🔍 Key Concepts

• KG (height of center of gravity) and how it affects stability limits • How to compare the actual KG from the load form to the maximum allowable KG while drilling from the stability data • Understanding that the margin is the numerical difference between two KG values

💭 Think About

• From Sample Load Form #3, identify the vessel’s calculated actual KG in the drilling condition. What is that number? • From the appropriate stability table or curve for DEEP DRILLER, find the maximum allowable KG while drilling for the same displacement/condition. How is that value given? • Once you have both values, how do you express the safety margin between them, and what units must it be in?

✅ Before You Answer

• Be sure you are comparing KG to KG (not GM or freeboard) and that both values are for the drilling condition at the correct displacement • Verify that you are reading the correct column/row on the stability table specifically labeled for drilling (not survival, transit, or preloading) • Double‑check the subtraction order when finding the margin: confirm whether you should use max allowable KG minus actual KG or the reverse, and ensure the result is a positive safety margin in feet