When must the Master or person in charge of a MODU log the position of load line marks in relation to the surface of the water in the logbook?

Correct Answer: Option D — Prior to getting underway

46 CFR requires the Master or person in charge to verify the vessel's draft and ensure the load line marks are not submerged beyond the permitted limits prior to getting underway. This ensures the vessel is in compliance with stability and freeboard requirements before entering open water or restricted channels.