 Agamemnon displaced 17 @,@ 683 long tons ( 17 @,@ 967 t ) at deep load as built , with a length of 443 feet 6 inches ( 135 @.@ 2 m ) , a beam of 79 feet 6 inches ( 24 @.@ 2 m ) and a draft of 26 feet 9 inches ( 8 @.@ 2 m ) . She was powered by two inverted vertical triple expansion four @-@ cylinder steam engines , which developed a total of 16 @,@ 750 indicated horsepower ( 12 @,@ 490 kW ) and gave a maximum speed of 18 knots ( 33 km / h ; 21 mph ) . 
