🔍 Key Concepts

• Jack-up rig leg extraction behavior when lifting legs from seabed • What a level indicator (rig inclination/trim list indicator) actually measures on a jack-up unit • Differences between legs free, punch-through, and stuck legs conditions

💭 Think About

• Think about what would physically cause the rig to change inclination (list/trim) as legs are being raised from the seabed. • Consider whether a punch-through event is associated with sudden penetration or withdrawal of the legs and how that affects the hull’s motion. • Ask yourself: if one or more legs are still holding more load than the others during extraction, what would the level indicator show compared to when all legs are carrying equal or decreasing loads.

✅ Before You Answer

• Identify what a punch-through actually is: does it occur on penetration, extraction, or both? • Clarify what the level (inclination) indicator responds to: changes in hull attitude versus leg load readings. • For each choice, picture the rig and legs during extraction and ask: would this condition likely make the hull tilt more (increasing level indication) or settle more evenly (stable/steady indication).