🔍 Key Concepts

• Butterworth tank cleaning process sequence and purpose of each step • Meaning of slops (mixture of wash water and cargo residues) and why timing of discharge matters • Role of a drop schedule in tank washing operations

💭 Think About

• Think about what is happening inside the tank at different stages of the Butterworth process—when is most of the residue actually loosened and suspended in the wash water? • Consider when it is safest and most efficient to remove slops so you don’t re-contaminate surfaces you’ve already washed. • Ask yourself at what point in the operation the slops are at their maximum and most concentrated, and how that relates to the listed choices.

✅ Before You Answer

• Identify exactly what a drop schedule is and when it occurs during Butterworth cleaning. • Distinguish between the moment the process starts, the period during washing, and the time after washing stops. • Verify which practice prevents cleaned areas from being re-coated with dirty wash water and minimizes the volume of slops retained on board.