DOTIPOS was then returned to the water surface where SCUBA divers either 

 cleaned the soil that adhered to the vane tool or changed the size of the 

 vane tool. DOTIPOS was returned to the seafloor and repositioned for 

 additional testing according to the above appropriate procedure before 

 being returned to the ship's deck. 



EVALUATION OF DEVICE PERFORMANCE 



DOTIPOS, with the vane shear and cone penetrometer subsystem, was 

 found to operate quite satisfactorily at the 100- and 600-foot deep 

 test sites. 



Several sets of vane shear tests and cone penetrometer tests may 

 be performed during an eight-hour work day. It takes approximately 

 20 minutes to transport DOTIPOS from the deck to the seafloor and the 

 same time to return it to the deck at the 600-foot test site. With 

 DOTIPOS on the seafloor, a set of vane shear tests at one-foot 

 intervals may be performed on an average of about one each 90 minutes, 

 and a cone penetrometer test may be performed in about 25 minutes. 



The tests were performed from a U. S. Navy ARS and a U. S. Navy 

 LST. Both ships have ample deck space to hold the DOTIPOS structure 

 and winch system. Many ships, such as the AGOR class, have neither the 

 deck space to set up the three units of the winch system nor a crane 

 capable of lifting the DOTIPOS platform. The load handling of the 

 DOTIPOS platform from the ARS and LST was no problem when the wave 

 height was less than 5 feet. 



Problems which occurred during the sea trials were of a minor 

 nature. The more notable problems include (1) bent vane shear tools, 



(2) shear pin failure in the television camera pan and tilt unit, and 



(3) hydraulic seal failure to electrical components. All of the 

 problems were easily recognized and corrected. With these various 

 modifications, the quality and reliability of DOTIPOS and the vane 

 shear and cone penetrometer subsystem was significantly enhanced. 



TEST RESULTS 



Results from the tests performed in the Laboratory and in situ on 

 Site 1 (Pitas Point 100-foot test site) and Site 2 (SEACON 600-foot 

 test site) sediments are presented in the following paragraphs. All 

 vane shear data were reduced according to Equation 1 (Introduction) . 



Site 1 



Soil Properties . Several cores were taken at Site 1. A comparison 

 of previously obtained core data (Kretschmer, 1967) with data retrieved 

 from core samples obtained in conjunction with the vane shear, cone 

 penetrometer evaluation indicates that Site 1 sediment has good areal 

 uniformity. Therefore, only typical laboratory results from one core 

 will be presented. A Ewing-type gravity corer was used. 



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