Fire Tube Boilers and the Civil War
During my vacation this year with the family, we were traveling through the old south, and made a stop at the Vicksburg National Military Park in Vicksburg, Mississippi. This park is amazing memorial to both Union and Confederate armies that had fought and died in the Civil War. Many of the 48,000 that had died at the Siege of Vicksburg are buried at the military cemetery there on the grounds.
President Abraham Lincoln said that Vicksburg, at the time a Confederate fortress and stronghold, was the key to victory because of its strategic location on the Mississippi River. Without the free flow of trade to the south, agricultural products from the north could not reach the Gulf and have access to vital world markets.
One of the highlights at the Park is a museum dedicated to the USS Cairo, a Civil War ironclad gunboat that was sunk in 1862. It was found almost 100 years later, and eventually raised in 1966, cleaned and partially restored. Its artifacts are part of the museum’s display that tells the lives of the sailors who called this ship home.
Of interest as an EHS professional was the USS Cairo's five fire tube boilers. These are among the oldest examples of this type of boiler. According to the boiler’s specifications, they operated at 140 pounds per square inch steam pressure and consumed almost a ton of coal per hour. That burning coal from the Cairo as well from her sister ships, would have released tons of pollutants to the air, making the air during the battle’s toxic to breathe.
The fire-tube boilers are a type of boiler are simple in design where the hot gases pass from the fire through one or more tubes running through a sealed container of water. The heat is transferred through the walls of the tubes, then that heat the water and create the steam. That steam is then used to power the vessel, a Civil War technology that is still seen today in natural gas fired fire tube industrial boilers.
What was interesting about it’s sinking was that it was the first time an electric charge was used to detonate torpedoes that ultimately destroyed the Cairo. Witnesses said it took 12 minutes to sink to the bottom of the river (~36 feet) after a torpedo exploded under the starboard bow. There was no loss of life, and crew members were able to be rescued by nearby vessels.
Our visit was a great experience, touring the battlefields, cemetery and walking through the USS Cairo. A very reverent place that reminds us of the sacrifices made for freedom. If you’re ever in the area, it’s well worth the stop to see this important piece of our American history.