Historical Trivia: Up Periscope
The Royal Navy led the world in the development and deployment of submarines during the early 20th century with the development of the Holland boats and later the A1 class. The A1 can be seen as the first submarine to have the features which are instantly recognisable today.
This was thanks to Captain Reginald Bacon who was instrumental in including some revolutionary features on the new A1 class submarine, he devised one of the first modern periscopes as well as the concept of a conning tower for when running on the surface.
Previous to this Holland's submarine has had an almost flush deck and had used a crude viewing mast for steering while submerged, Admiral Jackie Fisher described Bacon as "the cleverest officer in the Navy", and without him submarines may not have been the same.