46 WAVES 



forced forward and falls into the trough ahead. A very strong wind 

 may even blow the water bodily ahead from the crests in sheets of foam 

 or spray, so that waves may not reach their maximum heights until 

 the wind has slackened somewhat (p. 19). In small bodies of water, 

 indeed, severe squalls or winds of hurricane force may lift sheets of 

 spray bodily from the surface in this way, even when the waves are 

 very small, as we have seen ourselves. And the violent squalls that are 

 a usual feature of full gales, when the average velocity of the wind 

 may be 50 to 00 miles an hour, or even higher, often raise the breaking 

 crests so high above the general wave level that if these masses of 

 water chance to fall on deck, lifeboats are often stove in, stanchions 

 carried away, etc. 



In short, the old rule still holds and always will, that it is the waves 

 of a storm, not its winds, that the mariner has to fear; also that a 

 high and heavily breaking sea is a dangerous one, whenever and 

 wherever it is encountered. 



Lest anyone should think that danger of serious damage by waves 

 to well-found steamers is a thing of the past, we cite the cases of the 

 U. S. heavy cruiser Pittsburgh, 100 feet of the bow of which was torn 

 away bodily by an enormous sea during a typhoon in the western 

 Pacific, June 5, 1945, and of three United States destroyers that were 

 lost during a similar cyclonic storm between the Philippines and the 

 Marianas on the eighteenth of the previous December. 



The foregoing discussion of the dimensions and profiles of waves 

 has been oversimplified intentionally, by the tacit assumption that 

 waves are more or less regular in shape and that they are distinct, one 

 from the next; also, that their crests extend sidewise for indefinite 

 distances. But this is never the case in reality, for the topography of 

 the surface of the sea is always extremely complex and irregular. 

 Whenever the wind is high, waves of all sizes, from the very smallest 

 up to the highest that have yet developed are intermingled, with 

 neighboring waves differing in shape from comparatively low and 

 long to so short and sharp that they are breaking, or about to do so. 

 Secondary ridges, peaks, and valleys are also to be seen, running on top 

 of what may be called the primary series (figs. 13 and 14), which, in 

 turn, may or may not run in the direction of the wind. Also, it is 

 only when the "seas" have been transformed into "swells" as described 

 below (p. 63) that the individual crests extend far widewise. In 

 stormy weather, on the contrary, their lateral breadth may not be more 

 than three to five times as far as it is from one crest to the next, and 

 sometimes no farther than it is from crest to crest, with their ends 

 merging into the valleys in a wholly irregular pattern. The result is 

 that any profile, transverse to the general trend of the waves, is always 

 a very irregular one, so long as the wind is blowing strongly. 



