Pneumat i c-hydraul i c pump on calibration c o lumn in 

 shed supplies water to vessel at pressure 10 times 

 that of supply air. 



ACOUSTICAL DESIGN 



Maximum operating pressure was set at 800 psig 

 by the demand for calibration at the depth it represents. 

 Acoustic attenuation is acceptable with the wall thickness 

 required by this pressure. 



The steel cap was considered to be located far enough 

 from the transducer under test to be of no acoustical con- 

 sequence. If it had become a source of significant reflec- 

 tions, it would have been coated with Goodrich absorbent 

 rubber SOAB, 



