🔍 Key Concepts

• Lightweight condition of a vessel or offshore unit (weight of the structure itself without variable loads such as fuel, water, drill pipe, etc.) • Meaning of transverse moment in stability and trim calculations (moment about the centerline, often related to list or off-center weights) • How sign and magnitude of a moment (positive, negative, or zero) reflect the presence, direction, and balance of off-center weights

💭 Think About

• Think about what it would mean physically if the transverse moment of the lightweight condition were very large versus very small. How would that affect the unit’s natural tendency to list? • Consider what a negative transverse moment would imply about the assumed reference direction and the distribution of weight relative to the centerline. • Ask yourself whether, in a properly defined lightweight condition for a symmetric drilling unit like DEEP DRILLER, you would expect a significant built-in off-center moment, or for it to be close to balanced.

✅ Before You Answer

• Check whether the DEEP DRILLER is assumed to be transversely symmetrical in its design and lightweight condition; if so, what does that suggest about the transverse moment? • Verify how the reference axis and sign convention for transverse moments are defined in the stability booklet or problem setup (port vs. starboard positive). • Confirm whether the problem is likely testing your understanding of a balanced lightweight condition versus a condition with a large inherent list-causing moment.