The liquid mud tanks on your vessel measure 32'L by 15'B by 8'D. The vessel's displacement is 640 tons and the specific gravity of the mud is 1.8. What is the reduction in GM due to a pair of these tanks (p/s) being slack?

Correct Answer: Option C — 1.41 feet

Free surface reduction of GM is determined by dividing the total free surface moment of slack tanks by the vessel's displacement (640 tons). Using FSM = (L × B³ × SG) / 12 for the 32' by 15' tanks containing 1.8 SG mud, the resulting combined P/S free surface loss is 1.41 feet.