Question 43 OSE01 - Chief Engineer - OSV

The Correct Answer is A. **Explanation for Option A (Correct Answer):** Rolling an engine with cylinder test valves open is a critical safety and pre-start procedure designed to confirm the cylinders are clear of incompressible fluids (like water or lube oil) that might have accumulated. The discharge of a "rather large amount of water" is a severe indication of a major fault. Possible causes include a cracked cylinder liner, a failed cylinder head gasket, a leaking air cooler, or a major issue with the jacket water cooling system leaking directly into the combustion space. Starting the engine under these conditions (even temporarily) is extremely dangerous, as the underlying fault could lead to catastrophic engine failure (e.g., hydraulic lock causing bent connecting rods or a cracked engine block) or severe damage to internal components. The appropriate and mandatory response is to immediately stop all starting attempts and diagnose and repair the source of the water ingress before allowing the engine to be operated. **Why the other options are incorrect:** **B) Start the engine, but run the engine with the cylinder test valves cracked slightly open.** This option attempts to mitigate the risk but does not address the fundamental problem. Running the engine with water ingress will cause rapid component wear (corrosion, washing away of lubrication) and still carries a high risk of catastrophic failure (hydraulic lock) if the ingress rate is high. Cracking the test valves open slightly is not a long-term or safe operating procedure and may only partially relieve pressure, while the engine is simultaneously being destroyed internally. **C) Start the engine, but maintain the jacket water expansion tank level higher than normal.** This action is irrelevant to solving the problem of water ingress into the cylinders. Raising the expansion tank level might marginally increase system pressure, but it does nothing to stop the leak into the combustion space. Furthermore, if the expansion tank level is raised excessively, it could potentially overload the overflow system. **D) Start the engine, but monitor all fluid levels very closely, especially that of the jacket water.** While monitoring is always necessary, starting the engine knowing a serious fault exists is an unacceptable risk. Monitoring the fluid loss (especially jacket water) would only confirm that the engine is actively being damaged or is at risk of failure. This approach substitutes proper maintenance and repair with dangerous risk-taking and monitoring a failure in progress.