K-19 was the first submarine of the Project 658 class, the first generation of Soviet nuclear submarines equipped with nuclear ballistic missiles, specifically the R-13 SLBM. The boat was hastily built by the Soviets in response to United States' developments in nuclear submarines as part of the arms race. Before she was launched, 10 civilian workers and a sailor died due to accidents and fires. After K-19 was commissioned, the boat had multiple breakdowns and accidents, several of which threatened to sink the submarine.

A submarine is a watercraft capable of independent operation underwater. It differs from a submersible, which has more limited underwater capability. The term is also sometimes used historically or colloquially to refer to remotely operated vehicles and robots, as well as medium-sized or smaller vessels, such as the midget submarine and the wet sub. Submarines are referred to as boats rather than ships irrespective of their size.