INSTRUMENTATION AND RECORDING PROCEDURES 



A. Instrumentation 



Wave, ship, and fluid motion observations discussed in this report were made from 

 aboard the REDFIN. Instrumentation utilized and variables measured are included in 

 the listing that follows. Locations of these instruments on the submarine are shown in 

 Figure 1 . 



Pitch and Roll Angle David Taylor Model Basin stable 



platform and potentiometer 



Relative Flow Velocity Litton Electromagnetic Flow Meter 



In Situ Pressure Fluctuations Wiancko Pressure Measuring System 



(U.S. Navy Mine Defense Laboratory) 



Ship's Speed Ship's Electromagnetic Log 



Ship's Course Ship's Gyrocompass 



Depth (pressure) Vibrotron and Bourns potentiometer 



in the pressure gauge Sine 



Surface Wave Profile Westinghouse Sonic Surface Scanner 



Figure 2 illustrates a portion of a typical recording taken aboard the REDFIN. 

 Most data were recorded on both magnetic and paper tape. Surface wave and in situ 

 pressure fluctuation data, however, were recorded on magnetic tape only. A com- 

 plete description of the instrumentation and measurement and recording procedures is 

 given in the Hydrographic Office Technical Report No. 91 (Reference 10). 



Nearly all pitch angle recordings, heave acceleration, and sway acceleration 

 were practically fiat and will not be discussed further in this report. Thus, the only 

 submarine motion of interest is roll angle. Some cross-flow data with very low 

 amplitudes were deleted. 



Although attempts were made to provide analog recordings of in situ pressure 

 fluctuations measured by the Wiancko pressure gauge, most of the collected data were 

 deleted because the amplitude of the recording's envelope frequently exceeded the 

 dynamic range of the pressure gauge. When this occurred, the relief valve in the gauge 

 would open, resulting in intermittent jumps in the continuous recordings. Attempts to 

 filter these pressure data before spectral analysis were not too successful, and most of 

 the spectra of the Wiancko recordings were not considered valid. 



