FFG 7 CLASS ADVISORY NO. 06-95
SUPERSTRUCTURE WELDING
REF/A/LTR/NAVSEA/-//
REF/B/DOC/NAVSEA/-//
NARR/REF A IS FFG 7 AER N0. 13-94, PASSIVE COUNTERMEASURES (PCMS)
MATERIAL AND NON-SKID REMOVAL FOR SUPERSTRUCTURE CRITICAL WELD
INSPECTION, SERIAL NUMBER 335TH/9940 OF 19 DEC 94. REF B IS NAVSEA
DRWG 150-5604994 REV E, QUALITY ASSURANCE REQUIREMENT FOR SHIPALT
146K.//
POC/P. J. REGIS/LCDR/-/LOC: ARLINGTON VA/TEL: DSN 332-1304 X113
/TEL: (703) 602-1304 X113//
RMKS/1. THIS CLASS ADVISORY PROVIDES GUIDANCE CONCERNING WELD
REPAIR OF CRITICAL AREAS ON FFG 7 SUPERSTRUCTURES.
2. BACKGROUND
A. HISTORICALLY, THE SUPERSTRUCTURE ON FFG 7 CLASS SHIPS HAS
EXPERIENCED EXTENSIVE CRACKING. THE CAUSE OF THE CRACKING HAS BEEN
DETERMINED TO BE A COMBINATION OF HIGH DESIGN STRESS COUPLED WITH
POOR QUALITY WELDING. IN SEVERAL CASES CRACKS HAVE SPREAD ACROSS THE
02 LEVEL WEATHERDECK. THE MOST PREVALENT CRACKING OCCURS AT FRAME
200.5 ON THE 02 LEVEL.
B. SHIPALT FFG 7-86K WAS FIRST INTRODUCED TO ALLEVIATE
CRACKING PROBLEMS. THIS SHIPALT WAS NOT COMPLETELY SUCCESSFUL,
THEREFORE, SHIPALT FFG 7-146K WAS DEVELOPED AND IMPLEMENTED.
SHIPALT 146K INCORPORATES MORE STRINGENT QUALITY ASSURANCE MEASURES
AND WELDING PROCEDURES.
C. DUE TO CONCERN THAT THE HIGH STRESSES AND POOR QUALITY
WELDING MAY PRODUCE CRACKING AT OTHER AREAS OF THE FFG 7 CLASS
SUPERSTRUCTURE, POST SHIPALT 146K INSTALLATION SHIP CHECKS HAVE BEEN
UNDERTAKEN BY NSWCCD-SSES AND LBNSY TO MONITOR THE EFFECTIVENESS OF
THE ALTERATION. TO ASSIST NSWCCD-SSES AND LBNSY AND ALLOW FOR
SHIPS FORCE INSPECTION OF CRITICAL WELD AREAS, REF A WAS DEVELOPED.
THIS AER CALLS FOR THE PERMANENT REMOVAL OF PCMS AND NON-SKID FROM
CRITICAL WELD AREAS IDENTIFIED DURING POST SHIPALT 146K INSTALLATION
SHIP CHECKS. REMOVAL OF THE SPECIFIED PCMS MATERIAL WILL NOT
ADVERSELY AFFECT THE PERFORMANCE OF THE REMAINDER OF THE COATING.
D. GOOD WELD QUALITY IS MANDATORY IN THE PRESENCE OF THE HIGH
DESIGN STRESS AREAS SUCH AS FOUND ON THE FFG 7 02 LEVEL. ACHIEVING
GOOD QUALITY WHEN WELDING ALUMINUM REQUIRES METICULOUS ADHERENCE TO
CLEANLINESS AND PROCEDURES. POOR ALUMINUM WELDING WILL CRACK.
3. ACTION.
A. ALL FFG 7 CLASS SUPERSTRUCTURE WELD REPAIR WORK SHALL
CONFORM TO REF B OR NSWCCD-SSES EQUIVALENT QUALITY ASSURANCE
PROVISIONS.
B. TACK WELDING ON CRITICAL WELD AREAS OF THE SUPERSTRUCTURE
AND CORRESPONDING INTERIOR OVERHEADS AND BULKHEADS IS PROHIBITED.
SUPERSTRUCTURE CRITICAL WELD AREAS ARE DEFINED AS ANY STRUCTURAL
WELD BETWEEN FRAMES 180 AND 230.
C. NSWCCD-SSES (CODE 6233) SHALL BE CONTACTED PRIOR TO ANY
WELDING WITHIN 24 INCHES OF ANY CRITICAL WELD AREA TRANSVERSE BUTT
WELD.
D. SHIPS FORCE SHALL REPORT TO ORIG AND NSWCCD-SSES THE
FOLLOWING ITEMS IF FOUND IN THE SUPERSTRUCTURE CRITICAL WELD AREA
DURING NORMAL ROUTINE INSPECTION:
(1) ANY CRACK IN AN EXISTING TRANSVERSE BUTT WELD.
(2) ANY DECK CRACK OVER A LONGITUDINAL STIFFENER.
(3) ALL PREVIOUSLY REPAIRED CRACKS.
(4) ANY CRACK OVER 6 INCHES IN LENGTH.
(5) ANY CRACK WITHIN 24 INCHES OF A TRANSVERSE BUTT WELD.
E. SHIPS FORCE SHALL ACCOMPLISH REF A AT THE EARLIEST WINDOW OF
OPPORTUNITY.
4. FOR COMNAVSURFLANT/COMNAVSURFPAC - RECOMMEND:
A. TASKING FFG 7 CLASS SHIPS TO ADHERE TO PARA 3 ACTIONS.
B. TASKING IMA ACTIVITIES TO ADHERE TO PARA 3 ACTIONS.
5. FOR LBNSY (CODE 250.1) - ENSURE ALL SHIP ALTERATIONS UNDER
DEVELOPMENT, WHICH REQUIRE SUPERSTRUCTURE WELDING, CONFORM TO REF B
OR EQUIVALENT WELDING QUALITY ASSURANCE PROVISIONS.
6. FOR SUPSHIPS - ENSURE REF B IS ADHERED TO PRIOR TO AND DURING
INSTALLATION OF SHIPALT FFG 7-146K.
7. THIS CLASS ADVISORY HAS NO IMPACT ON EOSS, PMS, OR CMP. IT WILL
BE CANCELLED AT THE DISCRETION OF THE ORIG AND CNSL/CNSP.
8. NAVSEA POC IS JOHN STONE, PMS335TH, DSN 332-1304 X115 OR COMM
(703) 602-1304 X115. NAVSEA WELDING POC IS JOHN DORN, SEA 03M2, DSN
332-0206 OR COMM (703) 602-0206. NSWCCD-SSES STRUCTURES POC IS
MARTIN COHEN, CODE 625, DSN 443-7651 OR COMM (215) 897-7651.//
BT
FFG-7