Probably against the rules to use iron-clad as well. The first warship to be iron clad was used in the US civil war by the confederacy. https://en.m.wikipedia.

Probably against the rules to use iron-clad as well. The first warship to be iron clad was used in the US civil war by the confederacy. https://en.m.wikipedia.org/wiki/Ironclad_warship https://en.m.wikipedia.org/wiki/Ironclad_warship