🔍 Key Concepts

• Identify the direction of sea water flow through the system (from sea chest/pump toward overboard discharge). • Determine which components labeled 3, 4, 5, 6 are in series versus in parallel on the sea water side. • Remember that sea water temperature rises each time it passes through a heat exchanger that removes heat from machinery before moving to the next exchanger.

💭 Think About

• Trace the sea water piping from the pump outlet and note the sequence in which it passes through coolers 3, 4, 5, and 6—does it split or go one after another? • Ask yourself: which cooler sees already-warmed sea water that has just absorbed heat from other equipment, rather than “fresh” cool sea water directly from the pump? • Consider what each cooler is serving (lube oil, jacket water, fuel, etc.) and whether that service usually receives the coldest or a warmer grade of cooling water in system design.

✅ Before You Answer

• Verify the arrow directions or flow indicators on the sea water lines going to and from 3, 4, 5, and 6. • Confirm whether the return from one cooler becomes the inlet to another cooler (indicating series flow). • Double‑check which numbered cooler is closest to the overboard discharge on the sea water side, as this one will have the highest sea water inlet temperature in a series arrangement.