CG-47

                          CG 47 CLASS ADVISORY NO. 00-94                        

                                                                                

 Subj:   DDG51, CG47, DD963, DDG993, FFG7 CLASS ADVISORY, MK 32 TORPEDO         

 TUBES                                                                          

                                                                                

 REF:  A.  USS BARRY (DDG52) ACCEPTANCE TRAIL CARD 1G0125AS01/930222            

       B.  NAVSEAINST 8515.1C TORPEDO MK 46 FIRING REPORTING SYSTEM             

                                                                                

 1.  Ref (a) reported insufficient air pressure in MK 32 MOD 15 Surface         

 Vessel Torpedo Tube (SVTT) breech mechanism which resulted in a barrel         

 not-ready indication inhibiting launch of over-the-side torpedoes.             

 Investigation disclosed that this problem was the result of a new              

 operating pressure switch required for Torpedo MK 50 capability.               

                                                                                

 2.  SVTT MK 32 MOD 15 (DDG 51 Class) are baselined with Torpedo MK 50          

 capability.  All other ships designated for Torpedo MK 50 capability           

 have or will receive ORDALT 15713.  ORDALT 15713 replaces the present          

 SVTT MK 32 Operating Pressure Switch (1200-1350 PSI) with a new Pressure       

 Switch (1300-1450 PSI) because of the higher minimum pressure required         

 to launch the heavier Torpedo MK 50.                                           

                                                                                

 3.  Request TYCOMs advise subj Class ships to increase maximum air flask       

 pressure from 1500 to 1600 PSI after installation of ORDALT 15713.  This       

 100 PSI increase will resolve the barrel no-ready condition and provide        

 adequate pressure to successfully launch both MK 46 and MK 50 Torpedoes.       

                                                                                

 4.  To monitor exercise Torpedo MK 46 launches and ensure increased            

 flask pressure (1600 PSI) does not cause increased incidents of                

 broaching due to reduce water entry angle.  Request firing ships provide       

 their firing data to NAVUNSEAWARCENDIV Newport (Code 8332) in addition         

 to distribution required by ref (b).                                           

                                                                                

 5.  Pen and ink changes to technical manuals and OPS material is               

 authorized to indicate an increase of flask charge pressure to 1600 PSI        

 for both weapons.                                                              

                                                                                

 6.  This advisory will be canceled within one year.                            

                                                                                

 7.  NAVSEA POC is:  Mr. Ron Carmichael (SEA 91W432) DSN:  332-6436.            

                                                                                

                                                                 07 FEB 94      

                                                           COMNAVSEASYSCOM