MOSCOW, 21 Sep-RIA Novosti, Sergey Safronov. Submarines of the Varshavyanka type (projects 877 and 636) began to be called "black holes" because of the appearance of a new main rowing electric motor, from which the submarines became almost silent, Andrei Baranov, deputy General Director of the Central Design Bureau of Marine Technology (CCB MT) "Rubin", said in an interview with RIA Novosti.
He also noted that the power plant was further improved due to more powerful diesel generators. This replacement required a slight increase in the length of the boats, but as a result, the battery charging time was reduced, that is, again, the stealth increased. There were more capacious batteries-the range of navigation and the time spent by the boats in the underwater position increased. Then a digital sonar system was introduced, which strengthened the search potential.