Jessica Watson, the 16-year-old Australian girl who cast off Oct. 18 from Sydney Harbor on her planned non-stop, 23,000-mile solo voyage around the world, reported on her blog today she has officially re-crossed the equator and is now sailing again in the southern hemisphere.
As her current course at is nearly due-south, Watson took the time to explain to those following her on her Web site how the “great circle route” she is taking is actually shorter than heading directly for Cape Horn at the southern tip of South America.
“The distance (5450 nautical miles) that I gave yesterday as the distance to Cape Horn is the distance in a straight line, but weirdly, we're actually going to be sailing a slightly shorter route,” she began. “I know it sounds really strange, but it's all to do with something called the great circle route and the curvature of the earth.
“I'm probably not the best person to explain it, but as an example, if I were to plot out our course directly to South America, taking into account the earth's curvature, the fastest way to get there would actually be to sail in an arc to the south. Our great circle route, or the fastest way to get to the cape, is to sail south and then gently arc over to the east (5130nm),” Watson wrote.
She also noted that it was easier said, as “there’s all of these annoying islands and reefs in the way … and it’s not like the wind ever just lets us go where we want to.”
As a reminder that Watson is attempting this circumnavigation without any outside help, as well as alone, she wrote that as she was passing the little island of Starbuck, if she wasn’t doing the voyage unassisted she would put in a stop for coffee.
Comments