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84th GM Presentation Jennings

Print Date: 7/19/2024 4:33:05 PM

The 84th General Meeting Featured Presentation
Patrick Jennings

What Happened to the Sultana?

The following presentation was delivered at the 84th General Meeting Monday afternoon session, April 27. It has been edited for content and phrasing.


2015 marks the 150th anniversary of the explosion of the Sultana. The explosion of boilers on the Sultana resulted in the deaths of over 1,800 persons, most of whom were Union soldiers returning home at the end of the Civil War. Hartford Steam Boiler's Patrick Jennings is a principal engineer with a primary focus on boilers and related technology. He is also an expert on the Sultana. As a member of the engineering and standards team, he works with underwriting and claims to support the insurance operations. Additionally, he provides technical support to inservice inspection. Mr. Jennings has 28 years of experience in the industry. He sits on the ASME Section 1 Subgroup for Solar Boilers and contributes to other boiler and pressure vessel subgroups and committees. With a B.S. in mechanical engineering, he has authored 14 technical papers and has one patent. He also maintains a National Board inservice commission.

Mr. Jennings' slide presentation can be accessed here.


On April 27th, 1865, 150 years ago, the steamboat Sultana left the wharfs at Memphis, Tennessee, and started north. They picked up some coal about seven miles north of Memphis. It was two o'clock in the morning when three of the four boilers exploded. Samuel Clemens, not the famous author, but the engineer that was in charge of the boilers at the time, was severely scalded. He survived long enough to get back to shore. He gave testimony to the first investigators, and then he perished.

There is a woman whose name will be forever lost. She was a member of the Christian Commission, which was a precursor to the American Red Cross, and she calmed men that were hanging onto the ropes and chains at the front of the boat. She calmed them and prevented them from panicking and killing one another and pulling one another down. As the flames approached her, she was afraid that she was going to panic them. They said, “Jump in, jump in,” and she said, “No, I will not panic you and cause others to die.” She actually stepped back into the flames as a martyr. Obviously she didn't make it.

Joseph Test was killed when a piece of timber from the wood pierced him, and we know about Joseph because of his friend, who had a most unusual survival story. His friend couldn't find any wood to use as a life raft, so he went to the very front of the boat where the pet mascot was kept, an alligator. They say he stabbed the alligator three times, pulled it out of the crate, and used the crate as his life raft. He survived.

Overall, over 1,700 or 1,800 -- nobody knows the exact number -- people died that night, and it was the worst maritime disaster in United States history. And yet very few people have ever heard of it. Most people on the boat were soldiers returning from the Confederate prisons of Cahaba and Andersonville. These men were starved. Some of them weighed 100 pounds. And if you could see the pictures of them, they look like Holocaust survivors. There were 2,400 men, women, and children that were stuffed on this boat. The boat was designed for 376 people. So the question is why did this happen? And the simple answer is greed and corruption.

The Union paid the boat owners five dollars per enlisted man and 10 dollars for every officer that was on the boat. Captain J. Cass Mason had a small ownership in the Sultana. There is evidence that on his way down river, he procured bribes to allow that when he came back up river, he could pick up a lot of passengers. Two boats left the wharfs empty that day. His boat had 2,400 people on it.

Captain Mason wasn't held accountable because he didn't survive the night. Captain Frederick Speed, an Army quarter-master, was charged and court-martialed, but later his court-martial was overturned. At the end of the day, nobody was held accountable. This disaster was forgotten, because at the time, President Lincoln was shot the same month. Lee had just surrendered to Grant, effectively ending the war. And the day before, John Wilkes Booth had been murdered or killed. So a country that was tired of death, a country that was tired of destruction in the war, forgot about this.

Luckily for us, two people didn't forget. Jeremiah Allen and Edward Reed became the founding members of Hartford Steam Boiler. Hartford Steam Boiler is very tied to his event, and when the documentary was formed, we became the corporate sponsor. And as the engineer for boilers with Hartford Steam Boiler, I was asked to look into this. I thought it would be pretty simple. I read articles and I agreed with the theories of why it happened, but I was wrong.

The most common theory that goes toward the explosion of the Sultana is the careening theory. According to this theory, the boilers were low on water, and as the Sultana rocked side to side, the bottom of the boiler would overheat and grow red hot, and when it rocked back to the other direction, the red-hot iron would be covered in water and it would create a lot of steam. They were right, there was a lot of steam generation in the boiler explosion, but I don't think this is right. The reason many people believed this is because it was discussed extensively and exclusively in the testimony by the people.

The chief engineers and scientists of the day, J.J. Witzig, Isaac West, W.B. Richardson, and Chief Engineer Wintringer all discussed careening in their testimony. They discussed careening extensively at the trial of Captain Frederick Speed. Three of these people weren't on the boat at the time. The fourth, Chief Engineer Wintringer, was asleep. None of the people who were on the boat and awake at the time mentioned that the boat was careening. They used terms like peace and quiet. One of the guys said that it was very peaceful and quiet before his canteen was blown out of his hands. General Hoffman, one of the three investigators, in a letter to the Secretary of War said, “There is nothing to show that there was any careening of the boat at the time of the disaster.”

There are other theories. There is testimony by J.J. Witzig, the chief inspector for St. Louis, and he said that it was a quarter-inch iron that was used for the patch -- and I will talk about the patch -- and he said according to his calculations, this meant that the maximum allowable working pressure was 100 psi. I did the calculation, and, in fact, he's pretty close. But we all know that there is a safety factor, and that the burst pressure of that patch would have been a lot higher.

There was a lot of talk about sabotage. There were people who were really adamant that sabotage caused the explosion of the Sultana. The Confederates did have a device called a coal torpedo. There was casting metal that held about four ounces of powder, and they would be covered in coal dust and then thrown into the coal bins, and the intent was that when they got shoveled in and were underneath the boiler, it would cause an explosion. There was a shell found in the wreckage, but it was not a coal torpedo. And there was a report of a confession, too. There was no physical evidence and no corroborating evidence that it was sabotaged. So I was really interested in understanding what it was that caused the explosion and why there was discrepancy in the careening theory.

I found some testimony from both Captain Frederick Speed and the investigators. There are hundreds of pages, and I only had to read about 40 pages because I knew the people that I wanted to talk about, and one of them was R.G. Taylor, who was a boilermaker. He was hired to repair the boiler in Vicksburg, Mississippi, on its way upriver right as they were loading passengers. When he gave his testimony, when he was asked about the boiler sheets, he said, “Yes, there was a leak in the sheets.”

The boiler sheets on either side were in very bad shape. They were burnt. He said he did not do the repair. He did a bigger repair. He was asked if this incomplete repair could have caused the damage, and here was his answer: “Yes, it did.” And this is interesting: “As long as there is a sufficiency of water in the boiler, there is no danger of an explosion.” We now know that that is not the case, and that the more water in the boiler, the more likely an explosion or how big it would be.

I started looking at other people. Of the four experts who gave testimony, there are other examples where it appears they didn't understand. Isaac West talks about the patch only would have blown off and the injury would have stopped there. Well, we know that that statement is wrong because of the water in the boiler. That makes you wonder what did they know or not know about boiler explosions? I started looking through Google Books, and I actually fell in love with it. There are a lot of texts from the 1800s. I found about six textbooks from boilers and boiler explosions and boiler theory. There are three that we are going to use the most. The first one is called Steam-Boiler Explosions, and it's by Robert Henry Thurston. And I didn't know who he was, so I looked him up, and I should have known who he was. He was the first president of ASME, and he seemed like a rock star to me. Here’s a guy who is going to tell me all about steam-boiler explosions.

The second book referenced was by William Barr and he talked a lot about the types of irons that were used in the construction of boilers at the time. The third book I used was by George Bates Nichols Tower, Useful Things to Know about Steam Boilers. This book was similar to an operator's or owner's manual. It contained really good information, and it corroborated the information from the first two books, although it wasn't quite as detailed as the first two.

A table from Robert Thurston's book shows a lot of work in the 1830s by the Franklin Institute to test really small boilers. The first steam studies where they looked at the efficiencies and the detector of steam were done in the 1860s, and some of you may recognize the name Rankine. They found there was a huge amount of energy that's stored in a boiler, and almost all of it, 97 percent, stored in the form of water and not in steam. In 1865 they believed that most of the energy was in steam and not the water, but by the late 1800s, the books said that was all wrong. The amount of steam is incredible.  

When a tubular boiler full of water explodes, there is enough energy to raise that boiler almost a mile high. Now, after Thurston had looked at this information -- and this is a key thing that he found -- he talks about low water and the careening of the boiler, and he said some authorities now question the possibility of its action at all. We went from 1865 when everybody said all boilers exploded because of low water, to 20 years later Robert Thurston saying almost no boilers exploded because of low water.

So why do boilers explode? We know the properties of steam: if you put a pot of water on a stove and heat it up, it boils at 212°. If you put a lid on it, it turns into a pressure cooker and raises the pressure inside the cooker. The water temperature inside will come up as the pressure increases. The basic properties of water. That's why pressure cookers work. The Sultana pressure of 145 psig means the operating temperature inside the boiler would have been around 363°. So the water is at 363°. If there is a break in the boiler and the pressure drops, what happens is that some of that water is now sitting at 363° and it goes to boil at a lower temperature, so the water boils suddenly, and that sudden boiling is what causes a boiler explosion.

Now, we know that when water goes to steam, it can expand up to 700 times. Expansion is the problem, and it's the quantity of water that creates the explosion. This can be hard for some people to understand, so I came up with a little demo. This soda bottle is a boiler. If you have a small leak in it, the pressure drops. As the pressure drops, the carbonation -- or the steam, if it was a boiler, -- comes out. So you can see that the bottle can contain the pressure, and it stops. If you have a larger leak, it's much more dramatic. Now, look inside the bottle. Do you see how quick that is? Look at all of the white in the bottle. That's all the carbonation being released at once. So that's what the difference is, and that's why this is so powerful. You can see how quickly it stops once it gets down to less pressure.

You can do the same thing with a can, as in this example. Notice that the can split along the horizontal line, which makes sense to all of us who work with the Code, because that's the direction weakest under stress. Now, the expansion power split it open like a fish mouth. Again, there is still power behind it, so it actually rips it from the edges. This matches the descriptions of the Sultana from the people who looked at the Sultana wreckage. It also matches all of the descriptions and all of the hand-painted drawings in textbooks from 1865.

Here is a boiler from 1879. It ripped right at the seam and peeled back from the edges. We know now there was no careening, we know why boilers explode. So why did the Sultana boilers explode? Let's look at the Sultana boilers themselves. There were four boilers on the Sultana. They were fire tube boilers. They were made out of charcoal hammered No. 1 iron, 17/48ths inch thick. I don't know how they measured that that closely. They were four feet in diameter, 18 feet long, had 24 five-inch flues. They were designed for 145 psig. Now, there were regulations in effect at the time. The Steamboat Safety Act of 1852 was in effect. They did have safety equipment. They had two safety valves, they had two water and one steam gauge, and they had a safety guard fusible plug. Now, some people claim that I'm really into this and I get super-excited and I put way too much time into this, so to my defense, there is a guy that did his thesis on the safety guard fusible plugs. Again, I pulled up his thesis. It's 400 pages just on the plug. And believe it or not, it's out there. I can show it to you. So I'm not the worst, believe it or not.

We know that these boilers were in poor condition. We know from the testimony that at least one of the boilers had burnt plates at the bottom. We know that two days before the explosion, the boilers had been repaired in Vicksburg. From testimony from one of the employees, the boats had also been repaired the month before in Natchez, Mississippi. When R.G. Taylor looked at the boiler, he said the tubes were in great shape. The tubes were in great shape because this boiler had already been retubed. So this is a boiler that's not even three years old; it has burnt, blistered plates; it has been repaired twice in the past two months; and it had already been retubed. This boiler was in horrible condition and was almost destined to explode.

So why was this the case, why was it in such horrible condition? Three factors. The first is the iron, the material of construction. Charcoal hammered iron was the best available at the time, but we now know it wasn't good material. So what do they do to make wrought iron? They have a puddle water system and they pull out plumes -- they call it plumes of iron, and they will hammer it together. So as you can see in the top picture where those two plumes are hammered together, you can see the different colors, you can also see the inclusions and the inconsistencies in this material. Putting together this wrought iron was almost an art at the time. It really wasn't the science that we have now.

In the bottom picture you can see the inclusions and how nonhomogeneous the material is. And in this one, those inclusions were busted up and actually had rust in it, and it created this split. Now, as we know, material properties and material construction gets better and better as time goes on, so by 1879 there is another type of iron called flange iron that was a preferred boiler material, and charcoal hammered iron -- and this is a statement from the books -- is not suitable iron for boiler construction. Having but little elasticity and breaking with a sudden jerk, it's of brittle character. The other thing that happens and the other thing the book talks about is that the iron gets more brittle when it is heated and cooled, and heated and cooled repeatedly. So that happens with this iron because of the water chemistry. I'm talking really bad water chemistry. You may think you have seen bad water chemistry, but these boilers used straight Mississippi River water. They didn't have water softeners or filters.

Every ounce and amount of water was taken in from the Mississippi River. There is a quote attributed to the famous author Samuel Clemens: the Mississippi River is too thick to drink and too thin to plow. And that's the water that went in. We have USGS data from the 2011 report that says there is about a half a pound of sediment for every thousand pounds of water. When this sediment gets on the bottom of the boiler, it causes scale and encrustation.

Here is a picture from the text from 1872 that shows the whole bottom of the boiler and sometimes in the plates and where the seams have sprung, but also this accumulation at the bottom. It acts like an insulator so the iron is no longer covered by the water, so the heat underneath causes this iron to get hot, and then when the boilers cool off, again, the cooling, heating, cooling, heating, makes a very poor iron even more brittle. So this is one of the factors.

This is a picture of a typical two-flue boiler design that was on the Mississippi River at the time. The fires would be along the bottom and they would heat the bottom up and it would make the turn and then go through the flues. Now, these two dual-flue boilers are very generous in size so you can get in and clean them, and it allows for lots of circulation. You had mud and everything in suspension. The Sultana design, however, was one of the first tubular boilers on the Mississippi River. It had 24 five-inch tubes. The chief engineer said when they went into the docks, they hired local boys to go in and scrape down the top. They couldn't get down far enough to scrape the bottom, so they just used a broom to try to pull it out. You know that sediment gets hard and you couldn't get it out with a broom. So again that design would prevent good cleaning of those boilers.

Now, after the Sultana, in 1866, there were three additional tubular boiler explosions in very rapid succession, and they killed quite a few people. This resulted in removal of tubular boilers from the Mississippi River. There are newspaper articles from the day that talked about getting rid of tubular boilers and how they were a bad, unsafe design. There were also advertisements that said: “Come to our steamboat line, we only use the dual-flue boilers.” There were people who actually removed tubular boilers from their boats and replaced them with the dual-flue design. The tubular boiler design was a poor experiment for the conditions.

Now, another aspect of the design that's important is it was a single lap design. It wasn't a rugged design; it was a single lap. And we know that that's the spot in the boiler where it ripped right at the seam. So it was these three things that caused the magnitude of the explosion. It was the quality of the iron. This is brittle iron that gets even more brittle when it's overheated, so it would just take a little shock to create a big explosion. There is the Mississippi River mud that settled on the bottom that allowed the bottom of the boiler to get burnt. We had testimony about the boiler repair. And then part of the testimony from the person who pulled out the wreckage and saw that the sheets were burned and in bad condition.

Then we have a design that was not suited for the conditions. It was very hard to clean. And we know that these tubular boilers were removed from Mississippi River steamboats. Sounds good, but let's look at data. Here is data that came from the locomotive articles from 1880. We have the information that the plates were burnt. We know there was an improper or incomplete repair that was done. We have data from England actually from 1865 that showed 50 percent of all explosions in one year in England initiated at the seam. The data shows that 38 percent of the dangerous conditions that we inspected for at the time were burnt, blistered plates with sediment scale. So the information backs up what the intuition, based upon the testimony, shows.

The Sultana was a big explosion and it was very dramatic and it is important, but it's not the only boiler explosion. Boiler explosions, as you heard earlier, were still going on. And that's really what the Hartford Steam Boiler and those two men that I talked about, Jeremiah Allen and Edward Reed, were really looking at. Here is data from 1868. There were 94 explosions killing almost 250 people. If you have ever heard that statistic, one explosion every four days, this is the data that it came from. This is the very first application of the very first tabulated data in one of the Hartford Steam Boiler logs. And I want to tie in Hartford Steam Boiler and its relationship with National Board and the ASME.

The Polytechnic Club was formed in 1857. The constant number of explosions is what motivated Jeremiah Allen and Hartford. This group of men got together, and they included Pratt and Whitney, who were big manufacturers with Hartford, and they had the idea of insurance and inspection tied together. However, the Civil War got in the way, and it was after the Civil War, after the Sultana explosion, that those two men decided they were going to start an insurance company. And they did. HSB was incorporated in 1866.

The first meeting with ASME was 1880. After some other boiler explosions, like the 1905 Grover shoe factory explosion in Brockton, Massachusetts, the focus really started on boiler and pressure vessel codes. The ASME Boiler and Pressure Vessel Code was published in 1915, and then The National Board of Boiler and Pressure Vessel Inspectors had their first meeting of chief inspectors in 1919. So Hartford Steam Boiler, ASME, and National Board are tied together, and I'm proud to be here today to talk to you guys.

In closing, the story of the Sultana is not merely a history lesson. Yes, boilers blew up and many lives were lost, but it's much more than a history lesson. It's a reminder to all of us. The captain overloaded the boat and took bribes. They knew that the boiler sheet repair was incomplete. The army captains allowed all of these men to be put on the boat. So it's this culmination of factors that created the disaster, along with the explosion.

The story of the Sultana is a reminder of the power behind boilers. It's a reminder of the work that you do. It's a reminder that you cannot be complacent. You have to pay attention, and when you hear something that doesn't seem right, question it, because the work that you do makes a difference. Thank you.