TEST RESULTS 



The results of the Steady Speed Runs are given on pages 26 

 and 27. This data is divided into three sections, for the conditions 

 noted: 



(a) Aft Peak Tank Empty - Shallow Water 



(b) Aft Peak Tank Full - Shallow Water 



(c) Aft Peak Tank Full - Deep Water 



Ordinarily only the deep water condition would be studied, 

 preferably with the Aft Peak Tank full. In this instance however, 

 further information was desired on the influence of depth of water, 

 displacement, the presence of fluid in the Aft Peak Tank and rudder 

 control. The additional runs for conditions (a) and (b) would not be 

 required in future tests. 



The results of the Maneuvering Runs are given on page 28. 

 Since only two channels could be recorded simultaneously, the selec- 

 tions made were as noted under Test Procedure. If a multi -channel 

 system is used in the future, all channels could be then recorded 

 simultajieously. It is recommended however, that only the vertical 

 and athwartship measurements of the stern are important. 



The required plots of vibration amplitude versus RPM are 

 shown on Figures 10 through 13. 



The anchor drop-and-snub tests permitted the identification 

 of three vertical modes of flexural vibration of the hull at 1.5, 2.75 

 and 4. 93 cps . The main purposes of the anchor drop-and-snub tests 

 are to determine these frequencies and to provide a basis for esti- 

 mating damping characteristics of ships hulls . Since this latter aspect 

 of the program is more fundamental in nature and not directly assoc- 

 iated with the evaluation of the ship's vibration characteristics, no 

 further discussion on the subject is given in this report. On future 

 studies which may be carried out on other ships, it has been proposed 

 that the oscillograph records obtained during the anchor drop-and-snub 

 tests be included with the report. The study of hull damping character- 

 istics may then be undertaken as a separate program. 



47 



