IT’S STRANGE how ordinary people
sometimes suddenly become infatuated with the idea of buying a yacht and
sailing around the world. The first question they ask, before they actually
plunk down any money, is: “How safe is it?”
Well, it’s as safe as you make it,
of course, but I’d say that it has become significantly safer in my lifetime,
which is, admittedly, quite a long time. And what has brought about this
significant change? Satellites.
Thanks to satellites, two of the
greatest safety factors for small sailboats crossing oceans, or even plying
coastlines, are Epirbs and GPS. If I had to choose one as the greatest aid to
safety, I’d have to plump for GPS. Epirbs are wonderful at getting you rescued
after you’ve gotten into trouble, but GPS is what keeps you out of trouble in
the first place.
It seems inconceivable now that
anyone would attempt to cross an ocean without GPS, but many thousands of
people did it before the rocket scientists got good enough to send up
satellites. I well remember the first time I navigated across the South
Atlantic to Rio de Janeiro on a racing sailboat.
I relied on dead reckoning for the
first couple of days out of Cape Town, but the time came when I had to take the
sextant out of its box and demonstrate to a skeptical skipper and crew that I
knew how to handle it. I was the only one aboard who had any idea of how to
reduce a sun sight, and to tell the truth it wasn’t much of an idea, since I
had been teaching myself from Mary Blewitt’s little book, and I’d never taken a
sextant sight at sea before.
My first effort produced a position
that was a long way away from my dead-reckoning position. It was, in fact,
about 15 degrees away. That’s about 900 miles. I was horrified. I didn’t let
anyone else see my workings and I didn’t tell them anything while I checked and
re-checked and consulted Mary Blewitt again.
Nothing seemed wrong with the
figures, which made me even more anxious. I began to wonder if I could
dead-reckon all the way across the ocean. Then, out of the blue came one of
those rare bolts of brain lightning. Fifteen degrees was the amount the sun
traveled in one hour. I had used Cape Town time instead of Greenwich Mean Time
when taking the relevant figures from the Nautical Almanac.
I reworked my sums and the new
position came out reasonably close to the dead-reckoning position. The skipper
and crew were satisfied, and I was very smug. I had no more trouble all the
rest of the way to Rio.
Years later, just a few years back
in fact, I was singlehanding in the Pacific, running down the west coast of
Vancouver Island, British Columbia. I ran two miles offshore for the whole day in
dense fog. I saw nothing but one startled seagull sitting on a raft of seaweed.
I was navigating with a handheld GPS, of course, plotting my position on a paper chart every
hour. My nice sheltered anchorage turned up just where I expected it to be, and
lo! it was in bright sunshine.
I would never have dared to do that
40-mile trip in the old days before GPS. These days, we have all become accustomed to having our position available
on demand at all times in all conditions, and few of us realize what an
incredible change this has made to small-boat navigation. I still regard it as
a miracle, and not a minor one.
Today’s
Thought
Miracle
comes to the miraculous, not to the arithmetician.
— Emerson, Conduct of Life: Worship
Tailpiece
Two houseflies met on the ceiling of
a luxury apartment.
“Aren’t humans strange?” said one.
“They sure are,” said the other,
“but what made you mention it?”
“Well, I was just thinking — they
spend a small fortune building a lovely ceiling like this, and then they go and
walk on the floor.”
(Drop by every Monday, Wednesday,
Friday for a new Mainly about Boats column.)
3 comments:
One of my favourite things about GPS is the reactions you get when its workings are explained to someone for the first time.
Somewhere around the point where you say "And this is the calculation to correct for the difference in the speed of time itself between your position and each satellite's position", there's usually a long pause. Followed by some variant of "This is absolutely incredible."
It is indeed absolutely incredible, Matthew. The whole GPS thing, I mean. And I can hardly believe the equipment needed to work it out and display the result is small enough to fit in the palm of your hand. Or even smaller in some cases. I wonder what Capt. Joshua Slocum would have thought of it. You don't even need a one-handed alarm clock to help you find your longitude these days.
John V.
I casually consult GPS on land-bound trips on the interstate, and get cheesed off when it is not INSTANTLY available.
Post a Comment