(b) Wave Conditions. Both sea and swell conditions, fairly constant throughout 

 year, originating in northwest quadrant with about 50 percent from northwest, in the low to 

 medium range. 



(c) Currents. Variable in direction but mostly north-northwest and south- 

 southeast and averaging 1/3 to 2/3 knots. 



(d) Winds. PrevaiUng wind direction during most of year is northwest, with low 

 average velocity. Occasional east and northeast winds through coastal mountains with speeds 

 possibly exceeding 50 miles per hour. Gales infrequent, occurring in only 1 percent 

 observations in December and January, with no predominant direction. 



(e) Storm Surge and Tides. Maximum astronomical tide range about 10 feet; 

 storm surge not known but reportedly in range of additional 10 feet. 



(f) Littoral Transport. Reportedly negligible. 



(g) Water Depth at Structure. 42 feet MLW. 



(h) Foundation Conditions. Sandy ocean bottom. 



(5) Structural Features (Figs. 18 and 19). 



(a) Dimensions of Basic Structure. 75-foot-diameter steel sheet-pile cell with 

 58.5- X 72.5-foot pile-supported wharf adjoining. 



(b) Unusual Features. Earliest of California's offshore driUing islands designed to 

 satisfy State Lands Commission resolution requiring wells in area to be drilled from filled 

 islands offshore. 



(6) Design Data. 



(a) Design Conditions: 



Depth of structure, 42 feet MLLW 

 Astronomical tide, 5.4 feet 

 Storm surge (not available) 



(b) Model Study. None. 



(c) Instrumentation. None. 



(7) Structural Performance. 



(a) Performance. Satisfactory with no measurable movement. In 1972, during a 

 general overhaul program, test sections cut from sheeting indicated negligible decrease in 

 thickness due to corrosion, and core borings through concrete top surface of cell indicated 

 less than 1 inch average settlement of filled interior. 



(b) Maintenance. No maintenance other than repair of timber fendering. In 

 1972, a general overhaul consisted primarily of sandblasting and painting of all exposed steel 

 sheet-pile surfaces above water. All wharf timber piles, gunited before driving, were checked 

 for soundness and repaired with concrete as necessary, mostly at top just below pile cap. 



(8) Effect of Structure on Environment. 



(a) Physical. No known physical effect on hydrography in the area. 



(b) Biota. Marine growth on the underwater, unpainted areas attracts fish 

 which in turn attract sport fishermen (Fig. 19). 



40 



