APPENDIX D 

 CALCULATIONS 



Section 1 

 Calculations By Naval Ship Engineering Center 



INTRODUCTION 



At the request of NAVSHIPS OOC, NAVSEC conducted studies to evaluate various as- 

 pects of the ALVIN Salvage Plan. The analysis and results contained herein were originally 

 submitted to NAVSHIPS OOC as Enclosures (1) and (2) of NAVSEC 6162 Memo Serial 229, 

 15 August, 1969. Acknowledgement is made to H. W. Stoll of Deck Systems Branch, NAV- 

 SEC, for his assistance in the preparation and compilation of these studies for inclusion in 

 this ALVIN salvage report. 



DISCUSSION 



Plans for the salvage of the submersible ALVIN called for the use of a 4V2-inch-circum- 

 ference Plimoor nylon rope to lift ALVIN from nearly 5,000 feet of water. The lift was to 

 be made using USNS MIZAR. Concern was expressed over the possibility that dynamic res- 

 onance may be generated during the lift by ship motion exciting the spring-mass system formed 

 by ALVIN and the nylon rope. 



NAVSEC analyzed this spring-mass system with the intent of establishing the extent of 

 the resonant problem and the hope of suggesting possible preventive action. Accordingly, 

 the spring-mass system was analyzed for the following cases: 



Case I 



In a meeting of interested parties held on Wednesday, 30 July 1969, it was agreed that 

 the lift line would be deployed through the center well of MIZAR in order to prevent roll 

 and pitch motion from exciting the spring-mass system. ALVIN's mass including apparent 



9 4- 



mass effects was assumed to be 1,300 Ib-sec/ft* and her static weight in water was assumed 



59 



