USCG Exam PracticeThermodynamics and heat exchangers
What is the most common reason a shipboard lube-oil cooler gradually loses cooling capacity over time?
- A. Reduction in seawater temperature
- B. Increased lube-oil viscosity
- ✓ Fouling of heat-transfer surfacesCorrect
- D. Counter-flow arrangement converting to parallel flow
Why C is correct
DOE-HDBK-1018 Vol.1 §2-1 states that fouling — scale, sludge, marine growth, or oil films — adds thermal resistance and is the most common reason a cooler gradually loses capacity. Tube cleanliness is therefore a maintenance priority.
Cited:DOE-HDBK-1018 Vol.1 §2-1