MAIN ENGINE AIR COOLER LEAKING
The ship, loaded ammonia as cargo at Persian Gulf , she was proceeding to discharge to Mangalore port , just 6 -7 hrs before while berthing to Mangalore port F.W cooling pump low pressure alarm came, checked the pump and found pressure too low , changed over to stand by pump , it was running for few mints in satisfactory condition, but pressure started fluctuating in a short time. Mean while purging of the first pump was tried. No success. Checked the entire FW system, could not locate the problem. The speed was reduced and it was found the CW pressure increasing. Informed the bridge and the RPM was reduced to F.Ahd speed. Though the pressure was not normal, but it was maintaining at a satisfactory level.
Luckily, the ship was almost reaching Mangalore, hence 1 hr notice was given for arrival.
The ship had a centralized cooling system. The ship was berthed without any problem. But during maneuvring, it was observed that whenever scavenge pressure increased, the CW pressure was found to decrease. Hence concluded that the air cooler may be at fault.
On berthing, immobilization was taken, Air Cooler was taken out, and found three tubes holed (tiny holes). Same plugged, and the cooler boxed back. The next voyage was peaceful and the problem did not arise further.