Because there is a possibility of fuel oil being discharged overboard from a full fuel oil tank, it is decided to transfer 25 kips from tank 14 to tank 13. See COASTAL DRILLER Sample Load Form Number 1 (Rig Move). What would be the change in longitudinal free surface moments?

Correct Answer: Option C — 674 ft-kips increase

Longitudinal free surface moments are a function of tank geometry and are calculated using the inertia of the free surface area multiplied by the specific gravity. Transferring weight between designated tanks alters the free surface moments, resulting in a 674 ft-kips increase.