SURF AROUND ISLANDS 



169 



the shores of islands, whether large or small. Thus, the waves are 

 likely to be focused, as it were, on the exposed side of an island that is 

 rounded in outline if it rises from water shoal enough to alter the di- 

 rection of advance of the waves to any considerable degree (fig. 53). 

 Consequently, just as at the tip of a headland (p. 163), a worse surf 



Figure 53. — Diagram to illustrate the refraction of waves around a circular is- 

 land that is surrounded by an evenly and gently sloping bottom. The depths 

 of the bottom contours are given in terms of the offshore wave length. 



may be expected there with a given wind than would develop on a 

 straight coast. But while the waves are often refracted right around 

 a small island of this shape, the heights of the breakers they produce 

 will decrease following around the shore, as their inshore ends are 

 delayed more and more by the effect of the bottom. Theoretically, the 

 inshore ends of waves, that were initially 20 to 100 times as long as 



