A New Look at the Explosion That Caused the Sultana Disaster

A new look at the explosion that caused the Sultana disaster

In the early morning of April 27, 1865, While the boat was rated to carry just north of Memphis Tennessee, 376 total passengers, it was packed three of the four boilers on the with over 2,400 people. The Hartford Steam Boiler Sultana steamboat exploded. Samuel explosion, ensuing fire and cold One State Street Clemens (not the famous author) Mississippi river claimed more than P.O. Box 5024 was the engineer on duty that night. 1,700 lives and this tragedy remains Hartford, CT 06102-5024 He suffered severe scalding and died the largest maritime disaster in Tel: (800) 472-1866 www.hsb.com later that day, after giving testimony U.S. history. The majority of the to the first investigators. passengers were men returning May 2015 home after surviving horrendous One woman, a member of the conditions in Confederate Patrick Jennings Christian Commission, whose name prisoner-of-war camps, who Principal Engineer is forever lost, calmed a group of anticipated reuniting with their men hanging onto ropes while the families and friends. boat, full of flame, drifted down the Mississippi. As the fire approached The sinking of the Sultana occurred her, she didn’t want to panic the in tumultuous times; which included men so she stepped backward into the deaths of Abraham Lincoln and the fire rather than jumping in John Wilkes Booth, the surrender of amongst them. Lee’s army and the effective end of the Civil War. All of this occurred in Joseph Test, a soldier from Ohio, was the month of April, which relegated killed almost instantly by a piece of the Sultana to the back pages, where timber blown into him from the force the story was nearly lost to history. of the explosion. We know about Joseph because of his friend, who This research examines the factors had the most unusual story of the that led to the boiler explosion survivors. Joseph’s friend couldn’t through eyewitness accounts, find any wood to use as a raft so he testimony to investigators and at ran to the boat’s mascot - an alligator trial, as well as texts describing boiler - stabbed it three times and then technology and knowledge of the used its wooden crate as his life time. It also discusses and rebuts raft (Berry, 1892). popular alternate theories.

Figure 1 - The Sultana burning Hartford Steam Boiler Page 2/9 A new look at the explosion that caused the Sultana disaster

Boiler explosion theory 1. There is a tremendous amount which water boils will decrease. of energy stored in a boiler under At this point the water temperature In the early years of steam use, pressure, and almost all of this will be greater than the boiling boiler explosions were common, energy is in the water. temperature. Therefore, some of the yet misunderstood. At various times water flashes to steam, expanding explosions were blamed on acts of 2. A sudden drop in pressure and re-pressurizing the boiler. God, spirits, electric generation will cause a portion of water to within the boilers or hydrogen instantly boil creating steam; each If the leak or opening in the boiler is caused by the disassociation of cubic foot of water then expands up small and the boiler strong enough, water in the boilers. By 1865, it was to 1,600 cubic feet of steam. This the boiler contains the pressure and generally accepted by boilermakers expansive power is what creates the water or steam slowly leaks out and engineers that the cause of most catastrophic explosions. and the boiler pressure slowly boiler explosions was low water decays. However, if the boiler can’t (Thurston, p. 36). Figure 2 (Thurston, p. 26) is a table contain the pressure due to a from Thurston’s book that shows the weakness, more and more water In this theory, low water caused a amount of energy stored in a boiler. flashes to steam and continues to boiler plate exposed to the fire to According to this data, the energy rip the openings wider - almost overheat and turn red hot. It was contained in a plain tubular boiler instantaneously. For the Sultana, assumed that when water struck was sufficient to launch the boiler if the pressure in the boiler dropped the plate it instantly turned to 5,372 feet - over a mile high. The from 135 psig to zero, up to 950 lb or steam over-pressuring the boiler table also shows that the energy 15% of the water in the boiler would and resulting in an explosion. stored in the steam in the boiler is turn to steam. Each cubic inch of This didn’t explain many explosions less than 3% of the total energy in water expands to as much as one however, and there was often the boiler. cubic foot of steam or 1,600 times vagueness in the explanations that the volume. It is this tremendous referenced unusual circumstances Water boils at 212°F under normal expansion that results in the ferocity and the power of gunpowder. conditions. If boiling water is of the explosion. At the time of the contained, as in a boiler, the pressure disaster, this knowledge of boiler Engineers recognized that a sudden increases and the temperature at explosion theory was incomplete burst of steam generation was which water boils increases. At the and led to the most commonly cited, occurring, but did not understand Sultana’s normal operating boiler but incorrect, theory of the explosion, the incredible amount of potential pressure of 145 psig, water boils at a combination of low water and energy stored in a boiler, nor how the 363°F. If there is a leak or break in careening of the vessel. sudden burst of steam generation the boiler, the pressure will drop occurred. Detailed scientific and therefore the temperature at investigations of steam and steam properties took place in the early 1860’s, but the first tables that documented steam properties weren’t issued until later.

In 1887, Robert Thurston, who was the first President of the ASME, published “Steam Boiler Explosions, In Theory and Practice” and by that time, the science was well understood and the two key things that earlier generations of engineers did not know were that:

Figure 2 - Stored energy of steam boilers Hartford Steam Boiler Page 3/9 A new look at the explosion that caused the Sultana disaster

Low water and careening of the boat

Engineers in 1865 did understand that it was a sudden burst of steam that created boiler explosions. However, in the case of the Sultana they thought that this burst of steam was due to a low water level and careening of the boat.

According to this theory, as the boat rocked, or careened, the boiler was exposed to the heat of the fires without water covering and cooling it. This iron turned red hot and when Figure 3 - Sultana at Helena Arkansas the boat rocked back, the water striking the red hot iron flashed to steam creating a sudden pressure In 1865, boiler engineers, captains It is possible to calculate the surge and subsequent explosion. and others in the trade believed theoretical steam generation by that a boiler full of water could not a red-hot section of iron. This The emphasis to this day on this explode (Thurston). This was stated calculation shows that the red-hot explosion theory is due to the directly in the testimony of R.G. iron may double the amount of large amount of testimony that Taylor, who said, “So long as there is steam in the boiler from 16 to 32 lb discusses careening and low a sufficiency of water in the boiler of steam. This is 60 times less than water. In the records, Isaac West, there is no danger of explosion the 950 lbs of steam that could be W.B. Richardson, J.J. Witzig, and (Archives, 1865). “ generated due to a break in the Chief Engineer Wintringer all noted boiler. Therefore the pressure that that careening of the boiler may Therefore when reading the can be generated by a careening have been the cause of the explosion testimony, it is important to event is significantly less than the (Archives, 1865). Of these four, understand that they didn’t have pressure that can be created from three were not present on the boat today’s knowledge of steam theory or a full boiler with a simple break. and the fourth, Chief Engineer why boilers explode. As the physics Wintringer, was asleep at the time behind the immense power of steam Maintaining a proper water level of the accident. explosions became known, the is critical to ensure that the heat pendulum swung the other way and absorbing tubes are covered in The prosecution at the trial of by the late 1800’s some believed that cooling water and generating steam. Captain Frederic Speed asked no explosions were caused by low The engineer on duty the night of the multiple questions regarding the water (Thurston, p. 36). We now accident was Samuel Clemens, who careening of the boat. Due to the know that introducing water into a died shortly after the accident from large number of troops on board and hot boiler can cause an explosion the injuries he received. the small amount of cargo in the under the right conditions, but is hold, the boat did rock when many fortunately, a rare event. According to Wintringer, Clemens men rushed to one side, most notably had been working around boilers during the last picture taken of the There are two areas of investigation for about 25 years and the Chief Sultana in Helena Arkansas, shown that counter the careening water Engineer considered Clemens an in Figure 3. theory. The first is to calculate how able engineer. He clearly understood much steam may be generated in a the need to maintain a full boiler. It boiler during a careening event and was reported that he stated the compare that to the theory presented boilers were full of water. In his short in this research and the second is to testimony before he died, he did note review testimony from people who that as the boat was light, it did roll were on the boat and awake at the during the trip. Even though Clemens time of the explosion. noted that the boat was light and Hartford Steam Boiler Page 4/9 A new look at the explosion that caused the Sultana disaster

rolled, he did not place the blame Boiler Weakness on made it to Vicksburg where chief on low water and careening, but on the Sultana engineer Wintringer contracted defective repairs (Archives, 1865). R.G. Taylor, a boilermaker with 28 The steamboat was inspected on years experience, to repair the boiler. “All was peace and no sign of April 12, 1865 in St. Louis, Minnesota The repair consisted of a patch that disaster. I spoke to the engineer of by federal inspectors John Maguire was 11” x 26” along the straight seam how nicely we were going…” stated and John Schaffer in accordance of the third sheet. This size patch George Clarkson, a survivor who was with the Steamboat Act of 1852. was the length of the seam for one awake at the time of the explosion The boilers were subjected to a boiler plate (approximately 2’) and (Berry, p. 94). If the boat was rocking hydrostatic test of 210 psig and sufficient width to cover the seam enough to expose the bottom of the deemed acceptable (Inspector’s area. The area near the seam was boiler for a period of time long Certificate, 1865). Although they bulged out and this patch was enough to heat it to red hot, it would were deemed acceptable, there is fitted to the bulge. The boilermaker have been noticed. substantial evidence that these considered the patch only a boilers had incurred damage over temporary repair and he stated that At the time of the explosion, the two years of operation. the chief engineer had agreed to men were mostly asleep (and not make a full repair in St. Louis. moving side to side) and there was With the clarity of hindsight, this is According to Taylor’s testimony, a no mention in any of the survivors’ no surprise. As the experience and full repair would have consisted of stories of careening before the knowledge surrounding boilers forcing back the bulge and replacing explosion. In a letter to the Secretary increased during the latter half of the two sheets adjacent to the patch. of War dated May 19, 1865, General the 1800’s it became clear that While he considered the patch a Hoffman noted that “There is nothing weaknesses due to wear and tear good job, he did not believe the to show that there was any careening on the boiler had caused many boilers were safe (Archives, 1865). of the boat at the time of the disaster, explosions that were formerly or that she was running fast; on attributed to other causes. “Without While the leaking seam is one the contrary, it is shown that she becoming marked in any one part of indication of weakness, Taylor’s was running evenly and not fast place such wear steadily reduced the testimony indicates that the boilers (Berry, 1892).” factor of safety represented in the had suffered “burnt plates,” which boiler as originally made and might he suspected were the result of A boiler explodes when the internal eventually result in an explosion far operation with low water (Archives, pressure is greater than the pressure more destructive than one growing 1865). It is more likely that the retaining ability of the boiler. This out of a more obvious defect or cause of the burnt plates was the can occur when a drop in pressure weakness (Hunter, p. 295).” The accumulation of sediment in the creates a sudden release of steam evidence that the Sultana had boiler, which will be discussed below. that then over pressurizes the boiler. been weakened includes a recent Although he suspected low water In the case of the Sultana, the repair history - one of which was conditions, he noted that the flues evidence is clear that the boilers incomplete - burnt boiler plates were in good condition with no were weakened and based on the and an earlier re-tube of the boiler. defects. They were in good condition results, could not withhold the because these boilers had already steam. This boiler explosion On the final trip upriver, between been re-tubed once (The Sultana knowledge was unknown to New Orleans and Vicksburg, the Disaster, 1865). engineers of the time and it follows boiler developed a bulge and a leak. that boiler explosions are more likely The leak was in the inner larboard The one piece of boilerplate retrieved and more damaging if the boiler has (left) boiler. It was noted as being on from the wreckage was burnt weak points. The boilers on the the third sheet from the forward end, (Argus, 1865). This matches Taylor’s Sultana had known deficiencies. a few inches below horizontal, and description of the plate. While it is was located in the outer seam with possible that the fire on the Sultana cracking noted between two to three was responsible for the burnt look of rivets. Cracking between rivets at the this plate, it is clear that the plates seam was a common and well-known were in poor condition at the time of concern for riveted boilers. The boat, the explosion. W.B. Richardson, Chief operating under reduced pressure, Engineer of the steamboat Marble Hartford Steam Boiler Page 5/9 A new look at the explosion that caused the Sultana disaster

City who examined the recovered Material of boiler piece noted the burnt look and construction stated that the iron was of “very poor quality.” The explosion tore While the iron used in the boiler the piece transversely (at right construction, Charcoal Hammered angles from the length) from the No. 1 (CH 1), was the best quality boiler and that at its widest was material available in 1863, CH 1 iron the width of a sheet (Archives, 1865). is not a suitable material for boiler This is very typical damage in construction. CH 1 iron is now known Figure 5 - Wrought iron plate with internal explosions caused by a sudden and to be unsuitable due to its method of corrosion and separation massive overpressurization. fabrication as well as its mechanical properties after being heated and As is common in many industries, Other evidence that the boilers cooled repeatedly. new technologies overtake older were in a weakened condition is ones, and this was the case regarding the recollection of Charles Lyda, CH 1 is a wrought iron that is heated iron manufacture for boiler plate an employee on the boat. He stated and wrought (or worked) with material. “A Practical Treatise on that in addition to the repairs in charcoal to increase the carbon High Pressure Boilers” by William Vicksburg, the boilers had also been content, which increases material Barr provides a review of boiler repaired the prior month in Natchez. hardness. The process of making material available in 1879. By then, This means that the repair in charcoal hammered iron leaves another grade of iron called Flange Vicksburg was the second repair imperfections that weaken the iron Iron was the preferred marine boiler in two months. Charles Lyda felt plates (Figure 4). These are seen as material. CH No. 1 iron was noted that the boilers were not in good black lines in the plate. Based on the as “Not a suitable iron for boiler condition (Berry, 1892). construction techniques of the time, construction.” This iron was there would have been inclusions considered an unacceptable These boilers were in a bad and imperfections in the iron used in material due to its “Having but condition, almost destined to the boilers, as well as poor control of little elasticity and breaking with a explode. While these boilers were other elements such as sulfur. In sudden jerk (Barr, p. 22).” In addition, under three years old they had been addition to weakening the plates, Barr noted that as CH No. 1 is heated repaired twice in the previous two the inclusions and imperfections and cooled repeatedly, it becomes months, had been re-tubed earlier can be locations for corrosion to very brittle. George Tower, in his and the condition of the existing occur. While the material may look contemporary book “Useful Things sheets was suspect. These acceptable on the surface, it is often to Know about Steam Boilers” also weaknesses resulted from the weakened due to the inclusions. Very noted that CH No. 1 iron behaves combination of several factors. often, the inclusions in iron can reach “most unsatisfactorily” and was of The first factor to consider is the the surface and allow corrosion to a “brittle character and unfit for use quality of iron used in construction. occur in the interior of the iron as in a boiler (Tower, p. 113).” shown in Figure 5. In this wrought iron sample illustrated, the inclusions The iron used in the Sultana boilers led to a complete separation near the contained inclusions, likely had surface as well as corrosion in the some level of corrosion and interior of the plate. We do not know became brittle when heated and the extent of corrosion of the Sultana cooled repeatedly. The boilers did boilers were, but some level of experience overheating on a regular corrosion is probable. basis and while overheating was often blamed on low water, the cause of overheating was due to mud and other impurities collecting on the boiler parts. These boilers used make-up water straight from the Mississippi river, which was the source of this sediment.

Figure 4 - Wrought iron plate showing internal imperfections Hartford Steam Boiler Page 6/9 A new look at the explosion that caused the Sultana disaster

Sediment in the Sultana boilers

The Sultana boilers used Mississippi river water with no filtering or treat- ment, and silt and mud suspended in the river water entered the boilers. On the Sultana, all the steam generated in the boilers was made up from this dirty river water. Sediment in the water collected on the boiler surfaces, particularly the boiler bottom which was exposed to the direct heat of the flame. This accumulated material acted as insulation, slowing the heat transfer from the metal to the water causing the plate to overheat. Blow-down or mud drums, as they are also called, were standard construction practice Figure 7 - Summary of 1879 inspection results at the time to help collect and get rid of mud or impurities. This One engineer estimated that in eliminate the hard, baked on would have helped eliminate some a 12-day run, a boiler would scale that tends to accumulate sediment, but even with this, the have ingested 200 tons of mud on the hottest sheets. The leak boiler needed regular cleaning and (Hunter, p. 263). It is possible to that was repaired in Vicksburg this was a well-known issue at the estimate the amount of mud that was near the fire bars. (Archives, time. The boilers were cleaned both the Sultana boilers would ingest 1865). In this area, the boiler is in New Orleans in March and in using United States Geological exposed to the hottest part of the Vicksburg according the Chief Survey (USGS) river water data fire where it sees both the direct Engineer (Archives, 1865). and boiler volume. Based on USGS radiant heat from the flame as well data from the 2011 Mississippi as the heat from the combustion According to a Hartford Steam Boiler flood, a straight average of the gases flowing over the boiler Locomotive article from 1880, scale sediment numbers results in value shell. W.B. Richardson testified and sediment, as well as burned or of approximately 500 mg per liter that the tear in the boilerplate blistered plates, were major concerns or approximately ½ lb of sediment appeared to begin “near the for many boilers - not just boilers on for every 1000 lbs of water. Therefore bottom,” another indication that the Mississippi river. each time a Sultana boiler was filled, this portion of the boiler was approximately 3 lbs of sediment weakened (Archives, 1865). was introduced. Based on the testimony indicating In addition to sediment, the water burnt plates and the known issues also contains dissolved minerals of sediment and scale, it is clear that that create scale, or as it was called the boiler iron suffered overheating. at the time - incrustation - of the This overheating cycling would have Figure 6 - Sediment and incrustation boiler. Scale also acts an insulator, led to the brittleness of the Charcoal again reducing the heat transfer Hammered Iron, leaving the boiler from the iron into the water. As a susceptible to a sudden failure. result, the iron temperature will be higher, which can lead to burnt plates (Tower, p. 106). Cleaning and scraping will not remove hard scale on boiler tubes or sheets. Even washing a boiler will not Hartford Steam Boiler Page 7/9 A new look at the explosion that caused the Sultana disaster

Steamboat Boiler Design of The Sultana had four fire-tube no longer used on the lower the 1860s boilers, each 46” in diameter and 18’ Mississippi (Berry, 1892). This long. In a firetube boiler, instead of change occurred after the The overheating due to the sediment two large flues, the boilers had explosions of the steamboats and the weakness of the plate was 24 flues (tubes) each 5” in diameter Walker R. Carter, Missouri and exacerbated by the boiler design. arranged in a staggered arrangement of course the the Sultana. Not There are two aspects of the design that carried the gases through the only were firetube boilers no that contributed to the weakening boiler. This larger number of smaller longer built for steamboats, many of the boiler. The first is the tubes increases the surface area boat owners replaced firetube arrangement of the tubes in the between the hot gases and the water, designs with the traditional two boiler, and the second is common to significantly improving both boiler flue design (Hunter, Perils of River all boilers of the time and relates to efficiency and capacity. With this Navigation, p. 158). the joint between the boiler sheets. design, the spacing between tubes or between the tubes and the The second design aspect that The standard boiler installed on bottom would have been very tight, was detrimental is the method of steamboats was a dual flue boiler as indicated in Figure 9. joining two sheets together. A boiler set into a casing above the firebox. is cylindrical because that is the In a typical design, the boilers were strongest shape for withholding arranged in a battery of 3-4 boilers pressure. As was standard practice located side by side on the boiler of the time, this boiler had lap joints deck. The fires were under the front where the plates were overlapped of the boiler and the flames and heat and riveted together. Lap joints in traveled underneath along the shell longitudinal seams are problematic bottom. At the rear, the combustion because the joint breaks the gases turned and entered the dual cylindrical shape of the shell. When flues transferring heat to the water pressurized, the shell wants to in the boiler. This two-flue design become cylindrical which can flex provided sufficient space inside the the sheets in the joint area. If not boiler to remove sediment and scale, carefully made, this flexing can be and supported circulation to keep significant and will eventually lead the sediment in suspension and to cracks forming, most often at the allow it to be blown out through Figure 9 - Firetube boiler layout weakest part of the sheet between the mud drum. rivet holes (Moedinger, 2014). In a While the design is more efficient, British report on steam boiler it significantly worsened the explosions in 1865, half of the sediment problem. The number, boilers that had exploded did so location and close spacing of the at the lap joint due to grooving tubes made it difficult to clean the where the forces were concentrated boiler. In addition, during cleaning, due to the shape (Thurston, p. 121). the condition inside the boiler would have been hard to see. J.J. Witzig, the Supervising Inspector of the Fourth District, noted this after the the Sultana disaster. This boiler Figure 8 - Double Flue Boiler design was not suited to the harsh conditions of the Mississippi, and both Nathan Wintringer and Charles Lyda noted that the tubular boiler design was “done away with” from operation in steamboats and Hartford Steam Boiler Page 8/9 A new look at the explosion that caused the Sultana disaster

Summary of the root cause of The allowable pressure has a safety Summary the Sultana explosion factor above the anticipated bursting No one goes to work thinking that his point. Taking out the safety factor or her decisions may kill over 1,700 Unfortunately for the 1,700 men, that is used for design, if the patch people, including themselves. But women and children on board, the was good material and applied indeed, the decisions of those condition of the boilers, the burnt correctly, it theoretically would have involved combined to result in the plates and the history of repairs on been capable of holding pressure large loss of life. The boat captain the Sultana all point to an explosion over 300 psig using current who accepted more men than as inevitable. calculations. While Witzig was allowed, the Army personnel who correct that the thickness of the crowded men on one boat while Three factors are included in the boiler patch would have lowered the other boats left the same wharf root cause of the explosion. The first allowable working pressure, it was empty, the boiler repairer who was the poor quality, brittle iron. This unlikely the patch material thickness performed a job he felt was iron was made more brittle due to the itself was the cause of the explosion. incomplete and the first engineer overheating caused by the insulating and captain who pushed for this effect of the mud brought in with Sabotage incomplete repair; all of these men’s the Mississippi river water. While There was some suspicion at the decisions contributed to the tragedy. other boilers on Mississippi time, which persists to this day, that Investigating and analyzing the steamboats could usually tolerate the boiler may have been destroyed cause of the boiler explosion is one this combination, it was the third by the sabotage of Confederate small part of understanding the factor - the design of the boiler - that spies that used of a coal torpedo. events that led up to the disaster made it hard to clean. A coal torpedo is an iron casting on April 27, 1865. that resembles a hunk of coal, and These three factors caused the mag- is filled with gunpowder, dusted During the second half of the nitude of the disaster. All it took was with coal and put into the coal bins. nineteenth century, great strides one little break and a drop in pres- The suspicion of the day makes were made in boilers; in theory, sure to unleash the steam’s power, as sense due to emotionally charged operation and materials of the boiler clearly could not handle feelings at the end of the Civil War. construction. However, in 1865 the sudden pressure. In reviewing the The evidence for this theory is only when the Sultana exploded, testimony, the Sultana history and circumstantial, and is based on a this knowledge was absent, and boiler explosion data, the most likely reported confession years after stepping back to the time period culprits of this initial break were the the explosion. to understand this is vital to burnt plates at the bottom or a seam understanding the cause of the that suffered the same damage as Based on forty years of western river explosion. The cause of the explosion the one repaired in Vicksburg. data, 30% of all steamboats suffered is straightforward; it was the result of accidents. While snags were the a poor quality material, overheating After the careening theory, there most common cause of steamboat due to Mississippi sediment are two other common theories that accidents, boiler explosions were accumulations and a design not are often cited as the cause of the the second. Approximately 1 out of suited for the water conditions. explosion; improper thickness of the every 5 steamboats that suffered an This theory requires no assumptions repair patch and sabotage. accident experienced a boiler or constructed scenarios, fits the explosion (Hunter, p. 1949). Boiler testimony (noting the lack of The thickness of the patch used explosions on the Mississippi river knowledge at the time) and matches on the Sultana boiler repair were common and there is a the common causes of boiler Another theory that is discussed preponderance of evidence that the explosions in the period. is based on statements from boilers were weakened due to the J.J. Witzig. In his testimony at the material, the design of the boiler and The tragedy of the Sultana should trial of Captain Speed, he stated sediment in the water. The firetube not be forgotten. Understanding the the allowable pressure based on design of the Sultana was an causes of accidents allows us to 0.25” iron would have been 100 psig experiment on the lower Mississippi prevent others, and today’s improved (Archives, 1865). He also repeated with additional explosions attributed boiler designs and inspection this in his section of a report by the to this boiler design, which was regulations are the result of the loss Secretary of the Treasury (Treasury removed from use shortly after. of the Sultana and other notable Department, 1865). boiler explosions. Hartford Steam Boiler Page 9/9 A new look at the explosion that caused the Sultana disaster

For further information, watch the video of Pat’s presentation Works Cited on his Sultana research at go.hsb.com/sultana150 Archives. (1865). Sultana Records.

Argus, M. (1865, May 11).

Barr, W. M. (1880). A practical treatise on high pressure steam boilers. Indianapolis: Yohn Brothers.

Berry, C. D. (1892). Loss of the Sultana and Reminiscences of Survivors.

Hartford Steam Boiler Inspection and Insurance Co. (1880, February). Yearly Summary of Inspections for the Year 1879. The Locomotive, p. 28.

Figure 1 - The Sultana burning Hartford Steam Boiler Hoffman. (1865, May 19). Letter to the Secretary of War.

Figure 2 - Stored energy of steam boilers Hunter, L. C. (1949). Steamboats on the Western Rivers. From Thurston - Steam Boiler Explosions, in Theory and Practice Toronto: General Publishing Company, Ltd.

Figure 3 - Sultana at Helena Arkansas Inspector’s Certificate. (1865, April 12). St. Louis. Photo from Library of Congress http://www.loc.gov/pictures/item/2013647457/ Moedinger, L. (2014). Personal Correspondence. Figure 4 - Wrought iron plate showing internal imperfections Photo by Patrick Jennings Perils of River Navigation. (n.d.). Retrieved February 13, 2015, from Chronicles of the American Civil War: Figure 5 - Wrought iron plate with internal http://www.cw-chronicles.com/cw-documents/sultana-005.htm corrosion and separation Photo by Patrick Jennings Potter, J. O. (1992). The Sultana Tragedy. Gretna: Pelican Publishing Figure 6 - Sediment and incrustation Company, Inc. Graphic from “Records of Steam Boiler Explosions”, by Edward Bindon Marten, London 1872 Salecker, E. G. (1996). Disaster on the Mississippi. Annapolis: a Project Gutenberg eBook. Naval Institute Press. Figure 7 - Summary of 1879 inspection results Table from “Locomotive” The Sultana Disaster. (1865, May 4). NY Times. New Series Vol. 1 No. 2 February 1880

Figure 8 - Double Flue Boiler Thurston, R. H. Steam Boiler Explosions, in Theory and Practice. Graphic from “Records of Steam Boiler Explosions”, by Edward Bindon Marten, Tower, G. (1885). Useful Things to Know about Steam Boilers. London 1872 a Project Gutenberg eBook. New York: American Steam Boiler Insurance Co.

Figure 9 - Firetube boiler layout Treasury Department. (1865). Report of the Secretary of the Treasury Graphic by Matthew DiMascio (HSB) on The State of the Finances. Treasury Department.

Note on the Archives. The National Archives has a collection of records on the three commissions that investigated the explosion (Washburn, Hoffman, Dana) as well as the trial of Army Captain Frederic Speed.