237. Your vessel measures 131 feet long by 20 feet in beam. If the natural rolling period at a draft of 8'-03″ is 6 seconds, what is the GM?

The correct metacentric height (GM) is 2.15 feet, determined by applying the empirical rolling-period formula T = 0.44B/√GM, where B is the beam and T is the rolling period. This formula is rearranged to solve for GM, substituting the given beam (20 feet) and rolling period (6 seconds) to arrive at the solution.