Shore batteries could exceed the 16.5-inch naval gun limit

Could coastal batteries break the practical 16.5-inch limit on naval gun size?

Potentially, because a fixed battery avoids several shipboard penalties, although the larger gun would remain expensive and slow-firing.

The practical limit around 16 to 16.5 inches comes largely from the rate of fire achievable aboard a moving battleship. A fixed coastal battery avoids ship motion and faces fewer weight and space penalties. Those advantages could make a larger weapon more efficient in a shore emplacement even when it would be unattractive at sea. The installation would still be expensive, and political authorities would have to fund the specialized works. Fixed mounting changes the engineering balance without removing the loading problem altogether.