Composite armor worked by managing impact and splinters

Which material combinations worked or failed as naval composite armor?

Layered iron, steel, and timber could manage impact and splinters effectively, while unsuitable alloys such as salt-water-vulnerable aluminum created serious durability problems.

Some Soviet gunboats used aluminum alloys that corroded badly in salt water, but earlier composite armor pursued a different and often successful purpose. Iron-and-steel or iron-and-timber layers combined a hard striking face with backing that distributed energy and limited splinters inside the ship. HMS Warrior's surviving armor section demonstrates the enormous thickness required by this approach. That protection, combined with speed, guns, crew, and seakeeping, made her vastly more capable than USS Monitor outside a contrived confined-water scenario. The comparison shows that material combinations must be judged by environment, failure mode, and the complete ship rather than by novelty alone.