A Ton an Hour - USS Cairo

Coal shoveled into USS Cairo’s fireboxes heated the boilers, whose steam powered the engines and drove the paddle wheel. Without steam, the gunboat could not move and was helpless if attacked, so ironclads kept fires burning and steam pressure built up even when anchored. For hours on end, coal heavers piled coal from storage bunkers into the fire room, and firemen fed the fuel into each boiler’s firebox. When underway, Cairo’s boilers burned a ton of coal an hour.

Vicksburg, Mississippi · United States