embedded the acoustic projector is in seawater, not soil. In general, 

 it seems that reasonable estimates of the sound velocity can be made to 

 minimize errors from this factor. 



CONCLUSIONS 



1 . Using a Doppler instrumentation system to monitor the kinematics of 

 a free-falling penetrometer is workable. 



2. Accurate determinations of penetrometer penetration can be made 

 using the Doppler instrumentation system. 



3. The Doppler instrumentation system is capable of showing change in 

 resistance to penetration which is indicative of soil strength changes. 



4. The expendable Doppler penetrometer reaches a terminal velocity of 

 about 80 feet per second which, based on penetration theory, is sufficient 

 to attain about 30 feet of penetration in a typical deep ocean clay (red 

 or pelagic clay) . 



5. Factors that affect the Doppler frequency shift will not cause large 

 errors in the data and can be reduced to an error of a few percent with 

 proper data interpretation. 



FUTURE PLANS 



Twenty Expendable Doppler Penetrometers will be fabricated on 

 contract.* These units will be tested at a variety of locations and in 

 a variety of seafloor soils. They will be tested in soft clay (1,200- 

 foot site and perhaps 5, 600- foot site), in firm clay (Seacon I site), 

 and in a sandy- silt (Seacon II site) which are all near Port Hueneme. 

 Testing will also be performed in both a deep ocean red clay and calcareous 

 ooze. These deep ocean tests will be conducted in conjunction with 

 other projects that plan to visit sites for gathering soil data or to 

 test the CEL 20K deep water anchor. The test program outlined will 

 provide comprehensive information on the performance of the Expendable 

 Doppler Penetrometer. The results of the tests will be analyzed and 

 reported. 



Prototypes of these units have been delivered. Tests have 

 shown that they meet all specifications. 



