🔍 Key Concepts

• MODU (Mobile Offshore Drilling Unit) global structural loading: what major categories of stress act on the hull/frame • Difference between applied loads from operations (weights, cargo, ballast, drilling equipment) versus external forces from nature • How class rules and design calculations group stresses: still-water/weight-induced vs environmental (sea, wind, current)

💭 Think About

• Think about which answer choice best represents forces that come from outside the unit, acting on the structure as it sits in the ocean • Ask yourself: loading stresses already include the effects of weights, ballast, and variable loads. What other major group of stresses must be added to get the total structural stress? • Consider which option describes the effects of waves, wind, and current on the MODU’s structure, rather than changes in onboard weight distribution

✅ Before You Answer

• Confirm that loading stresses already account for internal weight distribution (including ballast and variable loads) • Identify which option describes forces due to waves, wind, and current on the structure, not just onboard weights • Eliminate any choices that are simply sub‑categories of loading rather than a separate, external source of stress