🔍 Key Concepts

• Lightweight displacement vs. vertical center of gravity (KG) for DEEP DRILLER • How total vertical moment is obtained from the stability booklet table (Σ w × z for all lightweight items) • Why the sign (positive/negative) of the vertical moment depends on the reference point (baseline)

💭 Think About

• From the lightship data page, identify the lightweight displacement and the KG, then think about how these two values combine to give a total lightweight vertical moment. • Ask yourself: is the reference for vertical moments the keel/baseline, and would that make KG a positive or negative distance in this vessel’s coordinate system? • Compare the order of magnitude: which options are realistically in the range of "displacement × KG" for a drilling unit of this size?

✅ Before You Answer

• Verify the lightweight displacement (long tons) for DEEP DRILLER from the data table before doing any calculation. • Confirm the KG value and sign convention used in the booklet (is KG above baseline positive or negative?). • Multiply displacement × KG and make sure the result’s units (ft-long tons) and sign (positive/negative) are consistent with the vertical moment definition used on the illustration.