Watch FMovies. In November 2017 in Volgograd, the BK-31 armored boat was raised from the bottom of the river. According to historical data, from July 1942 until the month of October, the ship took an active part in the Battle of Stalingrad. Built at the special request of the NKVD "BK-31" at that time was a ship unique to the river fleet. After getting up on board, artifacts, the remains of the team, various weapons and a huge amount of ammunition were discovered on it, the latter indirectly confirms the historians' version of the “special” tasks that the navy had to carry out.