Longitude (Encore)

Ocean Hazards

Navigating the open ocean has always been fraught with dangers, particularly from underwater hazards like reefs and sandbars. Gary Arndt explains that while Polynesian navigators had advanced knowledge of these dangers, European ships often fell victim to them due to their larger size and deeper drafts. For instance, Sable Island, a large sandbar off Nova Scotia, caused between 350 and 500 shipwrecks.

European navigators weren't so lucky. They had much larger ships that sat much lower in the water. If there was an underwater hazard, such as a rock or a reef, and they were unknowingly to hit it, the results could be devastating.

--- Gary Arndt

Accurate mapping was crucial, but even the best maps were useless if sailors didn't know their exact location 1.

   

Latitude vs Longitude

Determining one's position at sea required knowing both latitude and longitude. Gary Arndt notes that while latitude could be easily measured using a sextant and the pole star, longitude was far more challenging. The British Parliament even passed the Longitude Act of 1714, offering a substantial prize for a reliable method to determine longitude.

The key to determining longitude was time. If you knew the local time and the time at a fixed location, you could determine the difference in time, and hence the difference in longitude.

--- Gary Arndt

The solution involved understanding the relationship between time and geographic location, a concept that revolutionized navigation 1.