Ok, now I am going to ask the stupidest submarine question.
Good thing I am a landlubber so I can have some excuse.
Given all the technology we have these days, why are not modern submarines constructed without sails?
Everything could be in a very streamlined "whale" shape. Now that Periscopes do not need a direct optical path as they are more sensors than a periscope, why is there still a need for a sail on a submarine?
What is the use of the sail on a modern nuclear submarine that spends 99% of its time underwater tryin to be sneaky?