 Making a ship broader compared to its length was known to reduce its speed, so the innovative technique of water tank tests on models, pioneered by William Froude, was used to finalise a design.This was ten feet wider than "Duillo" and twenty-one feet shorter, the smallest ever ratio of length to breadth in a metal first class warship.Once the outline design was agreed, the detailed architectural design was done by William White and she was laid down at Portsmouth Dockyard on 24 February 1874.