Table 1 is a summary of test conditions for Runs 3, 4, 5, and 6 of Cruise II . The 

 firsf recording began with Run 3. Wave conditions were generally mild except for the 

 first four recordings of Run 3. On four of the runs (Runs 4-1, 5-1, 5-4, and 6-3), large 

 variations in depth occurred because of temporary loss of buoyancy control . However, 

 such large depth variations were of very short duration, and the submarine generally 

 was able to return to its original hovering position in about 7 minutes. All runs where 

 this occurred were continued for 30 minutes after depth was regained, and only this 

 portion of the record was analyzed. 



Submarine motions and relative flow velocity of water across the submarine's deck 

 occur as a result of surface wave motion. Since motion characteristics of submarines 

 will be required under various sea states, It is essential that some estimate of the surface 

 wave spectrum be available. Such spectra can be obtained by hindcasting from the 

 synoptic sea-level surface weather maps by methods described in H. O. Pub No. 603 

 (Reference 9). However, the exact functional form of the Pierson-Neumann spectrum 

 and its dependence on such parameters as wind speed, wind duration, and fetch length 

 are presently being improved. Hence, It is essential to obtain a series of surface wave 

 spectra over the open ocean so that differences between measured and predicted spectra 

 can be reconciled. 



Although the Sonic Surface Scanner method is still in the experimental stage, it is 

 a promising method of obtaining series of surface wave records in the open ocean. Sub- 

 ject to corrections for the motion of the submarine, it should be possible to obtain reli- 

 able spectral estimates of surface wave heights from such records. 



B . Surface Wave Height Spectra - 



Surface wave height spectra for Runs 4 and 6 are shown in Figures 10 and 11,. 

 respectively. The sonic scanner was inoperative during Runs 3 and 5. Figures 10 and 

 1 1 indicate that wave conditions were stationary during each of these series of runs. 

 No corrections have been applied to these surface wave spectra, since the amount of 

 wave energy associated with high period waves Is rather low. Table 2 presents the 

 90-percent confidence intervals for these spectra. 



Each of the submarine and fluid motion spectra shown in the composite graphs 

 (Figs. 12 to 21) was obtained in the same form as depicted in Figure 8. For ease of 

 comparison and identification, however, a smooth curve was reconstructed from each 

 analog spectrum. 



C. Roll Angle Spectra 



Figures 12 through 15 present analog energy spectra of roll angles for Runs 3 to 6. 

 Each figure contains 4 spectra corresponding to a different relative heading. Each roll 



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