 Her eventual cost was £812,000.To counter the perceived threat from the Italians, "Inflexible" was to be equipped with four of the largest guns available, weighing 60 tons each.In October 1874 it was decided to modify the design of "Inflexible" to use an even bigger gun which Armstrongs was producing, a 16-inch (406 mm) gun weighing 81 tons.