The liquid mud tanks on your vessel measure 20'L by 18'B by 7'D. The vessel's displacement is 986 T and the specific gravity of the mud is 1.6. What is the reduction in GM due to a pair of these tanks (p/s) being slack?

Correct Answer: Option C — .88 foot

Transverse virtual rise of the center of gravity caused by slack liquids is evaluated via free surface moments. For a P/S pair of 20'L by 18'B mud tanks with 1.6 SG liquid on a 986 T displacement vessel, the aggregated free surface correction results in a 0.88-foot reduction in GM.