Arkansas's protection combined railroad iron with wood and compressed cotton rather than purpose-made naval armour. The pilot house carried two inches of railroad iron, the casemate roof only half an inch, and the stern relied on thin iron sheets. The result was more iron-skinned than fully ironclad. Rail iron was made for durability in track service rather than resisting projectile impact, so nominal thickness did not provide the performance of proper armour plate.
Notable Point · 13:24-14:28
Railroad iron gives Arkansas improvised protection
Railroad iron laid over timber and compressed cotton produces uneven protection made from material intended for durability rather than shell impact.