The ships were intended to reinforce battleships in close action, protect communications on detached service, and remain competitive with foreign first-class cruisers. Their full coal allowance of about 1,600 tons was intended to support roughly thirty days at ten knots or 120 hours at high sustained speed, revealing how endurance shaped a worldwide cruiser. The advertised 21.5-knot top speed differed from the lower 19.75 knots that machinery and fuel could sustain over time. Normal displacement assumed only 800 tons of coal, so the requirement joined global range to practical loading limits. The Cressys were multi-role ships designed to connect fleet support with Britain's shipping and communications network.
Chapter · 17:47-20:26
Why the Royal Navy wanted the Cressy class
White's requirements combine fleet support, detached commerce protection, long coal endurance, and enough fighting power to meet foreign first-class cruisers.