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by petre 1350 days ago
It has been possible since WWII, only not from tens of miles:

"During the early months of the Battle of the Atlantic in World War II, British ships using the radar set Model 271 were able to detect the periscope of a submerged submarine at a distance of 800 m (0.50 mi) during tests in 1940."

https://en.m.wikipedia.org/wiki/Submarine_snorkel