Introduction One difficulty in analyzing submarine accidents is that military services, by their very nature, are secretive, especially when it comes to revealing problems or accidents.
Naval forces are often even more secretive, and submarine forces often the most secretive of all.
However, it is no exaggeration to say that the Soviet Union was far more secretive than any other government that ever operated submarines. Good data about Soviet submarine accidents has most often come from U.S. Navy sources than from Soviet sources. Even with the breakup of the Soviet Union, this situation has not changed dramatically. Information about Soviet submarine accidents during the period from the Bolshevik revolution to the start of World War II has been especially hard to come by. These incidents are listed in reverse chronological order, with the most recent incidents shown first.