112 



BREAKERS AND SURF 



over a gently sloping beach from a rocky promontory. An old swell 

 was heaving in, the individual members of which were so low that 

 they were not recognizable offshore but which grew to heights of li/ 2 

 to 3 feet at the breaker line. Those that rose the highest were of the 

 plunging type, but the smaller ones were of the spilling type, and in 

 many cases one part of a single wave crest developed as the one type, 



■f- in. ■ 



0i& M. 



rK.UKK 23.— Oblique view of a breaker of the plunging type on the coast of New 

 Jersey. (Woods Hole Oceanngrnphic Institution photograph.) 



another part as the other; or a "spilling" breaker might either follow 

 or precede a "plunging'' one. 



Long, gentle swells— initial steepness (H:L) less than 0.005— com- 

 monly produce breakers of the plunging type, especially when the 

 wind is blowing offshore, while waves that are less than 100 tunes as 

 long, offshore, as they are high, often produce breakers of the spilling 

 type, especially when the wind is blowing onshore. But individual 



