Figure 15. Deep Ocean Test Instrument Placement and Observation 

 System (DOTIPOS) used in in-situ vane shear and cone 

 penetrometer tests and in installing LOBSTERs. 



In-Situ Vane Shear Device 



The in-situ vane shear device 30 is capable of testing cohesive seat loor 

 sediments in water depths to 6,000 feet and to sediment depths of 10 feet. 

 This device is operated in conjunction with NCEL's DOTIPOS (Figure 15) 

 as discussed earlier. Four-bladed vanes of various sizes ranging from 2 x 4 to 

 4x8 inches have been designed, the size to be used depending on the expected 

 sediment strength range for a site. Sediments with shearing strengths up to 

 approximately 10 psi can be tested with this device. Both initial and remolded 

 sediment strengths can be assessed at selected sediment depth increments to 

 10 feet. A rotational speed of one revolution per hour is used for both tests. 

 Remolding is performed at a rate of 10 revolutions per minute. 



The test data are telemetered in analog form to the surface-support 

 vessel through a combined coaxial load-handling and electrical cable. With 

 the present system, these data are recorded on an oscillograph. A represen- 

 tation of the recorded field data is shown in Figure 1 6. The quantities 

 recorded include penetration resistance, vertical position of the vane, torque, 



29 



