The comparison starts with the intended light cruiser: a moderately protected, long-ranged ship able to make about 30 knots. The proposed 6,400-ton design carried three-inch magazine protection, one-inch deck and turret armor, and machinery rated at 60,000 shaft horsepower. The completed Leanders reached about 32.5 knots and extended their practical range, but displacement rose to roughly 7,390 tons standard and dimensions increased in every direction. Growth beyond a normal ten-percent tolerance made this more than a minor adjustment to the original requirement. That gap between the desired capability and the actual hull leads into the Amphion redesign.
Notable Point · 12:13-16:20
The Leander baseline and its growth problem
The Leander class delivered more speed and range than its initial concept, but the resulting displacement and dimensional growth pushed the design toward a fresh solution.