December 2016 – Salty John : The Blog

The sun was still low in the east, just peeking through the tops of the trees. The wind hadn’t got up yet and the surface of the small bay was a mirror. The reflection of the water disturbed by my oars dappled Adriana’s hull. I marveled again at her lines; that sweeping sheer, the elegant transom, the curve of her bow. Carol appeared from the cabin and looked for me, shielding her eyes; she found me and waved. The dinghy nudged the sand and I shipped the oars, Henry jumped ashore, darted here and there, sniffed, pissed against a felled tree trunk and then stood rigid, looking back at me, tail wagging, anticipating. I stepped out and pulled the dinghy a little way up the shore, found a piece of driftwood, an old tree branch, and hurled it along the beach. Henry dashed after it, snatched it up, dropped it, savaged it and then ran back to me with it in his mouth. I tried to take it from him but he wanted to fight over it. I grabbed one end of the branch and lifted, he wouldn’t let go, his little legs pedalled wildly in the air but his jaws were firmly clamped. I lowered him back to the ground, released my grip on his branch and he dashed off with it, triumphant.

I looked out at Adriana now bathed in the morning sun and was a swirl of emotions; happiness, pride, trepidation. Today we would set sail on an adventure, an odyssey. Our course would take us from this small anchorage in a creek on Chesapeake Bay to points south; to Florida and then to the Bahamas, Hispaniola and the Caribbean.

A journey of a thousand miles begins with a single step – Lao Tzu

The BBC is today carrying the story of a new record wave height for the North Atlantic, nineteen metres, or about sixty-three feet, measured by an oceanographic buoy. A few years ago I heard a report by the Irish Met office of a wave off Donegal that measured in at over twenty metres, sixty-seven feet. The Irish Met Office says the buoy that measured that wave is 11km off the coast; it too was generated in deep water by persistently high winds. Whichever claim is actually the record, they’re both pretty big waves and I wouldn’t like to meet either one in a small boat.

By the way, these are wave heights measured by buoys, there is a report of a wave measured by a ship which was a staggering ninety-five feet.

The probable maximum height of wind waves is around 80% of the wind speed. So, a 50 knot wind blowing over an area of ocean with unlimited fetch would produce a maximum wave height of about forty feet. This height is achieved after it has been blowing for a day, having doubled in height since the first four or five hours of the storm. Further maximum wave height increase is more subdued, it takes two days to get that wave up to fifty feet in height.

The average wave height in a storm is about half the height of the top ten percent of waves and one third of the highest wave. So, if the maximum wave height in our 50 knot blow is forty feet, the top ten percent of waves will be about twenty feet and the overall average will be about fourteen feet. It doesn’t sound so bad when you put it like that, does it? Except that you still have to survive those forty-footers.

I don’t suppose anyone would argue with the proposition that the wheel is the most important invention in the history of mankind.

I do realise that some folk think it was the thermos flask:

“The thermos flask! That only keeps cold things cold and hot things hot!”
“Yes, but how does it know?”

Even so, most don’t seriously doubt the impact the wheel has had on mankind’s development. And I don’t think there’s any doubt the compass is up there with the wheel as a significant invention.

The compass was discovered in 11th century China when someone realised that a lodestone suspended from a thread always pointed the same way. What a ‘Eureka’ moment that must have been!

Unfortunately the Chinese marketing organisation of the day didn’t immediately see the navigation application as worthy of pursuit, seeing more potential in the Feng Shui application. So property developers concerned with the spiritual well-being of their building’s occupants, rather than explorers, were the first beneficiaries of this new technology.

Eventually, however, word spread of the lodestone phenomenon and the compass was put to proper use and the rest is history.

Then came GPS, but that’s another story.