Gun size during this period increased dramatically, driven principally by the desire to keep up with Italy, which had begun to use massive guns it its latest ironclads. French capital ship design practices were interrupted by the development of the German s; these were coastal defense vessels that were significantly more powerful than the French coastal defense ships that had already been built under the 1872 plans. "Amiral Duperré" and the "Amiral Baudin"s, powerful enough to defeat the "Sachsen"s but significantly larger than previous generations of French ironclads, had too deep a draft to allow them to comfortably operate in the Baltic Sea. As a result, the French designers scaled down the "Amiral Baudin" design, removing its central barbette and reducing their freeboard to lighten them and thus reduce their draft. But instead of retaining the guns of the "Amiral Baudin" class, a larger gun was chosen for the new ships. Curiously, though the "Terrible" design was derived from that of the "Amiral Baudin" class, work on the former began more than two years before the "Amiral Baudin"s were laid down. The class suffered from significant design faults, most significantly the arrangement of the guns; because they were placed on the centerline, they were arranged for fighting on the broadside. But their short belt, which was almost completely submerged under service conditions, did not sufficiently protect them from damage. The ships of the "Terrible" class were long between perpendiculars, with a beam of and a draft of . They displaced and had a relatively low freeboard. Their hulls were divided into eleven or twelve watertight compartments by transverse bulkheads. They were fitted with a pair of pole masts equipped with spotting tops for their main battery guns. The crew consisted of 373 officers and enlisted men. The ships suffered from very poor seakeeping owing to their shallow draft, severely handicapping their usefulness in service. Their propulsion machinery consisted of two compound steam engines, each driving a single screw propeller, with steam provided by twelve coal-burning fire-tube boilers in the first three ships. "Requin" only received ten of the boilers. The ships' boilers were ducted into four small funnels placed in two pairs, side by side, directly astern of the conning tower. All four ships' engines were rated to produce for a top speed of . Their main armament consisted of two guns, one forward and one aft, mounted on the centerline in barbettes.