Once while entering Haldia, before entering lock gate, auto starting air valve opened automatically when the engine was running in slow speed the air bottle pressure started dropping very fast. Immediately we have isolated the auto valve and also the valve fitted on the air bottle.

The problem was traced. Problem was suspected to be inside the pneumatic valves control box. The ship was in front of the lock gate, hence the problem could not be attended to immediately. The air connection for the auto valve was removed and the valve was isolated.

With manual control the ship was maneuvered till reaching berth, with the help of other air bottle.

Along side the B&W specialist was called from Singapore and two in number pneumatic actuators which were malfunctioning were changed and the problem was rectified.

It was found that lot of oil and moisture in the system. This was the reason for the malfunctioning of the pneumatic actuator. The instrument air drier/dehumidifier was not working for long time. Manual draining was not sufficient for effective draining of moisture and oil from system.

So it was realized that the instrument air drier/dehumidifier should always be kept in working condition.
hindustan institute of marine training chennai