Your vessel displaces 562 tons and measures 121'L x 29'B. You ship a large wave on the after deck. What is the reduction to GM due to free surface before the water drains overboard, if the after deck measures 46'L x 29'B and the weight of the water is 41 tons?

Correct Answer: Option A — 4.43 feet

The virtual loss of metacentric height from water on deck is determined by the transverse inertia of the flooded area divided by displacement volume. For a 562-ton vessel with 41 tons of water on a 46'x29' after deck, this yields 4.43 feet.