were exceedingly heavy, which required them to be placed low in the ship to reduce top-weight—and produced a dangerous tendency to capsize in heavy seas, amply demonstrated by the loss of and Coles himself with the ship in a gale in 1870. In the 1870s, designers began to experiment with an en barbette type of mounting. The barbette was a fixed armoured enclosure protecting the gun. The barbette could take the form of a circular or elongated ring of armour around the rotating gun mount over which the guns (possibly fitted with a gun shield) fired. The barbette system reduced weight considerably, since the machinery for the rotating gun mount, along with the mount itself, was much lighter than that required for the gun house of a turret. The savings in weight could then be passed on to increase armour protection for the hull, improve coal storage capacity, or to install larger, more powerful engines. In addition, because barbettes were lighter, they could be placed higher in the ship without jeopardizing stability, which improved their ability to be worked in heavy seas that would have otherwise rendered turrets unusable. This also permitted a higher freeboard, which also improved seakeeping. Ironclads equipped with barbettes were referred to as "barbette ships" much like their contemporaries, turret ships and central battery ships, which mounted their heavy guns in turrets or in a central armored battery. Many navies experimented with all three types in the 1870s and 1880s, including the British Admiral-class battleships, the French s, the Italian s, and the German s, all of which employed barbettes to mount their heavy guns. All of these navies also built turret and or central battery ships during the same period, though none had a decisive advantage over the other. The British and the Russian navies experimented with using disappearing guns afloat, including on the British , the Russian monitor Vitse-admiral Popov, and some of the s. They were not deemed particularly successful and were not repeated. In the late 1880s, the debate between barbette or turret mounts was finally settled. The , mounted their guns in barbettes, but the follow-on design, the , adopted a new mounting that combined the benefits of both kinds of mounts. A heavily armoured, rotating gun house was added to the revolving platform, which kept the guns and their crews protected. The gun house was smaller and lighter than the