🔍 Key Concepts

• Purpose and design of P-tanks on offshore supply vessels • Difference between fill lines, discharge lines, and purge/vent lines in liquid cargo systems • How pressure vs. gravity filling affects tank safety and structural limits

💭 Think About

• Ask yourself: Is a P-tank usually designed to be filled by pushing product under high pressure, or by allowing it to flow in a controlled way? • Think about what each line is normally used for: Which one is intended to REMOVE product, which one to ADD product, and which one to CLEAR or VENT lines? • Consider safety: Which filling method reduces the risk of overpressure or damage to the tank?

✅ Before You Answer

• Identify the primary function of the jet air/purge line on a supply boat cargo system • Confirm whether the discharge line is normally associated with loading or unloading cargo from P-tanks • Decide whether P-tanks are typically designed for gravity filling or pressurized filling, and how that relates to safe operating practice