🔍 Key Concepts

• Follow the sea water path from the sea chest/sea water pump discharge all the way to the overboard, ignoring line and valve losses. • Identify which components are actually heat exchangers (sea water on one side, another fluid on the other; no mixing). • Count each separate cooler body the sea water flows through as one distinct pressure drop, even if there are bypass lines or parallel branches.

💭 Think About

• Starting at the sea water pump, how many different pieces of equipment does the sea water enter where it gives up heat to another system (lube oil, jacket water, fuel, etc.)? • Look carefully at the large combined unit in the dashed box: does the sea water pass through one shell or more than one physically separate cooler section? • On the right-hand side, does the sea water pass through an additional cooler before going overboard, or is that device something else (like a separator or tank)?

✅ Before You Answer

• Make sure you only count true heat exchangers (two-fluid, no-mixing coolers), not pumps, filters, or heaters. • Verify whether the combined main cooler (items 23 and 24) should be counted as one or two distinct exchangers for sea water flow. • Confirm whether sea water actually flows through the device near items 21–22 and whether it functions as a cooler, adding another pressure drop.