Ironclad frigates start taking over the battle fleet's job

HMS Duncan and HMS Gibraltar were being launched in 1859 and 1860, while Bulwark-class ships such as Repulse and Ocean underwent modifications into armored forms. Warrior's success shifted attention toward fast armored frigates built for running fights and individual engagements instead of the old line of battle. An emergent capability could appear to favor smaller ships, then drive them larger as designers added armor, speed, and firepower. Ironclad frigates and battery ironclads consequently became the battle units around which fleets were organized. Their growth blurred the distinction between the former frigate role and the battle line. In this account of changing terminology, the spread of the frigate's capabilities helps explain the declining usefulness of the name and the later prominence of cruiser, destroyer, and battleship labels.