Wikipedia has an article on:

conning tower (plural conning towers)

  1. (nautical) The armoured control tower of an early iron warship from which the ship was navigated in battle
  2. (nautical) A connecting structure between the bridge and pressure hull of a submarine; in larger, modern submarines it contains the captain's cabin and is known as the sail
    • 1918, Edgar Rice Burroughs, The Land That Time Forgot Chapter IV
      I waited until half an hour after Benson had gone on duty, and then I went on deck, passing through the conning-tower where Benson sat, and looking at the compass. It showed that our course was north by west--that is, one point west of north, which was, for our assumed position, about right.