Project 1710 Макрель (NATO reporting name "Beluga") was a Russian SSA diesel-electric submarine. It was an experimental vessel used for testing propulsion systems, hull forms, and boundary-layer control techniques. Development was undertaken by the Malakhit Design Bureau with construction at the Admiralty shipyard in St. Petersburg. The lone Beluga class submarine in operation was the S-553 Forel. Launched in 1986 and moth-balled around 1998, the last operation of the vessel is thought to have taken place in 1997. As of the mid-2000s, the entire project is believed to have been discontinued.