What is "clads"

Usage examples of "clads".

Then a cannon on one of the armor clads thundered, and a shell ripped its way through the underbrush on the west bank.

The fleet, the armor clads, the floating batteries, and the mortar boats, were coming straight toward the fort.

Don't tell me about the success of Allied ironclads against the Russians in the Crimea1 read McClellan's report from there, but I assure you our placed guns could destroy a flotilla with ease.