🔍 Key Concepts

• Follow the sea water flow path from sea chest/intake to overboard discharge. • Identify the difference between the sea water (open) circuit and the jacket water (closed) circuit in the drawing. • Recognize the pump symbols and what each is connected to (cooler, engine, or tank).

💭 Think About

• Start at the point where sea water enters the system from the sea. Which line clearly represents this, and what components does it pass through before going overboard? • Which numbered pump is located in series with the sea water side of the main engine cooler (item 24), rather than in the fresh water/jacket water loop? • Look at pumps 7, 8, 15, and 20: for each, ask yourself, does this pump move water through the sea water side of the cooler, or does it serve another subsystem such as jacket water or a drain/transfer line?

✅ Before You Answer

• Verify which lines are sea water by finding the sea inlet/overboard discharge and tracing that path only. • Confirm which side of cooler 24 is the sea water side and which is the jacket water side; the sea water pump must be on the sea water side. • For each candidate pump (7, 8, 15, 20), double‑check what components are upstream and downstream of it; the correct pump should be directly associated with the sea water circuit, not with tanks or internal engine circulation.