🔍 Key Concepts

• Function of packing glands in a water-cooled stern tube • Why a small, controlled leakage is intentionally allowed • Difference between cooling the packing versus cooling the stern tube water/fair water

💭 Think About

• Ask yourself: What part of the system is in direct contact with the rotating shaft and subject to friction and heat? • Which component would be most damaged if it became dry and overheated? • Is the small leakage meant to move large amounts of dirt and grit, or to protect something from heat caused by friction?

✅ Before You Answer

• Identify which option focuses on the packing itself rather than the whole stern tube • Consider which part experiences frictional heating as the shaft turns • Check which choice describes a continuous, slight flow that protects a component rather than a heavy flushing action