 Aretusa was 73 @.@ 1 meters ( 239 ft 10 in ) long overall and had a beam of 8 @.@ 22 m ( 27 ft 0 in ) and an average draft of 3 @.@ 48 m ( 11 ft 5 in ) . She displaced <unk> metric tons ( 820 long tons ; 918 short tons ) normally . Her propulsion system consisted of a pair of horizontal triple @-@ expansion steam engines , each driving a single screw propeller , with steam supplied by four coal @-@ fired <unk> boilers . Specific figures for Aretusa 's engine performance have not survived , but the ships of her class had top speeds of 18 @.@ 1 to 20 @.@ 8 knots ( 33 @.@ 5 to 38 @.@ 5 km / h ; 20 @.@ 8 to 23 @.@ 9 mph ) at 3 @,@ <unk> to 4 @,@ 422 indicated horsepower ( 2 @,@ <unk> to 3 @,@ <unk> kW ) . The ship had a cruising radius of about 1 @,@ 800 nautical miles ( 3 @,@ 300 km ; 2 @,@ 100 mi ) at a speed of 10 knots ( 19 km / h ; 12 mph ) . She had a crew of between 96 and 121 . 
