Question 58 OSE02 - Assistant Engineer - OSV

The Correct Answer is A. **Explanation for A (Engine low lube oil pressure trip/alarm device):** The engine low lube oil pressure trip or alarm is specifically designed with a time delay. This delay is crucial because sudden, momentary drops in lube oil pressure can occur naturally during ship maneuvers, sudden changes in engine load, or due to the temporary lifting of relief valves, especially in large, complex lubrication systems. If the engine tripped instantly upon a slight, momentary pressure drop, it would lead to frequent, unnecessary shutdowns. The time delay (typically a few seconds) ensures that the trip/alarm only activates if the low pressure condition is sustained, indicating a genuine failure of the lubrication system that poses a serious risk to the engine bearings and moving parts. **Explanation for why other options are incorrect:** * **B) Engine coolant high temperature alarm device:** While critical, high temperature alarms typically do not require a time delay. Temperature changes are generally slower than pressure changes. An immediate alarm is desired as soon as the set point is reached, giving the operator maximum time to react before critical damage occurs (like piston seizure or liner cracking). * **C) Engine crankcase high pressure trip/alarm device:** This device (often a crankcase oil mist detector or an actual pressure switch) monitors for explosive conditions caused by internal failures (like a hot spot or bearing failure). If high crankcase pressure or oil mist density is detected, it indicates an immediate and severe danger of a crankcase explosion. Consequently, the trip/alarm must activate instantly without delay to stop the engine before a catastrophic event occurs. * **D) Engine overspeed trip/alarm device:** An engine overspeed condition (where the engine RPM exceeds a safe limit, usually by 15-20%) represents an immediate and extreme danger of mechanical disintegration due to excessive centrifugal forces. There must be absolutely no time delay associated with the overspeed trip. It is designed to actuate instantly to prevent the engine from destroying itself.