The liquid mud tanks on your vessel measure 18'L by 10'B by 6'D. The vessel's displacement is 944 T and the specific gravity of the mud is 1.9. What is the reduction in GM due to a pair of these tanks (p/s) being slack?

Correct Answer: Option B — .16 foot

Smaller tank breadths drastically reduce free surface inertia since FSM varies with the cube of the breadth. For 18'L by 10'B tanks carrying 1.9 SG mud on a 944 T vessel, the computed free surface correction yields a minimal 0.16-foot reduction in available GM.