To register a berth in a Port, open the drawer for the given Port Call by clicking it in the list. Then click the icon at the top of the drawer and select "Register Berth". A dialog will open, allowing you to enter the berth date and the remaining quantity of bunkers on board upon berthing. The bunker categories listed here are only those that were used during the voyage.
If registered date is in the past, the berthed date will be locked. Registered ROBs will be locked as Berth ROBs.