Superfiring

Historically, large surface warships were known by the generic label of battleships, with a further distinction between pre-dreadnoughts and dreadnoughts.

An early concern was that the pressure and shock from the higher turret would damage the lower one when firing over the top.

In 1908, United States Navy tests using the monitor USS Florida (BM-9) as the testbed proved that superfiring was safe.

The British Dido-class, which were also light cruisers armed entirely with dual-purpose guns (the 5.25" Mk 1), also had three turrets forward, with two aft.

Examples of non-superfiring designs include but are not limited to the Gangut, Imperatritsa Mariya, and Imperator Nikolai classes of battleships built for the Imperial Russian navy, as well as modern ships such as the Zumwalt-class destroyers.

The two bow gun turrets on one of the first superfiring battleships, the Brazilian Minas Geraes . They are "superfiring" because one has been mounted over the other, and can shoot over its top.
Line drawing of a South Carolina -class battleship, showing superfiring main armament. [ note 1 ]
The Japanese battleship Fuso featured a combination of superfiring and non-superfiring turrets. The placement of the Z-turret (third from the stern) interfered with the steam turbines, requiring it to be raised above the deck.