The Russian boat Yaroslavets (project 376) appeared in the fifties of the twentieth century. For the needs of the navy and the national economy, a project for a tugboat was required, which would be used for diving and customs work. That is why in 1948 the project of the boat was approved, which received the number 376 and the code "Sever". It was supposed to be used by the fleet and some spheres of the national economy. When designing the ship, a necessary condition was put forward: Russian-made boats must have all the necessary characteristics for transporting ships by rail.

In 1953 launched the lead boat of Project 376. The ships were immediately put into production in a large series. And two years later, some of the project data were changed, which made it possible to improve the operational characteristics of the vessel and modernize its production technology. A new Yaroslavets appeared - a project 376U boat. After the changes were made, this was actively used not only by the military, but also by civilian ministries and departments, as well as for supplies abroad.

Project R376 - a boat, which is a motor ship with one propeller, with a saddle deck, a wheelhouse with a superstructure, with a canopy over the engine room and aft hold compartment. The hull of the ship is usually made with a solid transverse seam. The boat is equipped with six watertight bulkheads, three fuel tanks are installed on the bottom of the vessel.

Yaroslavets series are designed in such a way that their operation would reduce the time for transporting divers or cargo to their destination and ensure uninterrupted operation in water bodies, rivers or lakes. A harbor boat or a towing boat is built in such a way that water maneuvers can be easily performed in shallow water, as well as in shallow ice surfaces. To perform operations in reservoirs where there is fine broken ice, the ice kingston is provided in the design of the boat.

Boat RK-621 commissioned on 1975 and was assigned to the Black Sea Fleet.

Now in service.