🔍 Key Concepts

• Relationship between LCG (Longitudinal Center of Gravity) and LCB (Longitudinal Center of Buoyancy) when a vessel is on even keel with no external moments • How trim is affected when LCG is not at the same longitudinal position as LCB • Reference point for longitudinal measurements (aft perpendicular, forward perpendicular, or amidships) on stability/hydrostatic data sheets

💭 Think About

• If the DEEP DRILLER is level (no trim) and there are no environmental forces, what must be true about the relationship between LCG and LCB? • Where would you find the LCB at a draft of 58 feet in the vessel’s hydrostatic or stability data, and how is it expressed (aft or forward of amidships)? • How does a small difference between the choice values (2.23, 2.26, 2.31) help you decide which one aligns with the exact hydrostatic value at 58 feet draft?

✅ Before You Answer

• Confirm that for zero trim with no external forces, LCG and LCB must be at the same longitudinal position • Check how the test vessel’s hydrostatics define longitudinal distances: is amidships the zero point, or is it measured from an aft perpendicular with a separate amidships reference? • Verify the LCB at 58 feet draft from the stability/hydrostatic table and then match that value to the answer choices, paying attention to whether it is listed as forward of amidships or aft of amidships