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?

Correct Answer: Option D — 6.14 feet

Accumulated water on deck compromises transverse stability through virtual elevation of the center of gravity. For a 689-ton vessel retaining 62 tons of water within a 65' by 31' after deck space, the resulting GM reduction is 6.14 feet.