Unclassified 



Security Classification 



DOCUMENT CONTROL DATA - R&D 



ot title, body of abstract and indexing annotation must be entered when the overall report is classified) 



1. ORIGINATING ACTIVITY (Co 



David Taylor Model Basin 

 Washington D.C. 20007 



Unclassified 



3. REPORT TITLE 



PITCHING MOTIONS OF A MOORED SUBMERGED MINE IN WAVES 



4. DESCRIPTIVE NOTES (Type of reporl and inclusive dates) 



Final Report 



5. AUTHORfSJ (Last name, first name, initial) 



J. N. Newman; P. Plaia; E. E. Zarnick 



6 REPO RT DATE 



March 1966 



_ NO. OF PAGE 



29 



7b. NO, OF REFS 



1 



Sa. CONTRACT OR GRA1 



NOL WR 5-0044 



b. PROJEC T NO. 



REPORT NUMBERfSJ 

 2151 



10. AVAILABILITY/LIMITATION NOTICES 



Distribution of this document is unlimited. 



11. SUPPLEMENTARY NOTES 



12. SPONSORING MILITARY ACTIVITY 



U.S. Naval Ordnance Laboratory, 

 White Oak 



13. ABSTRACT 



This report describes a theoretical and experimental in- 

 vestigation of the pitching motions of a moored, submerged mine. 

 The theoretical predictions are based upon linearized-wave 

 theory as well as the assumptions that the body is slender and 

 axisymmetric and is ballasted to be at equilibrium in the 

 horizontal plane. The mooring cable is assumed to be mass less and 

 inelastic; the fluid is assumed to be inviscid. The theory results 

 in an equation of undamped motion. Parallel experimental results 

 were obtained on a 2-foot long model in wavelengths ranging from 

 15 to 55 feet, and these results confirm the theoretical predictions 

 except in the vicinity of resonance, where viscous damping is 

 important. Full-scale predictions are made for the root-mean- 

 square pitching motions in Sea States 4 through 7 for two 

 proposed mine configurations at various depths of submergence. The 

 predicted values are from 1 to degrees in Sea State 4, depending 

 on depth and mine configuration, increasing to greater than 25 

 degrees in Sea State 7. 



DD /.?re. 1473 



Unclassified 



Security Classification 



