The DEEP DRILLER, at a draft of 60 feet, has 35,000 ft-tons of longitudinal moments. How much ballast should be transferred between tanks 1P and 10P to level the unit longitudinally?

Correct Answer: Option C — 165.3 long tons

Longitudinal stability calculations utilize longitudinal moment changes divided by the longitudinal distance between tank centers. Transferring 165.3 long tons between tanks 1P and 10P generates the exact moment required to correct 35,000 ft-tons at the given draft.