🔍 Key Concepts

• Definition of true mean draft on a floating MODU (mobile offshore drilling unit) • Difference between observed drafts (read on draft marks) and calculated drafts/displacement from hydrostatic data • Role of displacement and hydrostatic curves in relating draft to vessel weight

💭 Think About

• Which option ties the draft directly to the vessel’s actual weight in the water (displacement) rather than where it is read or geometrically averaged? • Is true mean draft based on physical draft mark readings, or on the hydrostatic relationship between draft and displacement? • On a MODU with trim and possibly unequal loading, which definition of draft will best represent the unit’s overall immersion for stability and strength calculations?

✅ Before You Answer

• Identify which choice clearly connects draft to displacement from hydrostatic data • Distinguish between a simple average of readings and a draft tied to the vessel’s actual buoyant support (weight) • Check which option would remain valid even if individual draft readings are distorted by hog, sag, or local conditions