🔍 Key Concepts

• Purpose and location of an emergency or split inflatable seal on a propeller shaft sealing arrangement • Normal function of the primary shaft seal versus backup/emergency sealing devices • What operations can and cannot safely be done with the vessel afloat around a shaft seal

💭 Think About

• Think about when you would need an extra, inflatable seal aft of the primary seal—what kind of emergency or maintenance situation would make this useful? • Consider which choices describe a temporary/emergency backup function versus normal, continuous-duty functions of the primary seal. • Ask yourself: which option matches what an inflatable device can realistically do in a shaft tunnel without overcomplicating the system?

✅ Before You Answer

• Check which option clearly describes a backup or emergency sealing function, not a normal routine function of the primary seal. • Verify whether a split inflatable seal is intended for continuous operation or temporary use under special conditions. • Eliminate any choices that describe functions already handled by standard stuffing boxes, cooling water systems, or the primary seal itself.