CG 47 CLASS ADVISORY NR 06-93A1
INTERIM FLUSHING PROCEDURES FOR PRAIRIE AND MASKER AIR COOLERS
REF/A/RMG/AEGIS PROG MGR/051143ZMAY93//
REF/B/RMG/USS PRINCETON/091855ZJUN93//
NARR/REF A IS CG 47 CLASS ADVISORY 06-93. REF B IS REPORT OF
CONTAMINATION OF FRESH WATER SYSTEM WHEN FLUSHING PRAIRIE AIR
COOLER.//
RMKS/1. THIS CLASS ADVISORY AMENDMENT PROVIDES CLARIFICATION OF
REF A INTERIM FRESH WATER FLUSHING PROCEDURES FOR THE PRAIRIE AND
MASKER AIR COOLERS AS A RESULT OF CONTAMINATION OF FRESH WATER
SYSTEM REPORTED BY REF B. BUTTERFLY VALVE LEAKBY IS A KNOWN
PROBLEM ON CG 47 CLASS SHIPS. THEREFORE, SPECIFIC GUIDANCE FOR
SHIPS WITH SEVERE BUTTERFLY VALVE LEAKBY IS ALSO PROVIDED.
2. CONTAMINATION REPORTED BY REF B WAS CAUSED BY HARD PIPING A
HOSE FROM A DEEP SINK TO A GAUGE LINE AFT OF THE PRAIRIE AIR
COOLER SEA WATER INLET VALVE. EXCESSIVE LEAKBY OF BUTTERFLY
ISOLATION VALVES THEN RESULTED IN SEAWATER BEING FORCED INTO THE
FRESH WATER ATTACHMENT TO THE HOT WATER LINE. THE INTENT OF REF
A PARA 3.A.(1) WAS TO FILL THE COOLER THROUGH THE VENT PLUG HOLE
WITHOUT HARD PIPE ATTACHMENT.
3. THE FOLLOWING GUIDANCE PROVIDES CLARIFICATION OF FLUSHING
PROCEDURES IN REF A PARA 3.A.(1) FOR SHIPS NOT EQUIPPED WITH
COOLERS MODIFIED WITH FILL/DRAIN VALVES:
A. USE A HOSE TO FILL COOLER THROUGH THE VENT PLUG HOLE
WITH FRESH WATER UNTIL WATER APPEARS AT THE VENT.
B. DO NOT HARD PIPE THE FRESH WATER HOSE TO THE COOLER.
SALT WATER CONTAMINATION OF THE POTABLE WATER SYSTEM MAY RESULT.
ENSURE AN AIR GAP EXISTS BETWEEN COOLER VENT PLUG HOLE AND FRESH
WATER HOSE TO PREVENT POTABLE WATER SYSTEM CONTAMINATION.
C. BUTTERFLY VALVE LEAKBY IS POSSIBLE. IF COOLER ISOLATION
VALVE LEAKBY IS GREAT ENOUGH TO PREVENT DRAINING OF THE COOLER,
REINSTALL VENT/DRAIN PLUGS AND PERFORM SALT WATER LAY-UP IAW REF
A PARA 3.A.(2). FRESH WATER LAY-UP IS THE PREFERRED METHOD EVEN
IF THERE IS MINOR VALVE LEAKBY. ALTHOUGH NOT AS EFFECTIVE AS A
FRESH WATER LAY-UP, THE SALT WATER LAY-UP WILL REDUCE THE AMOUNT
OF CORROSION DAMAGE OCCURRING TO THE COOLER.
4. ECP 47-4811 IS BEING DEVELOPED WHICH WILL INSTALL ADDITIONAL
ISOLATION (BALL OR GLOBE) VALVES, VENTS, DRAINS AND FILL
CONNECTIONS TO 33 SEAWATER COOLERS, INCLUDING THE PRAIRIE AND
MASKER COOLERS. THIS WILL ALLOW SHIPS TO EFFECTIVELY ISOLATE THE
COOLERS FOR PREVENTIVE AND CORRECTIVE MAINTENANCE. THE ECP WAS
APPROVED AT THE JUN 93 TECHNICAL SCOPE REVIEW AND WILL BE
SCHEDULED FOR THE OCT 93 CONFIGURATION CONTROL BOARD. CG 70-73
ARE TENTATIVELY SCHEDULED TO RECEIVE THE ECP DURING PSA. BACKFIT
OF THESE MODS TO THE PRAIRIE AND MASKER COOLERS ON CG 47-69 WILL
BE INCLUDED IN SHIPALT 47-435K WHICH IS CURRENTLY UNDER
DEVELOPMENT BY ACPY. TENTATIVE SCHEDULE IS TO START INSTALLATION
OF SHIPALT 47-435K IN FY 96.
5. ORIG POC IS MR. N. SMITHSON, PMS400F511, DSN 332-5959 OR COMM
(703) 602-5959.//
CG-47