 To save design time , the four @-@ shaft unit machinery from the Lion @-@ class battleship was duplicated with alternating boiler and engine rooms . Vanguard had four sets of single @-@ reduction geared Parsons steam turbines housed in separate engine rooms . Each set consisted of one high @-@ pressure and one low @-@ pressure turbine , driving a propeller that was 14 feet 9 inches ( 4 @.@ 5 m ) in diameter . The turbines were powered by eight Admiralty 3 @-@ drum boilers in four boiler rooms at a working pressure of 350 psi ( 2 @,@ 413 kPa ; 25 kgf / cm2 ) and temperature of 700 ° F ( 371 ° C ) . The engines were designed to produce a total of 130 @,@ 000 shaft horsepower ( 97 @,@ 000 kW ) and a speed of 30 knots ( 56 km / h ; 35 mph ) , but achieved more than 136 @,@ 000 shp ( 101 @,@ 000 kW ) during the ship 's sea trials in July 1946 , when she reached a speed of 31 @.@ 57 knots ( 58 @.@ 47 km / h ; 36 @.@ 33 mph ) . After trials , the three @-@ bladed propellers on the inboard shafts were replaced by five @-@ bladed propellers in an unsuccessful attempt to reduce vibrations of the inboard propeller shafts . 
