Q5.
a) Describe the actions and checks required to ensure that a crosshead main propulsion engine may be operated in a slow steaming condition.(8)
b) Explain the problems which may arise during a prolonged period of slow steaming
(4)
c) Explain what actions should be taken before and after the engine is returned to normal operation after a period of slow steaming(4)
Reference Answer
### a) Actions and Checks for Slow Steaming Operation To ensure a crosshead main propulsion engine can be operated safely and efficiently in a slow steaming condition (typically below 50% MCR), a series of specific actions and continuous checks are required. These actions are guided by the engine manufacturer's recommendations and focus on managing combustion, lubrication, and thermal stresses. **1. Turbocharger and Scavenge Air System Management:** * **Engage Auxiliary Blowers:** At low engine loads, the exhaust gas energy is insufficient to drive the turbocharger at a speed that provides adequate scavenge air pressure. Auxiliary electric blowers must be started, typically automatically below 25-30% load, to augment the air supply.
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