Monday Ship Mysteries: Figuring out just where the hell you are on the seas (aka the longitude problem)

Thanks to advances in technology, notably the global positioning system (GPS) of satellite navigation, we take it for granted that one can determine - to a reasonable degree - just where in the world you are at any given time, be it on the seas or on land. The GPS system was initially put in place beginning in 1978, though it only became available to non-military users around 1984. It was the brainchild of two American scientists, Ivan Getting and Bradford Parkinson, who came up with the idea of allowing US naval vessels to communicate with a series of satellites orbiting above the earth in order to pinpoint positions more effectively than had previously been available. (The Russians also developed a similar system, called Glonass.)

The advent of GPS was as important as the internet in making truly universal information available to one and all. In the century prior to GPS, radio beacons and other electronic aids helped navigators in direction finding, but these were crude in comparison to today's tools. One could always use a sextant for celestial navigation, though this piece of equipment is useless if the skies are overcast.

But all of these tools to mariners - as well as other predecessors like the astrolab - have focused on the issue of determining one's longitude on the face of the globe. It’s always been fairly easy to determine latitude, how far north or south you are on the planet: at noon, local time, on any given day of the year, the Sun above Anchorage, Alaska is in a different position than if viewed in Mexico City. The real problem was always figuring out where the hell you were in terms of longitude: at noon in Philadelphia the Sun is in about the same position as if viewed at noon in Denver.

For mariners, this came to a head in 1707 when four Royal Navy ships floundered on the Gilstone Ledges off the Isles of Scilly, killing almost 2000 men. The cause was discovered to be bad navigation techniques, so a few years later a reward of £20,000 was offered to the first person to come up with a dependable means of plotting longitude (the sum was equivalent to £2 million today, or about $3.8 million American).And everyone knew that the only way to ascertain longitude was by standardizing the measurement of time from a fixed point on the planet.Being a British competition, the point decided upon was the Royal Observatory in Greenwich.Quite simply, someone had to come up with a dependable clock, which had not existed until this time.

This led to a flurry of activity as individuals came forth with various solutions to the problem, some more bizarre than others. One of my favorites was a macabre operation utilizing a mystical element called the “powder of sympathy”.The theory went something like this: you first convince someone to let themselves be stabbed with a knife. Removing the knife from the wounded victim, you then sprinkled the powder of sympathy on the blade.This would cause the unfortunate subject to feel pain again, in a voodoo-like manner. The proponent of this theory suggested gathering a bunch of dogs, stabbing them with the same knife and placing the animals on British ships. At noon each day in Greenwich, the knife would be plunged into a bowl filled with the powder and the dogs would all yelp in pain, no matter where in the world they were. Thankfully, this idea was rejected by the Board of Longitude (and one can only imagine the reaction of animal lovers were this bizarre idea have proven effective).

As the top minds in Britain and Europe struggled to come up with a solution to finding longitude at sea, it was a lowly carpenter from Yorkshire who would best them all. John Harrison began to tinker with clocks in his spare time and then became obsessed with developing the perfect timepiece for mariners. His eventual result was known as the H4, a silver timepiece the size of a pocket watch that in 1761 became the first dependable chronometer and solved the longitudinal problem once and for all. To this day it still keeps time in a display case at the Royal Observatory. And, at 1300 hours (1:00pm) in Greenwich, an aluminum time ball still drops from the tower above Harrison’s clock, so that any ships moored on the nearby Thames River can set their chronometers.

Thanks to a carpenter from Yorkshire who doggedly set out to solve this mystery - and eventually claim the Board's prize - maritime navigation became easier to do, and the fruits of his work have been passed down to landlubbers poking at their handheld GPS units. It was a clock that solved the problem, a "chronometer" to professional mariners, and every merchant vessel sailing the seas to this day still carries one in the wheelhouse, as well as at least one sextant (just to be safe).

The bulk of this post comes from my first book, "Ocean Titans: Journeys in Search of the Soul of A Ship". For more on John Harrison, visit the National Maritime Museum's site (see here).