🔍 Key Concepts

• Purpose of preload and dump valves on a jack-up or similar mobile offshore drilling unit (MODU) • What happens to buoyancy and stability after preload water is discharged • Normal post-preload configuration of ballast and dump systems for safe operations

💭 Think About

• Think about why preload water is used in the first place and what the dump valves are doing during that operation. • After preload is finished and the water has been discharged, what condition do you want the hull and tanks to be in for normal operations? • Consider whether any option would be unsafe or impractical as a standard operating step after every preload discharge.

✅ Before You Answer

• Which choices would leave the unit in a safe, controllable ballast condition after preload? • Which options would be impractical or unsafe to perform routinely (e.g., every time preload is discharged)? • Verify which action best prevents unintended flooding or loss of watertight integrity after the preload phase.