The Tug SB-921 Evgeniy Churov The Tug SB-921 Evgeniy Churov The SB-921 Evgeniy Churov  is a Sliva-class (Project 712) ocean-going tug of the Russian Navy, designed to provide at-sea logistical and rescue support. It has frequently been observed escorting Russian submarines, including Kilo-class diesel-electric submarines (SSKs) such as the Krasnodar  and Novorossiysk . Its presence in the Mediterranean, as reported in recent updates, may indicate a support role for Russian na