While in ocean transit, the COASTAL DRILLER has a roll period of 9 seconds. What is the largest angle each side of vertical that does not exceed the design limits of the legs in good weather?

Correct Answer: Option D — 7°

Ocean transit dynamic stress limitations for mobile offshore drilling units dictate maximum allowable amplitudes of motion. With a 9-second roll period in favorable weather conditions, the maximum angular displacement each side of vertical to protect leg structural design limits is restricted to 7 degrees.