05, 2001

Answers

I realized later that a "bagless" control in orienteering occurs when some jerk steals one after the course is vetted. You know you are there, but there is nothing to confirm it.

-- Grover Everett (gwe@ku.edu), August 08, 2001.

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