Join Date: Aug 2006
Location: Arlington, VA
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dog, Bosun, et. al...
I think you missed his question. From it's phrasing, and from his response, I think he's taking some sort of course or exam.
1. you're using U.S. or Canadian charts;
2. you're asking about a question on an exam;
3. you still have your Valiant 37 and got it OK to Lake Ontario :-)
Most buoy locations are marked by a dot...like a thick period...at their base. A few, like private marker buoys, have a small circle at the base of a diamond to show their location. They are also generally in the shape of a diamond, not a triangle. The charted location of the buoy is indicated by the dot. Lighted buoys are indicated by circles or teardrops in color, generally purple/red. The colored circles are centered on the dots.
I know of no chart symbol with two circles. Sometimes, two items may be very close and if the scale of your chart isn't right -- particularly on electronic charts -- it may appear that one buoy has two circles.
When plotting a course directly to a buoy, you'd use the dot.
dog, Bosun, et. al are correct about not depending too heavily on buoy positions in the real world. They can move on their chains in deep water. They can be blown off course. They can be mis-plotted. They can have been moved, and your chart just doesn't show their new location yet.
Still, despite the caveats, in relatively shallow water I've found that buoy positions of U.S. buoys along the East Coast are generally dead smack balls-on accurate (an industry term). The Coast Guard takes great pains to ensure that they are, and they do a damned good job of it.
However, as ever, your mileage may vary :-)
Last edited by btrayfors; 04-10-2009 at 05:45 PM.