CONFIDENTIAL REPORT 2G-21
S24
     
 
FORMER GERMAN SUBMARINE TYPE XXI
 
 
 
 
SHIP CONTROL
 
     
 
SUMMARY
  
     
          Ship control equipment is similar in type and location to that provided on earlier types, although the pressure-proof components are slightly modified to take increased pressure, and the depth gauges have a range of 50 meters and 400 meters.  
          The only change of consequence is the elimination of the drum hoist and hydraulic motor for periscope hoisting, and the installation, in lieu thereof, of a hydraulic ram with cables rigged to the fixed and moving parts of the ram in such a way as to give a reverse purchase.  This multiple purchase permits the stroke of the hydraulic piston to be limited to the vertical space available in the conning tower, while taking up the entire length of cable necessary to hoist the periscope.  The mechanism is rugged and silent and has the further advantage of not projecting beyond the hull of the vessel, and of not exposing the hydraulic system to salt water contamination.  
     
     
     
     
 
March, 1946
 
 
 
 
PORTSMOUTH NAVAL SHIPYARD, PORTSMOUTH, N. H.