🔍 Key Concepts

• stern tube stuffing box purpose and how it keeps water out while allowing shaft rotation • how packing (soft packing rings) is cooled and lubricated • difference between allowing slight leakage vs. fully tightening a gland

💭 Think About

• Think about what actually removes friction heat from the packing as the shaft turns inside the stern tube. • What happens to packing temperature if you stop all water from getting through the stuffing box? • Which choice best matches normal practice on conventional packed stuffing boxes, as seen on older or simpler vessels?

✅ Before You Answer

• Verify how packing in a stuffing box is both cooled and lubricated in service. • Check which option would most likely cause overheating and rapid wear of the packing and shaft sleeve. • Identify which answer describes a controlled condition, not an extreme or abnormal condition (totally dry or heavily forced cooling).