345. Your vessel displaces 689 tons and measures 123'L x 31'B. You ship a large wave on the after deck which measures 65'Lx 31'B. The weight of the water is estimated at 62 tons. What is the reduction in GM due to free surface before the water drains overboard?

The reduction in GM due to free surface is calculated using the free-surface formula, considering the increased displacement resulting from the shipped water. The second moment of area for the rectangular ponded water and the new underwater volume are determined, yielding a GM reduction of 6.14 feet.