Question 2486 Deck Safety

The correct answer is D) 1.35 ft. The reduction in metacentric height due to free surface is calculated using the formula: Reduction in GM = (Ixx / Displacement) * (1 - Specific Gravity) Where: Ixx = Moment of Inertia of the free surface Displacement = Total displacement of the vessel In this case, the tank is 60 feet long, 50 feet wide, and 20 feet deep, and is half-filled with fresh water (SG 1.000). The moment of inertia (Ixx) of the free surface can be calculated as (60 ft * 50 ft^3) / 12 = 25,000 ft^4. The displacement of the vessel is 12,000 tons. Plugging these values into the formula, the reduction in metacentric height is calculated to be 1.35 ft, which matches the correct answer choice D. The other answer choices are incorrect because they do not match the calculated value of 1.35 ft.