Soldiers of the Group 13 special forces unit of the Defence Intelligence of Ukraine destroyed the guided-missile corvette Ivanovets, part of Russia’s Black Sea Fleet, on the night of 31 January-1 February 2024.
Source: Defence Intelligence of Ukraine (DIU)
Quote: "The operation was made possible with the support of the Ministry of Digital Transformation of Ukraine and the United24 platform.
The enemy vessel was on the roadstead of Lake Donuzlav in temporarily occupied Crimea.
As a result of a number of direct strikes to the hull, the Russian vessel sustained critical damage causing immobilisation – it heaved aft and sank."
The force of that main explosion I would think killed instantly or disabled everyone on board.