356. On a vessel displacing 8,000 tons, what is the reduction in metacentric height due to free surface when a tank 45 feet long and 45 feet wide is partly filled with salt water?

The reduction in metacentric height is calculated by dividing the transverse moment of inertia of the free surface by the vessel's displacement volume, which is 280,000 cubic feet for a 8,000-ton vessel in salt water. With a tank length and breadth of 45 feet, the transverse moment of inertia is 341,718.75 square feet, resulting in a reduction of 1.22 feet.