TABLE OF CONTENTS 



Page 



SUMMARY 1 



I. THE MEASUREMENT OF SOUND SPEED IN THE OCEAN: 

 REQUIREMENTS FOR THE NAVY 



A. Introduction 2 



B. Requirements for Tactical Situations & Prediction 5 



C. Requirements for Oceanographic Survey 12 



D. Problem Areas 



1. The Velocity of Sound in Ocean Patches 13 



2. Interfaces 15 



3. The Velocity in the Sea Bottom 16 



4. Velocity Dispersion in Sea Water and the 

 Pressure Coefficient of Velocity 17 



II. REVIEW OF INDIRECT METHODS OF VELOCITY MEASUREMENT 



A. Introduction 18 



B. Thermistor Chain 18 



C. Reversing Thermometer and Bathythermograph 20 



D. Expendable Bathythermograph 20 



E. S.T.D. Instrument 24 



III. REVIEW OF VELOCIMETERS 



A. Introduction 26 



B. Tabular Listing of Velocimeters 28 



C. Discussion of Direct Methods 35 



IV. COMPARISON OF METHODS AND RECOMMENDATIONS 



A. Comparison of Direct and Indirect Methods 40 



B. Problems and Recommendations 



1. Depth Accuracy 43 



2. Velocity Accuracy 43 



3. Expendable Velocimeters 45 



4. Possibilities of Hybrid Systems for Maximum 

 Cost-Effectiveness and Recommendations 46 



V. CONCLUSIONS 51 



REFERENCES 53 



APPENDIX A - Ray-plots for Various Velocity 



Profiles A-l 



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