Saturday, September 17, 2011

Update: Dad, Magellan, and Greenwich Mean Time

On a personal note, yesterday marked the third anniversary of the death of my father, Don Earle. Dad was a US Marine during the Korean War. Like a lot of combat vets, Dad didn't talk about his experiences much, but in a paper he wrote for a college class after the war he said:
I was then [summer 1951] selected by my friends and neighbors to enter the Armed Services of the United States, and was chosen by the Marine Corps after vainly trying to get into the Army.  I took my boot training in Parris Island, South Carolina, then transferred to Camp Lejuene, North Carolina for three months schooling in their baking class. After completion of this school, I travelled to California for a four-month refresher course in Infantry Training, to prepare for a year in the lovely peninsula named Korea. I lived a calm, peaceful happy life for the following year then reluctantly I was persuaded to return to the United States where they forced me to take a thirty day leave, then return to Cherry Point, North Carolina where I was released to return to the dreary life of a civilian.
On a geopolitical historical note, this week marks the anniversary of the Battle of Inchon when, in 1950, United Nation forces numbering 30,000 came ashore and ultimately dislodged Communist forces from the South Korean capital Seoul. It was the largest amphibious invasion since World War II. Approximately 1,500 UN and North Korean troops died over the four days of fighting; there were 800 wounded on the UN side alone. A version of this post was originally published on July 9, 2009.

When my father and a few hundred of his fellow US Marines sailed to the Korean War in 1951 on an old Liberty ship, they were split up into two watches."Port watch" would be responsible for galley, clean up, and various other duties about the ship on even-numbered days, and "starboard watch" on odd-numbered days. After more than a week under way, for most of which Dad was very seasick, his watch was suddenly awakened on a day they thought they were going to have off. "We just had the watch yesterday," the Marines of his watched grumbled. "Yeah, but we just crossed the International Date Line," the able seaman shaking Dad awake explained. "It's an even-numbered day again. Now, get to work, Marine!"

The survivors of Ferdinand Magellan's circumnavigation more than 400 years earlier were similarly surprised when they arrived at the Canary Islands and found their calendars off by a day. The ship's log recorded:
In order to see whether we had kept an exact account of the days, we charged those who went ashore to ask what day of the week it was, and they were told by the Portuguese inhabitants of the island that it was Thursday, which was a great cause of wondering to us, since with us it was only Wednesday. We could not persuade ourselves that we were mistaken; and I was more surprised than the others, since having always been in good health, I had every day, without intermission, written down the day that was current.
The International Date Lines follows, roughly, the line marking 180 degrees of longitude, exactly half way around the world from the Prime Meridian, which cuts through the Royal Naval Observatory at Greenwich, thus the term Greenwich Mean Time or GMT. Mariners use GMT to avoid problems like those of my Dad or the Magellan expedition survivors. If you're crossing several times zones in the course of your passage, it's easier to stay on the same time throughout, so many long-distance vessels use GMT or "Zulu" time (each time zone as a letter designation and Greenwich's is "Z, " as seen on the map above). Some vessels, especially military ones, may use Coordinated Universal Time, abbreviated UTC.

Time is important to navigation as well. It's fairly simple to find your latitude using the sun or the stars, but longitude is a problem that evaded mariners for centuries. British clockmaker John Harrison thought that if you compared your current time and the observed position of a heavenly body to a known time and position of that body, the difference could help you determine your position. The problem was having an accurate enough timepiece, which Harrison went on to invent and eventually win a big prize for.

Although these days we're more likely to glance at the GPS to get our longitude and latitude, mariners still need to know what time it is. Official tide and current tables are published using standard time, so we have to take that into account if we're using a local Daylight Savings Time. And if we have to rely on "celestial navigation," it's essential to have an accurate local time.

Dad was probably pretty happy that the navigator of that Liberty ship had an accurate clock, especially when they pulled back into San Francisco Bay a couple of years later. As he told me once: "I'll bet no one was ever as happy as I was to see Alcatraz!"

The photo at top shows Marine Corps Lieutenant Baldomero Lopez leading the scaling of the seawall at so-called "Red Beach" on September 15, 1950. Baldomero was posthumously awarded the Medal of Honor for throwing himself on a live grenade only minutes after this photo was taken.

Jules Verne's hero Phileas Fogg wins the day thanks to the International Date Line in the 1873 novel Around The World In 80 Days. Find it on googlebooks here.

The Royal Naval Observatory is now part of the National Maritime Museum. Find lots of good info about the Prime Meridian, timepieces, Harrison, and more here.

For a good, quick read on the "longitude problem" and Harrison's struggle to solve it (not to mention his subsequent struggle to collect the prize), try Dava Sobel's Longitude. See an excerpt here.

A nice one-page primer on celestial navigation can be found on the US Navy Quartermasters' website here.

For more about the US Marines in the Korean War, see Lee Bergee's 1963 memoir Rendezvous With Hell, James Brady's The Coldest War: A Memoir of Korea (read an excerpt here)and Martin Russ's The Last Parallel: A Marine's War Journal. All present a jarhead's-eye view of the war.

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