Question 3758 Deck General

The correct answer is D) Storage plans. After a report of casualty to a Mobile Offshore Drilling Unit (MODU), the storage plans must be retained on board. This is because the storage plans contain critical information about the MODU's cargo, fuel, and other essential systems, which may be relevant for investigating the cause of the casualty. The other options, such as the preventive maintenance log, oil record book, and repair record book, while important for the general operation of the MODU, are not specifically required to be retained on board after a casualty report. The storage plans, on the other hand, are a crucial document that must be available for any subsequent investigation or analysis related to the incident.