at the site is 85 feet; sediments are calcareous sand. No settlement has been 

 noted. The cameras, supported on flat pads, were placed in 50 to 100 feet 

 of water. Sediments at the site were a dense granular material. No settle- 

 ments were observed. 



Rectangular Block 



Weight in air: 3,974 lb 



Weight in water: 2,219 lb 



Bearing pressure in water: 

 1.14 psi 



Square Block 



Weight in air: 3,970 lb 

 Weight in water: 2,214 lb 

 Bearing pressure in water: 

 1.71 psi 



Circular Block 



Weight in air: 3,700 lb 



Weight in water: 2,076 lb 



Bearing pressure in water: 

 1 .15 psi 



Figure 23. Dimensions and weights of concrete blocks used in St. Andrew's 

 Bay model studies. (After Keller, 1964.) 



Other Structures. The Applied Physics Laboratory (APL), a division 

 of the University of Washington, maintains FORAC stations at various localities 

 ( Linger, 1 969) . The devices, placed in 1 00 to 2,600 feet of water, consist of 

 tripods with transducers. No indication of unsatisfactory performance has 

 been reported. 



38 



