 The ships had four Brown @-@ Curtis single @-@ reduction geared steam turbine sets , each of which drove one propeller shaft . They were arranged in three engine rooms . The forward engine room held the two turbines for the wing shafts , the middle compartment housed the turbines for the port inner shaft and the aft engine room contained the turbines for the starboard inner shaft . A cruising turbine was built into the casing of each wing turbine . The turbines were powered by twenty @-@ four Yarrow small @-@ tube boilers equally divided between four boiler rooms . They were designed to produce a total of 144 @,@ 000 shaft horsepower ( 107 @,@ 000 kW ) at a working pressure of 235 psi ( 1 @,@ 620 kPa ) , but achieved more than 151 @,@ 000 shp ( 112 @,@ 601 kW ) during Hood 's trials , when she slightly exceeded her designed speed of 31 knots ( 57 km / h ; 36 mph ) . 
