Although heavier and fitted with less indicated horsepower than the Iris class, the Leanders' refined hulls reached their design speed of 16.5 knots. After their rig was removed and their funnels raised, they could make 17 to 18 knots. Twelve boilers supplied two compound engines driving twin shafts, while normal coal stowage of about 725 tons could rise to roughly 1,000 tons. That capacity supported an estimated 11,000-nautical-mile range at ten knots. Their field and boat guns equipped landing parties, since a foreign-station cruiser had to project force ashore as well as patrol at sea.
Chapter · 9:40-13:45
Machinery traded horsepower for exceptional cruising range
Refined hulls, substantial coal capacity, and compound machinery gave the heavier Leanders far more range than the Iris class.