When we taped the promo sequence of our Childrens Public Broadcasting hopeful, "Ahoy Archimedes," I signed off with an antique sailing farewell, "Fair winds, a flowing tide, and following seas". This is a farewell in the original sense of “fare thee well.”
Fair winds are those blowing in the direction you’re bound. A “flowing tide” is the fortunate opposite of a “foul tide” (current against you). Following seas lift and seem to carry you – anyone who has tried to make headway in a “head sea” (waves opposing your course) knows what a buffeting, frantic, frustrating experience it can be.
The tide might seem a mega-force acting over enormous areas that has little application to tiny boats on its surface. At sea, yes. Onshore, it is to larf. When enormous areas of water attempt to empty from or fill up smaller areas of water, the resulting water pressure and consequent current can be shocking. Tidal bores in France and in China regularly set up six-foot to eight-foot walls of water moving at the speed of a bus up tidal rivers. The wicked “holes” between Buzzards Bay and the Vineyard and Nantucket Sounds see current twice a day that challenges the bladder control of staunch, experienced skippers. In one of them, Woods Hole, steel ocean buoys six and eight feet in diameter, weighing several tons, whip back and forth in the full flow, appearing at the surface only at one limit of their heavy mooring chains, emerging in a boil of water like sportive dolphins, sucked down again to make the next circuit and rear up at the other chain-limit. Tidal current fills and empties the Bay of Fundy inside Nova Scotia, making a waterfall that reverses directions twice daily, and giving ports at the head of the Bay a tidefall of (a flabbergasting) forty-five feet. To put this in perspective, the tide there would cover and uncover a four-story building twice a day.
When the tidal current runs against the wind, it sets up an unholy chop. At the mouth of the Cape Cod Canal, where the six knot SW current meets a steady twenty knot “smoky sou’wester,” standing waves of eight and ten feet set up in the channel off the Canal’s protective breakwater into Buzzards Bay. Watching a fifty-foot yacht expose half of her bottom, from forefoot to keel, before she crashes into the trough is impressive from shore but truly breathtaking from the deck.
One of the explanations I was making to Kai, a delightful kid who was part of our taping, is that a wave isn't what it seems. A wave is an energy pulse that travels through the water, while any given molecule of water stays pretty much in the same area, moving up, forward and back in a circular or elliptic motion. The water stays put (except for current effects) while the physical disturbance of the water travels on. The wicked surf on many beaches is an amplification phenomenon – the energy of the pulse rebounding from the shallowing bottom when the depth is less than a certain proportion of the waves’ height and period (length or time between crests). The rebounding energy increases the height of the waves without affecting the period, so the amplitude (height) of the wave is multiplied and, eventually, can’t support itself structurally and “breaks” – surf. There are tremendous waves at sea that can be very impressive from a small boat. It's not uncommon in, say, the Roaring Forties (40° south latitude) for seas to reach a regular height of forty feet and their crests, blown by wind, break in “combers.” Breaking waves like this are called “graybeards” in respect and awe. But the period of these graybeards, the length between crests, is dictated by wave physics uncomplicated by bottom amplification and can be a quarter or even half a mile.
In the vast fetch of the sea (“fetch” is the distance over which waves travel and grow) the waves around you may be generated by more than one factor. A storm working up the sea a thousand miles away can send its waves to you, and this “train” of waves (a long set of energy peaks) meeting your local waves at an angle can amplify, diminish, or alter the frequency of your wave conditions. It can be tricky to steer in a “confused sea” like this because the pattern of amplifications and diminutions seems random (which it ain’t).
Traditional oceanography was pleased with its wave theory until recently. Water is, after all, a relatively uniform fluid, so physical laws apply uniformly. Obedient wave equations had been built and confirmed. You seen one wave, you seen ‘em all. Professional bluewater sailors disagreed. Many have faced the phenomenon of “rogue waves,” which were considered folklore until sober reports from supertankers, research vessels, and sea-measuring radar satellites confirmed their existence. It’s now considered likely that, at any given moment, ten mountainous rogue waves are alive and rushing across the World Ocean for hours at a time, some in excess of a hundred feet. In 1943, for instance, the celebrated liner RMS Queen Mary had been pressed into service as a troop ship. She was capable of such extraordinary speed that she needed no conventional convoy escorts but she was sometimes accompanied by fast-moving, sub-killing Navy blimps. The Queen Mary met a a pair of rogue waves, startlingly larger than the “normal” storm waves around it. One wave was photographed from a blimp breaking OVER HER BRIDGE, ninety-three feet above her waterline. Bridge windows were stove in, the bridge flooded, and the Queen Mary, among the largest ships afloat, nearly went down in the battering. She listed 52° for several minutes before she righted herself and continued.
There are mysterious places – the Agulhaus Current off the Cape of Good Hope is one – that also produce rogue troughs, “holes in the sea.” A British warship encountered one in the 50’s, fell into the trough, and kept going down. Lost with all 600+ hands in a few moments.
A tsunami is not a rogue wave. Indeed, the energy pulse of a tsunami can pass under a ship without notice. It’s essentially a huge convex disturbance of the surface, of such a scale that a ship wouldn’t be able to detect it. When it reaches the continental shelf off the shore, however, bottom reflection of energy converts it to a giant, lethal wall of water.
The point is that our World Ocean is
aqua incognita. It ain’t Kansas. It is an arena in which humanly unimaginable forces dwell daily. We don’t know a great deal about the ocean, so far, and haven’t devised a way to live securely on or in it. Bits and pieces of information drift in like flotsam to the shore. Space Travel? Captain Kirk and the Enterprise? Puh-lease. We’ve got places a few miles offshore where no man has gone before.
NOTE: SAILOR FOLKLORE
There is an ancient joke about sailors’ reportage: What’s the difference between a “sea story” and a “fairy story?”
A “fairy story” begins, “Once upon a time…” A “sea story” begins, “Now this ain’t no shit…”
Readers are assured that, within the limits of good-faith research and suppression of poetic license, the above ain't no shit.
BRAXINOSO SPEAKS
As Himself has often said, "No one can love the sea." It's too cold and cruel and unfeeling and dangerous. But it's difficult for a thinking person not to be fascinated or even obsessed by the sea. The cowboys say, "The outside of a horse is good for the inside of a man," and the hayseeds may be right. But ocean fascination and being on the water is good for the heart and mind. Neither Adkins nor I have any pretensions of mastery or even professional knowledge of the ocean. We're shoreside dabblers, coastal sailors with occasional leaps across blue water. I'm glad that neither of us has false courage about the water. One is especially pleased that a romantic like Himself still has a healthy fear of setting out on the face of the mighty deep, even when it's shallow. Fear is a much-underrated virtue.
