CONFIDENTIAL REPORT 2G-21
S23
     
 
FORMER GERMAN SUBMARINE TYPE XXI
 
 
 
 
AUXILIARY MACHINERY GENERAL
 
 
SOUND INSULATION & SHOCK MOUNTING
 
     
 
SUMMARY
 
     
          The detailed information with regard to the design and application of auxiliary machinery is delineated in the applicable "S" group reports.  In addition reference should be made to Report 2G-9C-S23 for detail information with regard to sound isolation and shock mounting as the practices observed are very similar.  
          Differences exist as follows - lighting fixtures, gauge boards, fuze boxes, etc. which in other type vessels has been mounted on rubber mounts are now found to be mounted on steel spring mounts which are described and illustrated in Nav Tech Report 251-45.  
          Considerable effort has been expended in designing auxiliary machinery foundations to load the bonded rubber mounts in compression only.  
          The creeping speed motors are mounted on bonded rubber mounts and are provided with V-belt drive between motor and shaft.  As a further measure to minimize the sound output the field poles are designed with a herringbone skew.  This feature is described in detail in Nav Tech Report 303-45.  
          Results of a sound test made by Subbase N.L. on the auxiliary machinery installed in U-2513 are contained in report form as Enclosures (A), (B) and (C) to Commanding Officer Subbase N.L. ltr. NB7/S68E Serial 052 of 12 April 1946 to the Chief of the Bureau of Ships.  
     
 
July, 1946
 
 
 
 
PORTSMOUTH NAVAL SHIPYARD, PORTSMOUTH, N. H.
 
     
     
     
 
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