 The Izumo @-@ class ships were equipped with four submerged 18 @-@ inch ( 457 mm ) torpedo tubes , two on each broadside . The Type 30 torpedo had a 100 @-@ kilogram ( 220 lb ) warhead and three range / speed settings : 870 yards ( 800 m ) at 27 knots ( 50 km / h ; 31 mph ) , 1 @,@ 100 yards ( 1 @,@ 000 m ) at 23 @.@ 6 knots ( 43 @.@ 7 km / h ; 27 @.@ 2 mph ) or 3 @,@ 300 yards ( 3 @,@ 000 m ) at 14 @.@ 2 knots ( 26 @.@ 3 km / h ; 16 @.@ 3 mph ) . 
