When is the density of the water required to be logged in the logbook of a MODU?

Correct Answer: Option D — Prior to getting underway when the vessel is floating in fresh or brackish water

Per 46 CFR 109.431, the Master must log the density of water prior to getting underway when the unit is floating in fresh or brackish water. This ensures accurate calculation of the vessel's draft and stability, as the buoyancy characteristics change significantly compared to salt water.