Several important technological advances had become available by this time, however, which necessitated several changes to the design. The advent of smokeless powder permitted smaller guns with greater muzzle velocities; the Navy had accordingly designed a 12-inch (305 mm) 40-caliber high-velocity gun. In addition, Krupp cemented armor had been developed in Germany; the steel was a significant improvement over the older Harvey process. Since the steel was stronger, thinner armor plating could achieve the same level of protection and more importantly, significant savings in weight. Water-tube boilers were also now sufficiently reliable for use in warships. These were lighter and substantially more efficient than older fire-tube boilers.