Edge of the Sea 

 C. A. M.King 



The destructive forces of waves year by 

 year eat away many coasts. Building 

 brealiwaters is one way to diminish 

 the destructive forces of the wai/es, but, 

 liS^e the coast itseif, breal^waters are in 

 time worn away by the endiess train of waves. 



If we go down to the edge of the sea from the land, the rocks or 

 beach at the shore line first command our attention. But beyond 

 the shore are the waves of the sea, waves born of the wind and 

 which travel effortlessly for hundreds and thousands of miles until 

 they break upon the beach and help shape the coast. To understand 

 the changing nature of the edge of the sea, we must first understand 

 the nature of waves, for the two are inexorably linked. 



From a small boat out in the open ocean the sea appears to be 

 in a state of chaos, especially if there is a strong wind. Waves of 

 different lengths, different heights, and traveling at different speeds 

 and in different directions interlace and engulf each other. Away 

 from the land, where waves are being formed by wind, they are 

 known as sea. Here they build in height (distance from trough to 

 crest) and in length (distance from crest to crest). They build as the 

 wind strength rises, as its duration lengthens, and as the distance 

 across which it blows increases - called its fetch. Although we can 

 make generalizations about waves, we still do not know exaalj 

 how they grow, exactly how the energy that forms them is trans- 

 ferred from the air to the water. Waves that are growing are usually 

 fairly short in length compared with their height, and we describe 

 them as being steep. Scientists working at England's National 

 Institute of Oceanography, located in Surrey, have invented a ship- 



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