Where on a sailboat would you find a broad-seam?
Send your answers to cruisingcompass@bwsailing.com. A winner will be drawn from the correct answers and will win a subscription to the digital version of Blue Water Sailing.
Congratulations to Sid Nathan, Padstow, England, who did some homework to answer last week’s Mindbender question. “According to Wikipedia and other sources, the first person to create a grid on a map was the Greek philosopher Eratosthenes in the third century BCE. Another Greek philosopher in the same era, Hipparchus, was the first to use trigonometry to find a position on the grid. Both relied on the idea of latitude, or distance from the equator, that was developed earlier by the Phoenicians, who used astronomical observation –celestial navigation– to determine their latitude. Determining longitude to get an accurate fix was not possible until German mathematician Gemma Frisius proposed using time differentials to measure a distance east or west from a prime meridian. But time keeping was inexact at sea until the 1750s when Englishman John Harrison invented a highly accurate chronometer that could maintain Greenwich Mean Time anywhere in the world and thus provide navigators with the time differential needed to calculate longitude.”
