Question 3641 Deck General

The correct answer is C) during fire drill. Watertight doors on a Mobile Offshore Drilling Unit (MODU) should be operated during fire drills to ensure they are functioning properly and can effectively contain a fire. This is in accordance with Coast Guard regulations, which require regular testing and operation of watertight doors to maintain the structural integrity and safety of the vessel. The other answer choices are incorrect because: A) Watertight doors are not specifically required to be operated during abandon ship drills. B) Watertight doors should be operated during normal operations, not just when the rig is being moved. D) Weekly operation of watertight doors is not a regulatory requirement, as they should be tested and exercised during fire drills and other routine safety checks.