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The Trades and Planet Earth

Posted by Keith on April 10, 2007 at 1:17 pm  

April 10, 2007

24.16N // 146.08W

661 Miles Northwest of Hawaii

Late Easter evening we reached The Trades, and we’ve been on a ride ever since.

Since mariners first set sail, the trades have propelled them to new worlds and home again. Across the globe these winds and currents move relentlessly east to west from south of about latitude 25N, and from north of about latitude 25S, almost to the Equator where, on either side of it, in an area known as the Intertropical Convergence Zone (ITCZ), both wilt into hot, sticky doldrums, above a weak, opposing west-east current.

At our current latitude, the east-west Northern Equatorial Current adds an extra half- to one knot of speed as it pushes us along. Closer to the Equator the Equatorial Counter Current pushes at barely a knot in the opposite direction. Then, below the ITCZ, along the southern trades, the Southern Equatorial Current resumes the prevailing east-west direction.

Above the ITCZ the trades typically blow from the northeast, and below the ITCZ they typically originate from the southeast. Although at 24N we are well in the northern latitudes we’ve been met by 10-15-knot south-easterlies (winds from the southeast). This occurs precisely 37 percent of the time, according the The Pilot Chart of the North Pacific Ocean.

Meanwhile, at this latitude, we continue to receive swells from the north-east Pacific. They arrive with great energy, although the further south we head, the smaller they become.

The result these past two days, as we pursue what is now our 255-degree west-southwest great-circle route to Hawaii, is that we’ve been pushed on our port quarter (left-rear corner of the ship as you look forward) by the persistent trades, and on the starboard bow (right front of the ship) by 8-10-foot swells.

Thus the sea wants to spin us to the south, but the first of our Nordhavn’s redundant Simrad auto pilots has kept the rudder turned against this bias, while our massive Trac stabilizers have minimized yawl.

But by any standard, it’s still one heck of a ride.

The sky to our north is pale blue on the horizon, and deeper blue above, with a few scattered clouds. Earlier, to our south, dark storm clouds stretched almost across the horizon from east to west, and mushroomed thousands of feet into the air. But they’ve dissipated. The trade winds from behind us cause two-to-four foot wind waves with occasional white caps as far as the eye can see in any direction; and the incredible force of the North Pacific still makes itself known in the diminishing swells we encounter on our starboard bow.

We are a speck on the sea. Yes, we are aboard the most seaworthy of vessels, but the ocean, the currents, the wind, the clouds, or any combination of them could sweep us away in a blink. We are nothing compared to the forces of nature.

It is the height of human arrogance to believe otherwise.

As we debate issues such as global warming, it is well that we remember this. Ultimately, the most effective environmentalists – what President Teddy Roosevelt called “conservationists” – aren’t the loudest or most radical alarmists who make movies or write books predicting mankind-caused apocalypse, but serious and objective students of nature’s awesome force, and of the extent to which mankind may from time to time temporarily, often inconsequentially, sometimes importantly, intrude upon it.



1 Comment so far

  1. Dan Streech on April 10, 2007 9:41 pm

    Beautifully said Keith. Perfect. At the end of the day, those of us who love the sea and have experienced the pristine vastness of the open ocean are probably more authentic environmentalists than those “limousine liberals” who robotically parrot a party line that they don’t really even understand.

    By the way. Great show on Sunday. I was just going to cherry pick thru the archive and listen to the parts about the boat and the voyage, but found myself glued to the entire show. The segment about the Chinese Yuan was obviously very interesting to me.

    Thanks, Dan.


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