C. CONCLUSIONS 



No satisfactory commercially available oceanographic depth gauge 

 is available today other than the unprotected reversing thermometer. 



The problem of developing a telemetering depth gauge that uses 

 commerically available pressure sensors is considered to be within 

 the capability of this Office. 



D. RECOMMENDATIONS 



Since September 1959 a vibrating wire depth gauge has been used 

 as part of an oceanographic data collection system installed aboard 

 a submarine and has been evaluated as being reliable and accurate. 

 However, the operational depth of a submarine is fairly limited in 

 terms of deep ocean applications, and it is recommended that this 

 Office continue its development and testing of the vibrating wire depth 

 gauge. 



It is also recommended that the Hydrographic Office conduct 

 further calibration tests on the Bourdon gauges to determine their 

 expected accuracies; and if the accuracies are acceptable, this Office 

 then should develop inexpensive Bourdon actuated depth gauges for 

 use to 400, 2,500, and 10,000 feet, respectively. If these tests continue 

 to indicate large errors in these gauges, this Office should endeavor 

 to reconcile these results with results of other users of such gauges. 



It is further recommended that the Hydrographic Office investigate 

 the feasibility of employing a strain gauge as the sensor is a depth 

 meter. 



Finally, it is recommended that the Hydrographic Office evaluate 

 the sonar pinger system. 



E. SELECTED REFERENCES 



V-l. BEHAR, M. F., ed. Handbook of measurement and control. 

 Instrumentation and Automation, vol. 27, no. 12, Pt. 2, Decem- 

 ber 1954. 216 p. 1954. 



V-2. BODEN, B. P., and others. A depth telerecording unit for 

 marine biology, Journal of Marine Research, vol. 14, no. 2, 

 p. 205-209, 1955. 



V-7 



