313. On a vessel of 5,000 tons displacement there are two slack tanks of acid (SG 1.8). Each tank is 30 feet long and 20 feet wide. What is the reduction in metacentric height due to free surface with the vessel in sea water (SG 1.025)?

The reduction in metacentric height due to free surface is calculated by considering the specific gravity of the liquid relative to seawater, the second moment of area of the free surface, and the vessel's displacement. For two slack tanks of acid, with dimensions 30 feet by 20 feet, a specific gravity of 1.8, and a displacement of 5,000 tons, the reduction in metacentric height is approximately 0.40 feet.