CG-47 CLASS ADVISORY NO. 03-91 MK 36 DECOY LAUNCHING SYSTEM (DLS) LEAKS
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COMNAVSEASYSCOM WASHINGTON DC MSG 121829Z FEB 91 REF: A. Technical Manual, NAVSEA SW393-A1-MMM-010/MK 36 DLS launching system, Nov 79 B. MIP 4741/001; MRC A0 GDKT N (M-1), Launcher inspection, Oct 90 C. MIP 4741/001; MRC A0 GDKW N (S-1R), Clean launch tube components, Oct 90 1. The purpose of this class advisory is to advise all CG 47 class ships of possible leakage in the MK 36 DLS and provide interim corrective action. 2. BACKGROUND. Experience during recent new construction ship sea trials revealed water leakage into the MK 36 DLS launcher terminal box, (Ref A, FIG 5-2, index nr 49 (P/N 3193558)). Investigation showed that the intrusion path is through the tube support gasket/foundation interface, then under the foundation and through cable ports in the terminal box. The causes are undersized gaskets and tube support manufacturing deficiencies. If the problem remains uncorrected, corrosion and grounding in the terminal box may occur. NOSL, as ISEA, is developing a kit to replace the existing gasket with one of the correct size. 3. ACTION. CG 47 class ships should conduct Ref B PMS inspection of launcher terminal box to assure that terminal box is clean, dry and free of corrosion. If water accumulation is evident take the following action: A. Remove water and/or corrosion B. Replace junction box cover and gasket C. Using Ref C, remove 45 degree supports from the base per para 1A7. Seal the edge of the support with a bead of RTV 3140, MIL-A-46146 or MIL-1A-46106, between gasket and support. Reinstall suport per para 1D 12-19. 4. For COMNAVSURFLANT/COMNAVSURFPAC - Recommend CG 47 class ships be tasked to carry out the provisions of para 3 above and to report any indications of leakage to the ISEA (NOSL), info orig. 5. For NOSL - advise orig and TYCOMS of availability and procurement procedures for new gasket kits. 6. This advisory has no impact on CSOSS, EOSS or PMS. It will be cancelled when the new gasket kits are installed on those ships having leakage. 7. Orig POC is LCDR HAMMERER, PMS400B30S, AV 332-7090 or Comm (703) 602-7090. ISEA POC is Mr. D. Whittle, Code 9011, AV 989-5725 or Comm (502) 364-5725. 8. Released by RADM J. T. HOOD. CG-47 CLASS ADVISORY (UNNUMBERED) CG 47 Class and DDG 51 Class Ward Leonard Motor Controller Heaters and N154 Overload Relays 1. The Ward Leonard (W/L) size 5 motor controller heaters specified in the heater tables and installed in CG 47 class and DDG 51 Class are one size too small for the full load motor currents. The heaters installed essentially operate at approximately 100 percent of their heater rating which is a tripping condition (causing nuisance tripping or susceptibility to tripping during shock). W/L has agreed to supply kits containing correct size heaters, new tech manual inserts with corrected heater table data, new tech manual inserts with corrected heater table data, new laminated instruction sheets for each controller, and installation instructions. A. W/L will provide all kits for delivered ships to NAVSSES code 113 for further installation on CG 47 class ships. B. Installation of heaters for INGALLS and BATH In-yard CG 47 and DDG 51 class ships will be accomplished by W/L reps working with both construction yards. 2. It has been previously discovered that the hex nut on the W/L N154 overload relay was loosening and causing the overload relay to trip prematurely. W/L began to use Loctite, an Anerobic Adhesive, on all new relays. Also, W/L field technicians gave out special torque wrenches to the ship's electrical tecnicians with specific instructions on their use for all previously delivered relays for which the hex nut had become loose. 3. Existing records indicate that CG 51 and CG 56 through CG 59 received W/L wrenches. Further Information indicates that additional wrenches were fabricated which did not meet torque requirements and could damage relays if used improperly. Based on examinations of suspect relays returned to W/L laboratory, approximately 30 percent of relays returned from ships have been destroyed by inappropriate torquing on the hex nuts. Most of the relays had loctite applied and therefore, there was no reason to use the wrenches. 4. Relays which have been improperly torqued may exhibit any one of the following characteristics: A. Nuisance tripping (Motors do not stay on-line). B Unable to reset (Clutch spring broken) Mmotors cannot be started). C. May not trip at low over currents (Motors continue to run under overcurrent conditions). D. May not trip at all (motors have no overcurrent protection). 5. For COMNAVSURFLANT/COMNAVSURFACE: Recommend that CG 47 class and DDG 51 class ships be tasked to: A. Inspect relay mechanically to ensure that the terminals or the clutch springs have not been damaged by over torquing. B. If in doubt of relay reliability, request technical assistance. 6. POC is Mr. N.S. Smithson, PMS 400F431, (A) 332-5981 or Comm (703) 602-5981.