Delfin (Project 667BDRM (Delta IV))

The Project 667BDRM Delfin (Delta IV) is a class of nuclear-powered ballistic missile submarines (SSBNs) developed in the Soviet Union. These submarines are a key component of Russia's strategic nuclear forces, armed with R-29RMU Sineva or R-29RMU2 Layner SLBMs.

Designed by the Rubin Design Bureau in the late 1970s, the Project 667BDRM was developed to counter Western acoustic detection capabilities by incorporating advanced noise-reduction technologies and a more streamlined hull. The lead vessel, K-51 Verkhoturye, was commissioned into the Soviet Northern Fleet in December 1984, with a total of seven submarines constructed through 1990. Throughout their service, these submarines conducted vital under-ice patrols in the Arctic, notably achieving a historic milestone in 1991 when K-407 Novomoskovsk successfully launched a full salvo of 16 ballistic missiles during Operation Behemoth-2. Today, several modernized units remain active in the Russian Navy, serving as a reliable cornerstone of the sea-based nuclear triad while being gradually succeeded by the newer Borei-class.