In February 1933 the U.S.S. Ramapo, while proceeding from Manila to San Diego, encountered seven days of stormy weather. The storm was part of a weather disturbance that extended all the way from Kamchatka to New York and permitted the winds an unbroken fetch of thousands of miles. During the height of the storm the Ramapo maintained a course running down the wind and with the sea. On 6 February the gale reached its fiercest intensity. Winds of 68 knots came in gusts and squalls, and the seas reached mountainous height. While standing watch on the bridge during the early hours of that day, one of the officers of the Ramapo saw, in the moonlight, a great sea rising astern to a level above an iron strap on the crow’s nest of the mainmast. The Ramapo was on even keel and her stern was in the trough of the sea. These circumstances made possible an exact line of sight from the bridge to the crest of the wave, and simple mathematical calculations based on the dimensions of the ship gave the height of the wave. It was 112 feet.
Waves have taken their toll of shipping and of human life on the open sea, but it is around the shorelines of the world that they are most destructive. Whatever the height of storm waves at sea, there is abundant evidence, as some of the case histories that follow will show, that breaking surf and the upward-leaping water masses from thundering breakers may engulf lighthouses, shatter buildings, and hurl stones through lighthouse windows anywhere from 100 to 300 feet above the sea. Before the power of such surf, piers and breakwaters and other shore installations are fragile as a child’s toys.
Almost every coast of the world is visited periodically by violent storm surf, but there are some that have never known the sea in its milder moods. ‘There is not in the world a coast more terrible than this!’ exclaimed Lord Bryce of Tierra del Fuego, where the breakers roar in upon the coast with a voice that, according to report, can be heard 20 miles inland on a still night. ‘The sight of such a coast,’ Darwin had written in his diary, ‘is enough to make a landsman dream for a week about death, peril, and shipwreck.’
Others claim that the Pacific coast of the United States from northern California to the Straits of Juan de Fuca has a surf as heavy as any in the world. But it seems unlikely that any coast is visited more wrathfully by the sea’s waves than the Shetlands and the Orkneys, in the path of the cyclonic storms that pass eastward between Iceland and the British Isles. All the feeling and the fury of such a storm, couched almost in Conradian prose, are contained in the usually prosaic British Islands Pilot:
In the terrific gales which usually occur four or five times in every year all distinction between air and water is lost, the nearest objects are obscured by spray, and everything seems enveloped in a thick smoke; upon the open coast the sea rises at once, and striking upon the rocky shores rises in foam for several hundred feet and spreads over the whole country.
The sea, however, is not so heavy in the violent gales of short continuance as when an ordinary gale has been blowing for many days; the whole force of the Atlantic is then beating against the shores of the Orkneys, rocks of many tons in weight are lifted from their beds, and the roar of the surge may be heard for twenty miles; the breakers rise to the height of 60 feet, and the broken sea on the North Shoal, which lies 12 miles northwestward of Costa Head, is visible at Skail and Birsay.
The first man who ever measured the force of an ocean wave was Thomas Stevenson, father of Robert Louis. Stevenson developed the instrument known as a wave dynamometer and with it studied the waves that battered the coast of his native Scotland. He found that in winter gales the force of a wave might be as great as 6000 pounds to the square foot. Perhaps it was waves of this strength that destroyed the breakwater at Wick on the coast of Scotland in a December storm in 1872. The seaward end of the Wick breakwater consisted of a block of concrete weighing more than 800 tons, bound solidly with iron rods to underlying blocks of stone. During the height of this winter gale the resident engineer watched the onslaught of the waves from a point on the cliff above the breakwater. Before his incredulous eyes, the block of concrete was lifted up and swept shoreward. After the storm had subsided divers investigated the wreckage. They found that not only the concrete monolith but the stones it was attached to had been carried away. The waves had torn loose, lifted, and bodily moved a mass weighing not less than 1350 tons, or 2,700,000 pounds. Five years later it became clear that this feat had been a mere dress rehearsal, for the new pier, weighing about 2600 tons, was then carried away in another storm.
A list of the perverse and freakish doings of the sea can easily be compiled from the records of the keepers of lights on lonely ledges at sea, or on rocky headlands exposed to the full strength of storm surf. At Unst, the most northern of the Shetland Islands, a door in the lighthouse was broken open 195 feet above the sea. At the Bishop Rock Light, on the English Channel, a bell was torn away from its attachment 100 feet above high water during a winter gale. About the Bell Rock Light on the coast of Scotland one November day a heavy ground swell was running, although there was no wind. Suddenly one of the swells rose about the tower, mounted to the gilded ball atop the lantern, 117 feet above the rock, and tore away a ladder that was attached to the tower 86 feet above the water. There have been happenings that, to some minds, are tinged with the supernatural, like that at the Eddystone Light in 1840. The entrance door of the tower had been made fast by strong bolts, as usual. During a night of heavy seas the door was broken open from within, and all its iron bolts and hinges were torn loose. Engineers say that such a thing happens as a result of pneumatic action—the sudden back draught created by the recession of a heavy wave combined with an abrupt release of pressure on the outside of the door.
On the Atlantic coast of the United States, the 97-foot tower on Minot’s Ledge in Massachusetts is often completely enveloped by masses of water from breaking surf, and an earlier light on this ledge was swept away in 1851. Then there is the often quoted story of the December storm at Trinidad Head Light on the coast of northern California. As the keeper watched the storm from his lantern 196 feet above high water, he could see the near-by Pilot Rock engulfed again and again by waves that swept over its hundred-foot crest. Then a wave, larger than the rest, struck the cliffs at the base of the light. It seemed to rise in a solid wall of water to the level of the lantern, and it hurled its spray completely over the tower. The shock of the blow stopped the revolving of the light.