🔍 Key Concepts

• Flow path of a typical marine lube oil system from sump to bearings and back • Purpose of a sight glass (bull's-eye) in monitoring oil flow and condition • Difference between pump suction/discharge lines and gravity tank lines

💭 Think About

• On which part of the system is it most critical for the engineer to visually confirm that oil is definitely flowing? • Would a sight glass normally be placed on a line under suction, pressure, or low-pressure gravity flow? Why? • Think about where oil quality (clarity/air bubbles/foaming) is easiest to observe in the system.

✅ Before You Answer

• Identify which line would have steady, visible flow that can be easily observed by the engineer • Consider which line is most accessible and safe to visually monitor during normal operation • Eliminate any lines where a sight glass might be unreliable because of vapor, aeration, or unstable flow