Question 17 QMED03 - Oiler

The Correct Answer is B **Why Option B ("vane type steering gear") is correct:** Illustration GS-0116 depicts a common type of modern marine steering apparatus. This device uses a rotor mounted directly on the rudder stock that moves within a fixed housing (stator). Pressurized hydraulic fluid is introduced into the chambers created by fixed vanes (on the stator) and moving vanes (on the rotor). By changing which chambers receive fluid pressure, the rotor is forced to rotate, thereby turning the rudder stock. This specific design is characteristic of a vane type steering gear (often referred to as a rotary vane steering gear) and is widely used on commercial vessels. **Why the other options are incorrect:** * **A) mechanical shaft seal:** A mechanical shaft seal is a component used to prevent leakage along a rotating shaft (e.g., a pump or propeller shaft). It typically consists of precision-machined stationary and rotating faces held together under pressure. The illustration clearly shows a large hydraulic actuator for angular movement, not a sealing mechanism. * **C) diesel engine motor mount:** A motor mount (or engine mount) is a passive structure or device (often incorporating rubber isolators) used to secure an engine to the ship's foundation while absorbing vibration. It does not contain hydraulic vanes or chambers for actuation. * **D) oil scraper ring stuffing box for a crosshead engine:** This component is part of the cylinder lubrication and sealing system of a large two-stroke crosshead diesel engine. It is positioned where the piston rod passes through the crankcase diaphragm plate. Its function is to scrape lubricating oil from the piston rod and prevent oil contamination. It is a linear sealing device, not a rotary hydraulic actuator.