1 The armoured control centre of a major warship after the change from wood to iron and steel from which, originally, the ship was navigated in battle. Later, with the increasing sophistication of weapons and their control, it also became the centre of communications with the guns and torpedoes, and all information, such as radar plots and ranges, is fed into it. It was occupied only in battle; on all other occasions navigation and weapon control was exercised from the bridge.
2 The connecting structure between the bridge and the pressure hull of a submarine. In the oldest submarines it was no more than a trunk with an internal ladder, sealed at both ends by watertight hatches which were closed when the submarine submerged. In modern submarines the conning tower provides space for equipment and the captain's cabin, and is usually known as the ‘sail’.