Peak Shear Stress (psi) 

 1.0 1.5 



3.0 



-c 3 



A 



□ 





A 



Test V-1 











□ 



Test V-2 





[ 



] 











a 



c 



i 

























D 



















□ 



Figure 17. Peak shear stress versus depth determined from in-situ vane 

 shear tests in a cohesive sediment off Pitas Point, California. 



The acoustic telemetry system is used to transmit the test data to the 

 support vessel; therefore, only a load-handling line is required from the vessel 

 to this device. The transmitted data, in analog form, are monitored by a 

 hydrophone receiver aboard the surface vessel, where signal conditioning and 

 recording equipment are also located. Figure 20 is a representation of an 

 oscillograph record which shows the quantities recorded for each test. Included 

 in this oscillograph record are the measurements for load, displacement, and 

 attitude of the device at corresponding times. An example of the data obtained 

 from these records is shown in Figure 21, which presents load— settlement 

 curves for various plate diameters for sediments in 6,000 feet of water off 

 San Miguel Island. 



The device is primarily a research tool being used to investigate the 

 short-term bearing pressure— settlement response of a variety of marine sedi- 

 ments, initial studies of which have been reported by Kretschmer. 33 The 

 relation between the laboratory-measured properties of the sediments and 



32 



