conning tower       
noun [ C ] uk/ˈkɒn.ɪŋ ˌtaʊ.ər/ us/ˈkɑː.nɪŋ ˌtaʊ.ɚ/
 (潜水艇或旧时军舰的)指挥塔,司令塔
a structure on top of a submarine (= a ship that can travel underwater) or, in the past, a military ship, from which the ship can be controlled and that contains a periscope (= a device for seeing what is above you)
  The conning tower of the sub slowly emerged from the water. 潜艇的指挥塔慢慢浮出水面。 
 - More examples
 - I could clearly make out the shape of the submarine with its conning tower.
 - The only entrance to the submersible was a sixteen-inch hatch in the conning tower.
 - The torpedo hit at the base of the conning tower.
 - They lowered a rope ladder from the conning tower.