🔍 Key Concepts

• MARPOL applicability to mobile offshore drilling units (MODUs), especially when they are treated like ships • The purpose of the International Oil Pollution Prevention (IOPP) Certificate • When international conventions tend to ‘switch on’ – domestic moves vs. international voyages between States that are parties to the convention

💭 Think About

• Ask yourself: Is MARPOL (and the IOPP Certificate) primarily concerned with any movement at all, or with certain kinds of voyages? • Think about how a MODU is viewed legally when it travels to another country’s port versus when it stays within one country’s offshore area. • Which of the choices actually triggers an international convention requirement, rather than just normal U.S. domestic offshore operations?

✅ Before You Answer

• Verify which situations involve an international voyage between MARPOL Parties and which are purely domestic operations. • Confirm whether simply moving within U.S. waters or operating on the U.S. Outer Continental Shelf is, by itself, enough to activate the IOPP Certificate requirement under MARPOL. • Double‑check how a mobile offshore drilling unit (MODU) is defined and when it is treated as a ship for the purposes of MARPOL certificates.