The liquid mud tanks on your vessel measure 22'L by 16'B by 7'D. The vessel's displacement is 568 T and the specific gravity of the mud is 1.6. What is the reduction in GM due to 2 of these tanks being slack?

Correct Answer: Option C — 1.18 feet

Free surface effect reduces effective transverse metacentric height (GM). The reduction is determined by multiplying the number of slack tanks by (l × b^3 × SG) / (12 × Displacement). For two tanks measuring 22'x16'x7' with 1.6 SG mud at 568 T displacement, the loss in GM is 1.18 feet.