The Admiral Lazarev class was a pair of monitors built for the Imperial Russian Navy in the late 1860s (designated frigates by the navy). Four ships were ordered, but the last two were significantly modified and became the separate Admiral Spiridov class of ships. Admiral Lazarev and Admiral Greig became the first turreted warships in the Russian Navy.
The ships were similar in size to earlier Russian ironclads. They had a shorter beam due to the turret, rather than broadside weaponry. A longer draft made the ships more stable at the sea. Due to the heavy weight, the masts of the ships were significantly lighter and smaller than initially planned, but the more powerful 2,000 horsepower (1,500 kW) engine made the ships somewhat faster than earlier monitors, with the top speed of 11 knots (20 km/h).
The ships were protected by a 4.5 in (114 mm) armor belt and turrets by 6.5 in (165 mm) armor. The main armament was three gun turrets, each with two 9-inch (229 mm) guns. Later, all four ships had turrets refitted with 11-inch (279 mm) guns, one gun per turret. With the new guns, the Admiral Lazarev and Admiral Spiridov classes became among the most powerful ships of the Baltic Fleet.
