Submarines do get sunk in the sea.
Voyage to the Bottom of the Sea - 1964 Submarine Sunk Here 1-10 was released on: USA: 16 November 1964
Nobody. The submarine was captured before it was sunk.
The USS Housatonic, sunk by the Confederate submarine CSS Hunley.
Lusitania
Yes
The Lusitania was sunk near Kinsale, Ireland in the Celtic Sea, an area of the Atlantic Ocean south of Ireland. It was sunk on May 7, 1915 by the German submarine U-20.
HMS K13 sunk in a fatal accident during sea trials in early 1917 and was salvaged and recommissioned as HMS K22.
German submarine ;
Frisen
Germany practiced unrestricted submarine warfare.
It sunk in 1942
USS Thresher