A periscope.
A standard viewing device used on a submarine is a periscope.
Ballast tank
scope
Submarines don't have windows, at least not any that are used for viewing outside of the hull while submerged. They are used in some submarines as bridge viewing windows, but they're subjected to ambient sea pressure when the boat submerges, not direct sea pressure like the hull is.
ASDIC
Sonar is used to detect other vessels or ships/submarines through a tube-like device> Andrea
That would be scope.
That would be scope.
That would be scope.
Zoetrope
This sounds like it's probably the sonar system of a submarine.
A spectrometer is a device that is useful for viewing a spectrum of light. It allows for the measurement and analysis of different wavelengths of light within the spectrum, providing valuable information about the composition and properties of the light source.