with construction of the island watched their efforts reflected in the 

 model with gratifying interest. 



Scuba diving gear, also used by the engineer's field staff for in- 

 specting the underwater port of the work, proved useful. Although there 

 are drawbacks to the use of scuba gear, its outstanding advantage is that 

 it allows the engineer to see the object in question. Additional advan- 

 tages of scuba inspection are summarized as follows: 



(1) Equipment is relatively inexpensive. 



(2) For a diver with limited training and experience, scuba is 

 safer than conventional diving gear, although basic training is still 

 essential . 



(3) Equipment is easily portable, so that elaborate prepara- 

 tions for a dive are not necessary. 



(4) The diver has greater mobility and flexibility of operation. 

 Against these advantages the following disadvantages must be balanced: 



(1) There is no undeiTvater communication system equal to a 

 helmet diver's phone system. Some of the other drawbacks mentioned are a 

 direct result of this deficiency. 



(2) Unless the water is clear, orientation is more difficult to 

 maintain than when using conventional deep-sea gear. A compass is often 

 very helpful, but is useless if ferrous metal is in the vicinity. 



(3) Scuba divers should work in pairs for safety. 



II. EVALUATION OF DESIGN CHARACTERISTICS 



1. Wave Exposure 



a. Predicted Wave Exposure - Wave forecasts for the island site were 

 prepared in great detail, and covered estimated heights, periods, direction, 

 and frequency of occurrence. Basic data for wave forecasts were compiled 

 from available wave measurements by wave recorders and trained observers, 

 hindcasting from synoptic weather maps, and past records of severe storms. 

 Refraction studies were then used to adjust this information to the speci- 

 fic location of the island. The Channel Islands and the generally east- 

 west trend of the coastline west to Point Conception serve to protect the 

 island site from many, but by no means all, of the Pacific's winter storm 

 waves. That this partial protection confines the approach of large waves 

 to a narrow sector of almost unlimited fetch to the west had considerable 

 influence in determining the odd configuration of the island, as well as 

 its orientation. 



Wave studies also included an examination of lower wave heights from 

 all directions, which, though less damaging, still had an influence on the 



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