Cottonclads were a classification of steam-powered warship

Warship

A warship is a ship that is built and primarily intended for combat. Warships are usually built in a completely different way from merchant ships. As well as being armed, warships are designed to withstand damage and are usually faster and more maneuvrable than merchant ships...

s where a wooden ship was protected from enemy fire by bales of cotton

Cotton

Cotton is a soft, fluffy staple fiber that grows in a boll, or protective capsule, around the seeds of cotton plants of the genus Gossypium. The fiber is almost pure cellulose. The botanical purpose of cotton fiber is to aid in seed dispersal....

 lining its sides. This provided some protection from enemy fire, but not to the extent of ironclads. Cotton-clads were prevalent during the American Civil War

American Civil War

The American Civil War was a civil war fought in the United States of America. In response to the election of Abraham Lincoln as President of the United States, 11 southern slave states declared their secession from the United States and formed the Confederate States of America ; the other 25...

, particularly in the Confederate States Navy

Confederate States Navy

The Confederate States Navy was the naval branch of the Confederate States armed forces established by an act of the Confederate Congress on February 21, 1861. It was responsible for Confederate naval operations during the American Civil War...

for riverine service.

The heavy bales of cotton slowed small arms fire, but at times the cotton would catch fire from artillery shells.