While underway in a field move with the lower hulls awash, a semisubmersible has a maximum allowable KG of 63.69 feet; KMT is 65.12 and KML is 64.92. The KGT is 56.13 and KGL is 55.89. What is the margin on the maximum allowable KG?

Correct Answer: Option B — 7.56 feet

Margin of stability is the mathematical difference between the maximum allowable vertical center of gravity (KG) and the actual operating KG. Subtracting the actual KGT (56.13 feet) from the maximum allowable KG (63.69 feet) yields a positive operational safety margin of 7.56 feet.