A shaft alley divides a vessel's cargo hold into two tanks, each 20 ft. wide by 60 ft. long. Each tank is filled with saltwater below the level of the shaft alley. The vessel's displacement is 7,000 tons. What is the reduction in GM due to free surface effect?

Correct Answer: Option B — .33 feet

Longitudinal bulkheads or shaft alleys subdivide free surfaces, significantly diminishing transverse shifting moments. For two 20'x60' tanks on a 7,000-ton vessel, the recalculated inertia yields a reduced metacentric height loss of 0.33 feet.