 The ships were powered by two vertical triple-expansion steam engines, each driving one propeller, using steam generated by 14 cylindrical boilers at a working pressure of 8.8 atm (892 kPa; 129 psi). Unlike her sisters, Sevastopol had 16 boilers. The engines were rated at 10,600 indicated horsepower (7,900 kW) and designed to reach a top speed of 16 knots. The machinery for Poltava and Petropavlovsk was ordered from British companies and slightly exceeded their specifications; the ships reached maximum speed of 16.29 and 16.38 knots (30.17 and 30.34 km / h; 18.75 and 18.85 mph) from 11,213 and 11,255 indicated horsepower (8,362 and 8,393 kW), respectively, during their sea trials. Sevastopol, using domestically built machinery, only reached a speed of 15.3 knots (28.3 km / h; 17.6 mph) from 9,368 indicated horsepower (6,986 kW), despite the extra boilers, but the Naval Ministry chose not to exercise the penalty provisions of the contract for failing to attain the design speed because it had specified the machinery to be used. They carried a maximum of 1,050 long tons (1,070 t) of coal which allowed them to steam for 3,750 nautical miles (6,940 km; 4,320 mi) at a speed of 10 knots (19 km / h; 12 mph).
