Quarterdeck

[1] In the 20th century the word came to be applied to the area at the stern of the ship, often (on naval vessels) used for secondary weapons and (on battleships) seaplane catapults.

In modern military designs the stern has been roofed over by the helicopter deck but a large space remains underneath which is typically used for sonar equipment or small boats and which is still referred to as the quarterdeck in Commonwealth navies.

This continued into Christian times,[2] and in medieval British warships, the religious shrine was set up on the quarterdeck.

[2] In port, the quarterdeck is the most important place on the ship, and is the central control point for all its major activities, as well as it is where the captain usually stands.

Smoking and recreational activities are prohibited on the quarterdeck unless specially authorised by the commanding officer.

[4] In medieval times, warships had a single deck, with raised structures at each end: the "forecastle" in the front, and the "aftercastle" in the rear.

[3] By extension, on flush-decked ships the after part of the main deck, where the officers took their station, was also known as the quarterdeck.

Raised quarterdeck of an 18th-century frigate, between the main mast and the even higher poop deck at the stern.
Before helicopter decks became common, warships such as the Rothesay class often had a deck at the stern used for secondary armament.
Seaplanes were often operated from the quarterdeck of battleships, as here on USS Colorado
A model of the richly decorated stern and quarterdeck of Vasa , a sailing warship built in the late 1620s
Quarterdeck of a Japanese warship. Note the watchstanders in uniform, the wooden plaque, and the proximity to the accommodation ladder.