🔍 Key Concepts

• Heat transfer surface area and how fins affect it • The purpose of a fuel oil heater in a marine fuel system • Relationship between surface area and thermal efficiency

💭 Think About

• Ask yourself: What physical effect do fins on a tube have on its outside surface? • Which choice best matches the main purpose of heating fuel oil before it reaches the burners? • Do fins normally restrict flow inside the tube, or do they mostly affect what happens outside the tube?

✅ Before You Answer

• Verify which option directly relates to heat exchange or heat transfer rather than flow or cleanliness • Eliminate any choice that describes a function that normally occurs inside the tube rather than on its outer surface • Check which choice would help ensure more complete combustion and better fuel economy