What is the decrease in vertical moments for the Coastal Driller if 2.5 feet of drill water is discharged from a full drill water tank 23?

Correct Answer: Option C — 482 ft-kips

The decrease in vertical moments is calculated by multiplying the weight of the discharged drill water by the vertical distance from the baseline to the tank's center of gravity. Discharging 2.5 feet of water from the specified tank results in a reduction of 482 ft-kips of vertical moment.