 Their propulsion system consisted of a pair of compound steam engines , each driving a single screw propeller , with steam supplied by eight coal @-@ fired , cylindrical fire @-@ tube boilers . The boilers were trunked into two funnels , one in the forward superstructure and the other in the aft superstructure . Ruggiero di Lauria was the fastest member of the class , reaching a top speed of 17 knots ( 31 km / h ; 20 mph ) at 10 @,@ 591 indicated horsepower ( 7 @,@ 898 kW ) . Francesco Morosini and Andrea <unk> had a top speed of around 16 kn ( 30 km / h ; 18 mph ) . The ships could steam for 2 @,@ 800 nautical miles ( 5 @,@ 200 km ; 3 @,@ 200 mi ) at a speed of 10 knots ( 19 km / h ; 12 mph ) . 
