You are on a vessel that has a metacentric height of 1.0 foot and a beam of 40 feet. What can you expect the rolling period of the vessel to be?
• Metacentric height (GM) and how it affects a ship’s rolling period • The approximate rolling period formula using beam and GM • The effect of a larger GM on stiffness and roll speed
• Recall the empirical formula that relates rolling period to beam and GM; identify which quantities you are given and how they fit into that formula. • Think about whether a vessel with GM = 1.0 ft and B = 40 ft would have a relatively short, snappy roll or a long, slow roll. • Estimate the roll period using the standard constant used in the formula, then compare your estimate to the choices given.
• Make sure you are using beam (B) in feet and GM in feet in the same system of units. • Confirm that you are using the correct constant in the rolling‑period formula used on U.S. license exams. • After calculating, check that your result is close to one of the options and that the trend (stiff vs tender) makes physical sense.
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