Question 29 OSE01 - Chief Engineer - OSV

The Correct Answer is A. **Explanation for Option A (Correct Answer):** The symptom is that the astern clutch fails to engage *only* from the engine room (ER) control station, but works correctly from *all remote-control stations*. A totally pneumatic propulsion control system uses pilot air signals generated by the control levers to activate the main components (like the clutch actuator valves). If the pilot port for the astern engagement within the control lever mechanism at the ER station is blocked, the control lever cannot generate the necessary astern pilot air signal when operated locally in the engine room. Consequently, the astern clutch will not engage when commanded from the ER station. Since the remote-control stations (like the bridge) operate via their own separate pilot air circuits, and these circuits bypass the ER control lever's pilot generation mechanism, they can still successfully send the required signal to the clutch actuator, allowing the astern clutch to engage properly when commanded remotely. This perfectly matches the observed symptoms. **Explanation for Incorrect Options:** **B) The clutch actuator 4-way control valve at the clutch control panel has a restricted astern clutch quick exhaust port opening.** A restriction in the quick exhaust port would cause the clutch to disengage *slowly* or fail to disengage properly, but it would not prevent the initial engagement signal (pilot air) from reaching the valve or prevent engagement itself. Furthermore, since this component is common to all control stations (local and remote), if it were faulty, the astern engagement would be affected regardless of where the command originated. **C) The local/remote transfer valve at the engine room control station has a blocked local port.** If the local port on the transfer valve were blocked, the ER control station would be unable to take control of *any* function (ahead or astern), or it would fail to send any signals to the main actuators. Since the symptom only specifies a failure of *astern* engagement, and implies that the ER station might still be able to command ahead (or other functions), a generalized fault in the local/remote transfer valve is unlikely to be the cause. **D) The astern clutch engagement pilot air tubing has separated from the clutch actuator 4-way control valve at the clutch control panel.** The pilot air tubing separation would prevent *any* astern engagement signal from reaching the clutch actuator valve, regardless of whether the signal originated locally (ER) or remotely (bridge). Since the astern clutch engages properly from remote stations, the issue must be localized to the ER station's control signal generation, not the common piping or actuator valve connections.