🔍 Key Concepts

• Design Limits of Legs Chart sections and what each curve (A, B, etc.) usually represents • Difference between operating limits during normal transit vs. elevated/working condition limits • How variable load, environmental load, and leg strength are each defined on a jack‑up or similar unit

💭 Think About

• Ask yourself: during normal transit (legs up and the unit being moved), which factor is most likely to govern the safe operating envelope shown on a legs chart? • Consider which of the choices would typically change with cargo and consumables, and which would be more tied to sea state, wind, and waves, or to the inherent capacity of the structure. • Think about how a Design Limits of Legs Chart would be used by the master or OIM when deciding if it is safe to move the unit in given conditions—what is Curve B telling them not to exceed?

✅ Before You Answer

• Verify in the manual how normal transit is defined (legs position, towing or self‑propelled, and typical draft). • Check which parameter the chart’s Curve B is plotted against on each axis (e.g., significant wave height, wind speed, draft, or variable load). • Confirm whether Curve B is described as a limit based on structural capacity of the legs, on environmental loading, or on the amount of carried load.