Question 68 OSE01 - Chief Engineer - OSV

The Correct Answer is D ### 2. Explanation of why option D is correct: Option D states: "Movement of the mechanical slave remote control station lever directly shifts the pilot house pneumatic master control station lever control valve spool by the action of a chain or cable which results in pneumatic shifting of the clutch actuator 4-way control valve to the ahead direction." This is the correct operational sequence for interfacing a mechanical slave station with a primary pneumatic master control system. The mechanical slave station (which might be located on a bridge wing, a secondary steering station, or the local engine room station) does not typically have its own pneumatic control components but rather uses a physical linkage (chain or cable) to operate the main *Master Control Station* located in the pilot house or main console. When the slave lever is moved: 1. **Mechanical Action:** The chain or cable transmits this physical movement. 2. **Actuation Point:** This movement physically repositions the control valve spool located inside the Pilot House Master Control Station. 3. **Pneumatic Output:** Repositioning the master spool directs compressed air (the pneumatic signal) to the final actuator (the clutch actuator 4-way control valve), causing the vessel’s propulsion clutch to engage in the ahead direction. ### 3. Explanation of why the other options are incorrect: **A) Movement of the mechanical slave remote control station lever directly shifts the pneumatic remote control station lever control valve spool by the action of a chain or cable which results in pneumatic shifting of the clutch actuator 4-way control valve to the ahead direction.** This option uses vague terminology ("pneumatic remote control station"). While technically the master station is a pneumatic remote station, option D is superior because it specifically identifies the station being controlled as the "pilot house pneumatic **master** control station," clarifying its primary role in the system hierarchy. **B) Movement of the mechanical slave remote control station lever directly shifts the engine room control station lever control valve spool by the action of a chain or cable which results in pneumatic shifting of the clutch actuator 4-way control valve to the ahead direction.** The Engine Room Control Station (ERCS) is often a local, backup control point. While sometimes linked to a secondary station, the mechanical slave station is designed to interface with and take advantage of the *Master* control system (usually in the Pilot House) to initiate the pneumatic signal. The Pilot House Master Station is the central distribution point for control signals. **C) Movement of the mechanical slave remote control station lever directly shifts the clutch actuator 4-way control valve to the ahead direction by the action of a chain or cable.** This option is incorrect because it implies the mechanical linkage runs all the way to the engine room and physically moves the final clutch control valve. The system is described as a *pneumatic* propulsion control system. The mechanical linkage’s purpose is to start the flow of air (by moving the spool valve at the master station), not to replace the compressed air entirely by mechanically shifting the large clutch actuator valve itself.