🔍 Key Concepts

• Crude Oil Washing (COW) purpose on tankers • How Butterworth systems are used for tank cleaning • Difference between tank cleaning vs oil purification or bilge cleaning

💭 Think About

• Ask yourself: On a tanker, what is the main reason we use crude oil wash instead of water in cargo tanks? • Which choices describe a process used INSIDE cargo tanks during discharge, and which describe unrelated systems? • Does COW have anything to do with treating oil quality, or is it about cleaning tank surfaces and improving cargo outturn?

✅ Before You Answer

• Identify which options involve cargo tank cleaning rather than oil treatment or bilge cleanup • Check your memory: COW is usually done during discharge of crude oil cargo using the ship’s existing cargo handling system and fixed tank-cleaning machines • Eliminate any option that talks about purifying oil or bilge cleaning, as that is not the function of COW