Weeks into its inaugural season, Portland’s deep-water berth proved to be not quite deep enough. The Caribbean Princess left abruptly Sept. 27 — surprising some of its passengers ashore — to ride out an astronomical low tide in deeper water. The ship, which draws 27 feet, could have been left less than a foot from the bottom, which is not enough clearance for comfort.

People looking for a scandal were quick to point to the designers of the new facility, who shifted the “megaberth” into a shallower area of the harbor than had originally been planned. But before people get too worked up, there are a few aspects of this story to remember.

The first is that the tide was unusually low, and for most ships at most times, there is plenty of room to tie up at the new berth. What happened last week was not unique to Portland, and ships will not be shunning the port as a result. And no one was abandoned in Portland. The passengers who were not on board when the ship left the dock were ferried out, and all were accounted for when the ship left the harbor on time later that evening.

The main concern is that the federal shipping channel in Portland is overdue to be dredged, and that has an impact on the whole harbor. Due to the motor oil, gasoline and other contaminants that run off Portland’s streets with every rain and settle on the bottom of the harbor, dredging spoils are costly to get rid of.

It will require expensive testing and a more expensive disposal plan for this necessary project to be completed. But if the Caribbean Princess experience becomes the norm instead of the exception, then the cost of dredging Portland Harbor will be eclipsed by the cost of not dredging.