seventeen longitudinal bulkheads. A double bottom further improved the ships' resistance to damage below the waterline. The hulls were constructed with iron, but their superstructures were largely composed of steel to save weight. Steering was controlled from a small conning tower directly aft of the forward main battery gun. Marceau was fitted with a pair of pole masts equipped with fighting tops that carried some of her light guns and spotted for her main battery. Magenta had a heavy military mast in place of her forward pole mast, and both of Neptunes masts were of the heavy variety. Their crews ranged from 643 to 651 officers and enlisted men. Marceaus propulsion machinery consisted of a pair of compound steam engines that each drove a screw propeller, while Magenta and Neptune had four such engines driving a pair of shafts. Steam was provided by eight coal-burning fire-tube boilers aboard Marceau and Magenta, but Neptune was fitted with twelve of the boilers. In the early 1900s, the ships were modernized with sixteen Niclausse boilers, which were water-tube models. All three ships' boilers were ducted into a single funnel just aft of the conning tower. Their engines were rated to produce for a top speed of . Coal storage amounted to . Armament and armor Their main armament consisted of four Modèle 1881 or Mle 1884, 28-caliber (cal.) guns mounted in individual barbette mounts. One was forward and one aft, both on the centerline, and two were amidships in wing mounts. Marceau received two of each model of the guns, while Neptune carried four Mle 1884 guns and Magenta mounted four of the Mle 1881 weapons. Both versions fired high-explosive shells filled with melinite with a muzzle velocity of . The main guns were supported by a secondary battery of sixteen 30-cal. Mle 1884 guns, all carried in individual pivot mounts in an unarmored gun battery in the hull, eight guns per broadside. They fired high-explosive shells at a muzzle velocity of . For defense against torpedo boats, the ships carried an extensive battery of light guns, though the numbers vary between sources. Gardiner reports a range of three to six guns, nine to eighteen 3-pounder guns, eight to twelve 1-pounder five-barrel Hotchkiss revolving cannon; naval historian Eric Gille gives four to seven 65 mm guns, nine to twelve 47 mm guns, and eight 37 mm guns; naval historian Paul Silverstone says six