When aluminum became practical for ships

When did ship designers begin considering aluminum?

They considered it early because it was light, but quantity, cost, purity, and alloy quality kept it from becoming broadly practical until the twentieth century.

Designers became interested in aluminum almost as soon as they understood its low weight. The obstacle was producing enough metal at acceptable purity and cost, since aluminum remained exceptionally expensive in the nineteenth century. By the 1920s industry could obtain more practical quantities, although the available alloys still were not considered good armor. Interest in lighter ships, possible cruise-liner applications in the late 1930s, and aircraft construction followed. Recycling offered another advantage because recovering aluminum was cheaper than extracting new metal from bauxite.