George Wallace Melville was an American engineer, Arctic explorer, and author. As chief of the Bureau of Steam Engineering, he headed a time of great expansion, technological progress and change, often in defiance of the conservative element of the Navy hierarchy. He superintended the design of 120 ships and introduced the water-tube boiler, the triple-screw propulsion system, vertical engines, the floating repair ship, and the "distilling ship." Appointed engineer in chief of the Navy, Melville reformed the service entirely, putting Navy engineers on a professional rather than an artisan footing.