I learned it school that it sank from the blast of its own torpedo. I haven’t kept up to date with new civil war discoveries so can you elaborate on the series of events?
TLDR: Bomb the size of a beer keg + 16 foot poking stick = bad for your health
It had a spar that was 16 feet long, and at the end of that spar was attached a bomb made out of thick welded copper and containing black powder. Historical records vary, but imo the most robust records indicate it had 200 pounds of black powder inside (91 kg). That would have made it about the size of a beer keg!
On February 17, 1864 the crew of eight cranked the HL Hunley up to the side of the Union ship USS Housatonic, which was part of the blockade outside of Charleston Harbor. The bomb - called a torpedo, which meant a stationary explosive at the time - had pressure triggers, and once those little horns pressed against the Housatonic's hull, the bomb went off.
The submarine was recovered in 2000 and raised, but when it was opened as part of the conservation efforts, the skeletal remains of the crewmembers were found still seated at their battle stations. In previous sinkings, they had been found trying to escape through the fore and aft hatches. This time, in contrast, it seems they just sat down and died.
Theories have abounded ever since, with the oddity of the crew positions fueling passion for this apparent mystery. For me, as a blast specialist, those were all the hallmarks of blast trauma. However, in science, if you don't have data, you're just speculating, and so it was then a mission to get data to assess the plausibility. Also to explain HOW. If the hull of the boat was intact, HOW did they die of the blast? And how do we explain the other quirks of the historical records, like the blue light?
The rest is blast physics! And honestly probably too much for a comment-level explanation. I did write a book about the story where there is a whole chapter about blast trauma, but I'm trying to stick to the subreddit rules and not self-promote and instead just enjoy this history nerd moment together. So, if you want a free version, the book is heavily excerpted in this piece for Smithsonian Magazine, and that includes more details on the blast-level explanation.
Pretty sure her research is actually what provided the hard proof for that theory. Definitly curious to hear the exact breakdown of the timeline though.
Oh, hi!! It's not clear who you are from your profile (sorry), but do DM if you'd like to say hi. Pass my hello back to everyone in Panama City too, please. Dang do I miss the diving there.
I think this will surprise everyone, but I enjoyed investigating the disappearance more, because I was doing that in archives with HVAC and chairs. The scale model work was thrilling when the live charges and gauges all started working in concert and we got results, but there was quite a bit of trial and error before that. Despite having access to serious experts in both fields (I collaborated with my ATF agent, who knew a ton about black powder, an Army EOD guy with tours dismantling IEDs in Iraq, and fellow US Navy civil servants who built and used the gauges), there were just a lot of things about these experiments that were combinations of things nobody had done before or in a very long time. SHOCKINGLY, I could not find anyone else alive who had built Confederate black powder submarine torpedoes before, I KNOW RIGHT!!!
Then of course there was the weather. We were very exposed to the elements, and a lot of the days were rough.
So, yes, there were some absolute high points in the experiments, and I will remember them forever with a smile. But overall, like with most science there was a lot of failure before there was success. The archives, however, were always guaranteed to have old papers. And chairs.
In Afghanistan whenever we would hit an IED one of the biggest things we learned to worry about was the proximity to the blast radius. It was making our folks’ lungs unable to process air due to pressure damage. Even a few meters of distance could be the difference between life or slow death. How much did that play a role here or were they just knocked unconscious?
Yes, absolutely. That was my leading theory of what happened to the crew. There's a lot more detail in the book In the Waves, where I do go into examples from Iraq and Afghanistan and even one wild experiment where they showed blast transmission into armored vehicles (not at fatal or injurious levels, but still, DANG). That being said, it seems like you're thinking exactly like I was, which is:
Bomb the size of a beer keg + 16 foot poking stick = bad news
With blast, it's unlikely that someone is knocked unconscious without also experiencing lung damage, unless their lungs are somehow protected. Modern bulletproof vests do a magnificent job of protecting the lungs from blast, which is the evidence-backed theory of why Iraq and Afghanistan were the first wars where we started seeing such large numbers of TBI. The "glass half empty" perspective of blast-induced TBI is that those are people who probably would have been dead without modern lung protection. However, as you've pointed out, they're not perfect, and if someone isn't wearing a vest, then lung damage happens pretty readily, and I personally think that's what killed the crew.
On top of that, the brains of some of the crewmembers were present upon recovery. They show extreme changes from being in saltwater for 150 years, but they also show dark stains on their surfaces consistent with blood. A stain of blood on the surface of the brain is what fatal TBI from blast looks like. The Friends of the Hunley have never permitted the release of the MRIs, but they show them onscreen during a National Geographic documentary. I've added a screen grab to the images of the crew remains here.
There was also a theory that the bomb caused the sub to buck and heave in such a way that the crewmembers were knocked unconscious from the blunt force trauma of hitting their heads on the hull. While I think this is an interesting theory, there's only a narrow window of force between where you get knocked unconscious and where you have skull fracture, and the odds of eight people being hit in the head with that same level are very very small. None of the skulls showed any signs of blunt force trauma. Blast, in contrast, does not leave a mark on the skeletal remains including the skulls (below the levels where you get tissue disruption, of course).
Was it possible to determine if their ear drums were ruptured from their remains? If brain tissue was still intact then ear drums might also have survived. Bleeding from the ears was a strong indicator of distance from detonation for us.
I’ve read both of your books! What do you think of Project Azorian and the difficulty of raising K-129, would we have an easier time now with improved understanding or are the problems intractable?
THANK YOU!!! I'm so excited you've read my books and (hopefully) liked them!
Ohhhhh the K-129, I love it so hard. To be honest, I think the biggest problems with a scenario like that is that the ocean has tricks up her sleeve and it is impossible to predict them until the day you try. With a wreck, too, there are almost always unanticipated aspects of position, damage, etc. You can't count on the hulls to be as intact as they were in the moments before the sinking, you don't know if you can count on them to hold while you try to raise it.
It's just a tough question for any engineering problem, to be able to anticipate and plan for all of the possibilities before you're even onsite.
Based on your experiments, do you think the crew was aware of what was happening in their final moments, or would the blast have incapacitated them instantly?
I don't think they were aware. I think they knew they were getting close to the USS Housatonic and then.... lights out.
There is a non-zero chance for each crew member that they survived. When you apply that to eight people, it is possible one of them survived the blast but had only severe lung damage. There was an extremely high chance of severe lung damage, so it's unlikely any survived without at least that. I think this little trick of statistics is extra fascinating when you compile it with the fact that the skeletal remains of the crewman at the #2 spot looks like he may have been trying to claw his way toward the fore hatch. It's not confirmed, of course, he could have just toppled off his bench that way too.
But can you imagine? Your bomb goes off, you have long enough to think YES WE DID IT, then with your next breath you feel like you're choking, you gag and see blood spray when you cough. You look around and all your crewmates are dead. The forward hatch is open, if only you can reach it... just maybe....
GREAT QUESTION! I saw this question yesterday and tried to find my old spreadsheet where I did the math after asking it myself. I am sad to report that I failed, as it was two computers ago (it's somewhere, just amongst all the backups).
However, by memory, I believe it was 22 feet. It was not necessarily the increase in length that would have saved them, though, but the change in the angle between the boat and the bomb. By having a slightly longer spar, that angle changed, and more of the blast would have been directed at the bow of the submarine. Per my experiments, the bow did not transmit very much blast, which makes sense because of its sharp angle and the fact that there is a water-filled ballast tank with layers of other material types between the bow and the crew (going through various layers of things usually has a reductive effect).
They were so close to making it. They just needed a bit more blast physics.
Fun fact, the Confederacy's official bomb expert, a man named Gabriel Rains, strongly recommended a longer spar. He even made drawings of one, where he included changing that angle between the bomb and the boat to put them more on an even level and have the bomb in front of the bow. Always listen to your explosives experts, kids.
Might be dumb questions: What would have caused them to go through hypercapnia before hypoxia? In flight school we're taught quite a lot about the dangers of hypoxia, but I'm not sure I've even heard of hypercapnia before.
From reading through what I've got access to, your research suggests that their torpedo exploded off their bow, the shockwave propagated through the sub, and killed or incapacitated all crew members at their posts, allowing the ship to slowly drift and sink.
Is there any way to find evidence of that on the ship? I would think there would be some sort of deformation or cracks near the explosion which could concretely prove your theory.
Not dumb questions at all!!! Very good questions, I in fact love the first one.
In flight school you were trained heavily on hypoxia because you're getting supplemental oxygen, and one of the biggest risks to aviators is that oxygen system failing and you slowly passing out. The Air Force did some nifty research showing that pilots who had been put through actual hypoxia experiences in a training environment had a 94% chance of recognizing that they were becoming hypoxic, whereas pilots who had only been told verbally about the symptoms but not experienced the physical hypoxia had a much lower chance of recognizing it during an actual emergency (I *think* it was only 6% but that seems to add up to 100% too neatly so I'm not going to trust my brain on this one. It was definitely below 25% though, so it was a big difference). Training for hypoxia has been the gold standard ever since!
Fun sidebar: when the SpaceX crew came to Duke for hypoxia and hypercapnia training, I was one of the inside tenders in the chamber for their altitude excursion, which means I was the one taking away and returning their oxygen masks and monitoring them during their period of lack of oxygen. Since the pilot was a billionaire, this means that I technically and truthfully get to say that I once suffocated a billionaire!
Inside any closed space hypercapnia will be a problem first because the people are breathing out the carbon dioxide into the space then rebreathing, whereas with aviation it gets released peacefully out into the world around you while your mask gives you more fresh O2. It's that effect of trapping the CO2 that makes hypercapnia an issue in enclosed spaces.
Hypercapnia becomes an issue first just because of the levels at which our bodies are sensitive to CO2 and O2. There's probably some evolutionary biology reason the levels are where they are, but that would require more thought, on a level that would require me to refill my snack supplies.
Second question: sadly, no, there is no way to find evidence of that on the ship.
There is of course a higher level of blast overpressure that will force the hull of the ship to flex inward in a way that permanently deforms the hull, but it's at a much higher level. I do have a picture somewhere of a WWII experiment with a mini-sub where they achieved this level of hull deflection and it's very neat, but I'm not finding it on quick search so I'll loop back and add it as an edit if I can dig it up.
Quick note: since it was black powder, it was not technically a shock wave, it was just a "pressure wave." Poor little black powder, so maligned as a little "low explosive" instead of a "high explosive." Otherwise you nailed it.
These photos show the results of underwater explosives against the hull of WWII X-craft, which were mini-subs built by the British during WWII. The later two photos show the damage done by underwater explosives against an X-craft used in combat, and obviously it was sunk. In both cases, the mini-subs were exposed to much higher pressure levels than the HL Hunley experienced, and from high explosives, which are more damaging. That's why, for these, that type of distortion of the hull was permanent. In the case of the Hunley, it was temporary and thus left no trace.
Yes, the blast physics has been done to know where the various thresholds are between "no hull flexion," "temporary hull flexion," "permanent hull flexion," and "tearing the hull apart," and the range of force where you can get temporary hull flexion of the type that would transmit the pressure inside to the crew without leaving a mark is quite large for the design of the Hunley. (wonderful paper by a blast physicist named Michele Hoo Fatt)
In our case, however, it's sad that no permanent damage occurred, as that would be nice supporting evidence, wouldn't it?
I was working as a civil servant for the US Navy for several years before going back to grad school, and I actually continued my navy employment during my time as a grad student, so I was making routine trips back to my base and was heavily mentally aware of the problems facing warfighters. Specifically, traumatic brain injury (TBI). When I started grad school I was actually studying a different topic but it involved almost entirely coding, which I respect and do sometimes, but was not working for me as an "all day every day" type of thing.
Down the hall was another lab that I hadn't known about before, and they were working on injury biomechanics, which is the use of engineering principles to study the physiology of injuries. A lot of people in that field work on car crashes, as did half of that lab, but the other half studied TBI. Since I was already heavily studied-up on respiratory physiology because of my previous work, and blast trauma involves lung damage first and easiest, it was a natural bit of overlap. I wandered down and asked if I could switch labs, and since I was funded by a navy scholarship, I was able to!
I started my PhD simply investigating blast trauma patterns from underwater explosions, kind of the nexus of my previous areas of expertise. I wrote a few papers on that, but one day my advisor asked me if I could apply the same principles to investigating the HL Hunley. I did not know what those words meant, but when he left my office I started googling. And the rest is r/history!
Oh you asked a second question didn't you. I'm always somewhat involved in the world of underwater blast trauma as there are a lot of open questions in that area. Right now I'm in the middle of a year-long sabbatical from hard science, but that's up in July. I cover other areas of underwater physiology as well, and have been slowly compiling historical data from a few topics in that world that I want to put together and analyze. Yes.... I am bad at "sabbatical"-ing.
Can you describe the working conditions of the sailors inside the Hunley? How uncomfortable was it? Temperature, humidity, fresh oxygen? How cramped and for how long at a time? How did they go to the bathroom?
Extremely uncomfortable, no chance of escape if it went down. Cramped and oxygen deprivation would have started in a few minutes once under. It was lit by a candle inside the hull but this was extinguished at some point when operating.
It was a literal death trap, as noted above two crews died in trial. Per recollection there may have been some primitive chemical provision for oxygen or removal of Co2.
The ship was never intended to be under very long, a half hour at most if even that. Basically, surface approach and then dive for final approach to target.
Yes! It was for sure extremely uncomfortable. As I mentioned elsewhere, the recovered skeletal remains of some of the crewmembers showed changes to their shoulders and arms from spending so much time hunched over and cranking. They practiced a lot, and I think that speaks to how much they had to contort themselves when doing so.
I'm not aware of any CO2 removal or oxygen, but they did have a rudimentary snorkel system powered by bellows. However, historical records indicate that it wasn't very useful. I did the math of how much gas flow it could provide, and the math agrees with the records, as it showed that it did not provide enough air circulation to give them a lot of extra time. They were by far best off surfacing and opening the hatches, and this is a big part of why they did most of the cranking on the surface of the water.
While closed up, their gas supply depends on a bit on work rate, but per my math they would have been uncomfortable and wanted to refresh their air between 17 and 33 minutes.
The water temperature outside of Charleston in February is an average of 50 degrees F (10 C for our metric friends). The winter of 1864 was described as colder than usual, so it's a safe bet the water was at that average or below. At the work rates likely used by the crew (which I based off of rates of oxygen consumption that would have been sustainable for them for the length of time they needed to crank), the space inside the hull, and the hull material, their internal temperature would have gotten up to a maximum of 69 degrees F (20.6 C) at their heaviest work rate. Sooooo.... I think it was cold. Especially because they would have been somewhat pressed against the metal hull, which would have been at about the 50 degrees F of the water.
One crew member had a US Navy peacoat, a garment famous for its warmth in humid ocean air. However, because of the decomposition of the crew remains and the coat fabric, it's not clear if he was wearing it or sitting on it as a cushion. It's possible he did either or both, but if using it as a cushion, I would suggest there would be better things to bring for that purpose.
Since they were 1) in the ocean and 2) working hard meaning they were exhaling a lot of moisture, and they have poor gas circulation with the outside, the humidity level inside the sub would have been at maximum. I bet it was downright clammy as heck. Their supply of fresh air came from the fore and aft conning tower hatches, which were ovals. You can see a marvelous reconstruction here at a site called the Vernian Era, maintained by a man named Michael Crisafulli (full disclosure he and I are internet friends through Hunley love). It's evident that these small hatches were not providing tons of gas exchange, so I think it would have felt stuffy inside too.
It's hard to determine exactly how long they were in there for, but it could be hours at a time. As far as I know, there is no record of their exact bathroom plans, but there was a wooden bucket found inside the boat.
I only hope they dumped it out the hatches after enough uses.
What a great experiment! You used piezo pressure sensors and amplifiers designed for measuring such explosions, with foam-covered cables and a low-pass filter to block any signals above 40 Hz. Was there an issue with the cables themselves possibly being microphonic, and potentially messing with your data?
Yes! Tourmaline! I may or may not have subsequently purchased myself tourmaline earrings in a nod to my highest-performing pressure sensors. Bwahahah. One fix: it was a high-pass filter.
I did not notice any issues with the cables being microphonic, and I think that's for two reasons. 1) We were looking at EXTREMELY high frequencies. With blasts, pretty much all the fun is done and over within the first 10 milliseconds, in this case like the first 100 milliseconds, and even within that we were focused on the highest-frequency components as those are the most injurious. That made signal processing a bit easier, tbh, we did not need to do much processing. 2) We were in the middle of nowhere. Seriously, a pond on the back edge of a literal working farm. We had to drive to the farmer's house, it was maybe a mile or so away. That means very little signal interference! I was powering everything off deep cycle marine batteries, which I would swap out when needed and recharge overnight. I did use a small generator with a signal conditioner for the most power-hungry element (the acquisition box), but even that was at the far end of the dock, in the opposite direction as the cables.
My biggest issue was signal loss into the water before I wrapped the cables in foam. Grrrrrrrr that one annoyed me.
There was! It as a fairly advanced setup. The hand crank had handles that were both offset and staggered, like a modern-day crankshaft. This design ensured that the crewmembers were always at different points in their crank cycle, which would have helped smooth out the force being delivered (as opposed to everyone pushing at once and pulling at once, which would have been jerkier). The end of the crankshaft was equipped with a gear system, and even a flywheel to help store energy and further smooth out that force transmission.
It would have been a heck of a workout. The remains of the crews showed changes to the bones of their arms and shoulders that seem to have been from so much time practicing.
Well, first, it would be fun to build a full-sized Hunley with a full-sized torpedo and set that nonsense off. Let's not pretend we don't all want to push the "go" button on that experiment.
But thinking even bigger.... I'd love to build full-sized models of multiple theories for how the pyramids could have been built and then test them using (well-paid) work crews. See what makes the most sense.
The fact that the first two crews of the Hunley died while in port should tell you something. In one case they simply forgot to close the hatch before diving. Similar fate for the other one as I recall, including the designer of the ship.
Incredibly brave or stupid take your pick. I go with brave, this is one of the iconic stories of American history. These guys ignored the stupid in favor of bravery.
The Hunley is available to view in Charlestown and if you get the chance go see it.
Yes! Wild times. The first crew died because they had the hatches open while under tow, meaning they were being towed by a larger ship. Understandable, since hand-cranking a submarine is real hard, and the air supply inside would have been stale. But a wave swamped the open forward hatch, the bow started to go down, and only 3 escaped in time.
The second time, you are correct, Horace Hunley himself decided to go for a joy ride and plowed it into the ocean floor. He and the crew were unable to get it out. It was.... not a good death.
I've thought a lot about why a third crew was willing to go, and I think honestly at that point there was bravery and desperation mixed together. Lieutenant George Dixon, the pilot on the sub's fateful final mission, left behind letters to loved ones before his last night, and in them he spoke at length about hungry they all were from the shortages of the extreme war.
Edit: I wrote 5 escaped, but 3 escaped and 5 died. Fixed.
To what extent were the crew “still at their stations”? I recall reading about this not too long ago and was curious as to what the condition of the vessel was when she was found and raised. Was it as simple as the concussive force killing all of them instantly or rendering them unconscious?
I made you an image post here, because I think the way Lt Dixon's remains in particular sat slumped is particularly remarkable.
The Friends of the Hunley has willingly released the positions of the crewmembers in positions 3-8 and, while their soft tissues decomposed quickly leading to their skeletal remains tumbling into the bilge area, the skeletal remains are fairly well-sorted with each one at his battle station. Dixon was the first encased in silt, as the first traces of silt came in early through the unlocked fore conning tower, which is why his lower body and arms were thought to have been locked in place.
As you can see, he in particular seems to have just... sat on his tiny little pilot bench... and died.
Fun fact, none of the images in the Hunley museum show the remains of Dixon or the guy at the #2 spot. That's theorized to be because the #2 guy is a little more strewn out from his position, indicating he MAYBE was trying to crawl toward that fore hatch and freedom. But, at best, he was clawing his way there. To reconstruct these, a gentleman named Michael Crisafulli and I went through old videos where they showed the bone locations on screen during Hunley documentaries.
I was assigned this name by the good gentlemen of the podcast Ridiculous History, and immediately sworn to secrecy for the reasons upon penalty of death. Loose lips sink submarines!
OMG, I just read about your research. I have a couple of questions after reading your article. BTW, I don't understand the math, but assume it's all correct.
Am I correct that your conclusion is that the blast created a second shock wave inside the Hunley that disabled/killed the crew?
Didn't the Hunley pull the torpedo into the Housatonic? If that is the case, wouldn't the hull of the Housatonic provide a measure of protection from the blast wave? I did not see anything about that in the paper.
If I am correct about #1 above, why were WW2 submarine crews able to survive depth charges that exploded close to their subs?
I understand that there were folks that attacked your research when it was published. I am not one of them, just a guy who is very interested in the topic and curious.
OH dang I love that you assumed my math was correct, thank you. I do think it is. But I will never forget one notable email from a young man who read a piece I wrote for Smithsonian Magazine on the topic and emailed me offering to "help" me with the math because "blast physics is hard." I was nice. I sent him back the academic paper. He said something like oh it looks like you have it handled.... now your actual questions!
Kind of! Since the explosive used was black powder, which is a low explosive rather than a high explosive, it does not make a proper shock wave. If you care about the differentiation, ask away and I'll clarify, but if you don't, let's just agree to call it a pressure wave instead, hooray! If you rephrase your question to say "pressure wave," then YES. :)
It did not. Earlier designs used a torpedo towed behind the Hunley on a long line, and those yes indeed pulled the torpedo against the target's hull. However this design led to frequent issues like the line getting tangled in the sub's propeller, which is bad for obvious reasons. So for the final, high-stakes attack, they simplified it, and just put the bomb on the end of a 16-foot pokin' stick attached to the bow of their sub.
Ohhhhhh I love this question and I asked myself the same one. I did do actual math here to assess that scenario, but that's like... a whole other comment of talking, so I'll wait for someone to ask for it before offering. The short version is that by WW2 submarines had been redesigned to 1) go to much deeper depths and 2) be more robust to getting hit by stuff in transit. Part 1 means that the hulls were thicker and made of more robust materials, which also made them more robust against the type of deflection needed to transmit the pressure waves to the inside. Part 2 means that the subs were build with a double-hull design, meaning there was a second layer to the hull to protect the pressure-proof layer against getting hit with stuff and thereby getting damaged. This second layer would help absorb some of the blast force.
Per my numbers, these two elements reduced the transmission of pressure into the crew compartment by quite a lot. So little would have gotten in that the submarine would have experienced structural damage and sank by the time the crews would have been at risk of the same types of blast injuries. And by that point... yeah maybe they got blast lung... but they were inside a rapidly sinking broken submarine too, so their odds weren't great.
There's sadly not a ton of information about the USS Alligator! Record-keeping fell to the wayside during the shortages of war, and that was especially true for projects that would have been considered secret. The US Naval Institute wrote a great and comprehensive piece about what we do know.
Your research indicates that earlier runs with other submarines had successful results, and that the combination of a changing to a wrought iron hull, putting the sub deeper in the water, lowering the torpedo, and shortening the spar jointly led to the deaths of the crew.
With this in mind, what do you think is the simplest/most likely “road not taken” design/process change that would have saved the crew, while preserving the effectiveness of the submarine as a warship?
Oh this question haunts my dreams. You are correct that almost any change at all would have been likely to reduce the blast transmission enough to save the lives of the crew. Possible changes meaning longer spar, riding higher in the water, etc. However quick note, the hull was always wrought iron.
I think the easiest change to make would have been raising the level of the torpedo in the water. Per my experiments, where I did extensively look at transmission through various sections of the hull, there was remarkably little pressure wave coming in through the bow. I think that was a combination of its pointed shape and the water-containing ballast tank in there. They lowered the torpedo to get it beneath the USS Housatonic, as per the correct advice of their bomb experts, getting the torpedo lower in the water and beneath the enemy ship would create the most destructive force. We know this to be true! But their bomb was more than sufficient to sink the Housatonic, so if they'd attacked with it at the waterline, they likely still would have been successful while also surviving.
It was confirmed that the gold coin found with Dixon's remains took a bullet while in his pocket at the Battle of Shiloh, and almost certainly saved his life!! (note: Civil War medicine was not great, especially in the field, so a bullet to the femur was likely to cause death even though now it can be survivable) However, there are no contemporary records linking the coin to his supposed sweetheart, Queenie Bennett. The records indicating it came from her appear after Dixon's death. That plus her age (I think 13? Fact-check that number) at the time of his departure for war, and her financial status make a lot of people including me skeptical of that origin story.
But life-saving gold coin with a dent in it!!!!!! C'moooooon, that's cool enough for me!
Thank you for answering! Ive read a few books on the American Civil War and yes, those wounds were brutal, totally lucky he survived! Those slugs they were shooting were horrific.
As for the solution... I am not involved in the preservation so I'm hesitant to present myself as an authority on that. My understanding, though, is that it's a chemically basic solution, which would help reverse any corrosion processes. (again, fact check this, this is not my area)
Bomb the size of a beer keg + 16 foot poking stick = bad news
The submarine sank because the crew was already dead from the blast, and it just floated away!
How I figured it out is a much longer and more involved story, but the TLDR is I built a scale model of the submarine and its torpedo, and coupled that with some advanced computational modeling, as well as a thorough analysis of the other plausible theories through physics and shootin' stuff. Once I had eliminated the other theories, it was time to set off some explosives (legally and with proper safety, the ATF helped).
You can actually use scale models to study explosions and their effects, within certain reasonable limits. So me, with a 6.5' scale model in a pond, along with some qualified-expert friends and some nifty blast gauges, and we looked at the effects the bomb would have on the crew inside.
If you'd like more, there is a book excerpt freely available here thanks to Smithsonian Magazine!
I was surprised by how much information various researchers had found as a group about the crewmembers, both of the final mission and the missions before. For example, one of the crewmembers was known in the documents only as JF Larsen. Based on the spelling of the last name, however, and the fact that he was known to have been an immigrant, he was traced to Denmark. The archivist at their national archives, a man named Adam Jon Kronegh, had in his spare time chipped his way through the records they had that might contain him. He actually found Larsen! He identified his full name as Johan Frederick Larsen, born April 9, 1841, and then was able to fill in many of the gaps surrounding Larsen's life and story, and how he ended up inside a Confederate submarine.
As people shared this type of information with me and I was able to do more archival research to find more myself, I was surprised by how rich and complete the people in the boat started to feel. Some of them left behind evidence of their reasons for being there, and none of them said a word about slavery. Most were substitutes, paid to take the place of wealthier Southerners who did not want to fight. Most were immigrants! Lieutenant Dixon left behind letters, he did not talk about slavery, he talked about trying to get food for his family and people.
Building them as people changed my perspective and reinforced that it's ok to hate the politicians, their racism, and the war they started over it, but it's not always correct to assume that's why each individual person got thrown into the war too.
WannaBMonkey | 10 days ago
I learned it school that it sank from the blast of its own torpedo. I haven’t kept up to date with new civil war discoveries so can you elaborate on the series of events?
[OP] BombNerd | 9 days ago
TLDR: Bomb the size of a beer keg + 16 foot poking stick = bad for your health
It had a spar that was 16 feet long, and at the end of that spar was attached a bomb made out of thick welded copper and containing black powder. Historical records vary, but imo the most robust records indicate it had 200 pounds of black powder inside (91 kg). That would have made it about the size of a beer keg!
On February 17, 1864 the crew of eight cranked the HL Hunley up to the side of the Union ship USS Housatonic, which was part of the blockade outside of Charleston Harbor. The bomb - called a torpedo, which meant a stationary explosive at the time - had pressure triggers, and once those little horns pressed against the Housatonic's hull, the bomb went off.
The submarine was recovered in 2000 and raised, but when it was opened as part of the conservation efforts, the skeletal remains of the crewmembers were found still seated at their battle stations. In previous sinkings, they had been found trying to escape through the fore and aft hatches. This time, in contrast, it seems they just sat down and died.
Theories have abounded ever since, with the oddity of the crew positions fueling passion for this apparent mystery. For me, as a blast specialist, those were all the hallmarks of blast trauma. However, in science, if you don't have data, you're just speculating, and so it was then a mission to get data to assess the plausibility. Also to explain HOW. If the hull of the boat was intact, HOW did they die of the blast? And how do we explain the other quirks of the historical records, like the blue light?
The rest is blast physics! And honestly probably too much for a comment-level explanation. I did write a book about the story where there is a whole chapter about blast trauma, but I'm trying to stick to the subreddit rules and not self-promote and instead just enjoy this history nerd moment together. So, if you want a free version, the book is heavily excerpted in this piece for Smithsonian Magazine, and that includes more details on the blast-level explanation.
Cheers!
FibonacciSpiralOut | 9 days ago
Pretty sure her research is actually what provided the hard proof for that theory. Definitly curious to hear the exact breakdown of the timeline though.
[OP] BombNerd | 9 days ago
It is! I've got DATA, y'all.
Can you clarify which timeline you mean? Happy to answer.
RacingEnzo | 10 days ago
Hi Rachel. Knew you when we hired you at Panama City. Which did you enjoy more, investigating the disappearance, or blowing up a scale model?
[OP] BombNerd | 9 days ago
Oh, hi!! It's not clear who you are from your profile (sorry), but do DM if you'd like to say hi. Pass my hello back to everyone in Panama City too, please. Dang do I miss the diving there.
I think this will surprise everyone, but I enjoyed investigating the disappearance more, because I was doing that in archives with HVAC and chairs. The scale model work was thrilling when the live charges and gauges all started working in concert and we got results, but there was quite a bit of trial and error before that. Despite having access to serious experts in both fields (I collaborated with my ATF agent, who knew a ton about black powder, an Army EOD guy with tours dismantling IEDs in Iraq, and fellow US Navy civil servants who built and used the gauges), there were just a lot of things about these experiments that were combinations of things nobody had done before or in a very long time. SHOCKINGLY, I could not find anyone else alive who had built Confederate black powder submarine torpedoes before, I KNOW RIGHT!!!
Then of course there was the weather. We were very exposed to the elements, and a lot of the days were rough.
So, yes, there were some absolute high points in the experiments, and I will remember them forever with a smile. But overall, like with most science there was a lot of failure before there was success. The archives, however, were always guaranteed to have old papers. And chairs.
RacingEnzo | 9 days ago
We are anonymous here on Reddit, but here is a hint. Go Blue!
bravohotelechomike | 10 days ago
In Afghanistan whenever we would hit an IED one of the biggest things we learned to worry about was the proximity to the blast radius. It was making our folks’ lungs unable to process air due to pressure damage. Even a few meters of distance could be the difference between life or slow death. How much did that play a role here or were they just knocked unconscious?
[OP] BombNerd | 9 days ago
Yes, absolutely. That was my leading theory of what happened to the crew. There's a lot more detail in the book In the Waves, where I do go into examples from Iraq and Afghanistan and even one wild experiment where they showed blast transmission into armored vehicles (not at fatal or injurious levels, but still, DANG). That being said, it seems like you're thinking exactly like I was, which is:
Bomb the size of a beer keg + 16 foot poking stick = bad news
With blast, it's unlikely that someone is knocked unconscious without also experiencing lung damage, unless their lungs are somehow protected. Modern bulletproof vests do a magnificent job of protecting the lungs from blast, which is the evidence-backed theory of why Iraq and Afghanistan were the first wars where we started seeing such large numbers of TBI. The "glass half empty" perspective of blast-induced TBI is that those are people who probably would have been dead without modern lung protection. However, as you've pointed out, they're not perfect, and if someone isn't wearing a vest, then lung damage happens pretty readily, and I personally think that's what killed the crew.
On top of that, the brains of some of the crewmembers were present upon recovery. They show extreme changes from being in saltwater for 150 years, but they also show dark stains on their surfaces consistent with blood. A stain of blood on the surface of the brain is what fatal TBI from blast looks like. The Friends of the Hunley have never permitted the release of the MRIs, but they show them onscreen during a National Geographic documentary. I've added a screen grab to the images of the crew remains here.
There was also a theory that the bomb caused the sub to buck and heave in such a way that the crewmembers were knocked unconscious from the blunt force trauma of hitting their heads on the hull. While I think this is an interesting theory, there's only a narrow window of force between where you get knocked unconscious and where you have skull fracture, and the odds of eight people being hit in the head with that same level are very very small. None of the skulls showed any signs of blunt force trauma. Blast, in contrast, does not leave a mark on the skeletal remains including the skulls (below the levels where you get tissue disruption, of course).
bravohotelechomike | 9 days ago
Was it possible to determine if their ear drums were ruptured from their remains? If brain tissue was still intact then ear drums might also have survived. Bleeding from the ears was a strong indicator of distance from detonation for us.
[OP] BombNerd | 9 days ago
Sadly, no. You're correct that it would have been a "smoking eardrum" of sorts, but that tissue was long gone.
namastexinxbed | 10 days ago
I’ve read both of your books! What do you think of Project Azorian and the difficulty of raising K-129, would we have an easier time now with improved understanding or are the problems intractable?
[OP] BombNerd | 9 days ago
THANK YOU!!! I'm so excited you've read my books and (hopefully) liked them!
Ohhhhh the K-129, I love it so hard. To be honest, I think the biggest problems with a scenario like that is that the ocean has tricks up her sleeve and it is impossible to predict them until the day you try. With a wreck, too, there are almost always unanticipated aspects of position, damage, etc. You can't count on the hulls to be as intact as they were in the moments before the sinking, you don't know if you can count on them to hold while you try to raise it.
It's just a tough question for any engineering problem, to be able to anticipate and plan for all of the possibilities before you're even onsite.
But hey, you fund it, we'll try. :)
Opt4Deck | 10 days ago
Explosion! 💥
Based on your experiments, do you think the crew was aware of what was happening in their final moments, or would the blast have incapacitated them instantly?
[OP] BombNerd | 9 days ago
I don't think they were aware. I think they knew they were getting close to the USS Housatonic and then.... lights out.
There is a non-zero chance for each crew member that they survived. When you apply that to eight people, it is possible one of them survived the blast but had only severe lung damage. There was an extremely high chance of severe lung damage, so it's unlikely any survived without at least that. I think this little trick of statistics is extra fascinating when you compile it with the fact that the skeletal remains of the crewman at the #2 spot looks like he may have been trying to claw his way toward the fore hatch. It's not confirmed, of course, he could have just toppled off his bench that way too.
But can you imagine? Your bomb goes off, you have long enough to think YES WE DID IT, then with your next breath you feel like you're choking, you gag and see blood spray when you cough. You look around and all your crewmates are dead. The forward hatch is open, if only you can reach it... just maybe....
juanmlm | 10 days ago
How long would the stick carrying the charge would have to be for it to be survivable?
[OP] BombNerd | 9 days ago
GREAT QUESTION! I saw this question yesterday and tried to find my old spreadsheet where I did the math after asking it myself. I am sad to report that I failed, as it was two computers ago (it's somewhere, just amongst all the backups).
However, by memory, I believe it was 22 feet. It was not necessarily the increase in length that would have saved them, though, but the change in the angle between the boat and the bomb. By having a slightly longer spar, that angle changed, and more of the blast would have been directed at the bow of the submarine. Per my experiments, the bow did not transmit very much blast, which makes sense because of its sharp angle and the fact that there is a water-filled ballast tank with layers of other material types between the bow and the crew (going through various layers of things usually has a reductive effect).
They were so close to making it. They just needed a bit more blast physics.
Fun fact, the Confederacy's official bomb expert, a man named Gabriel Rains, strongly recommended a longer spar. He even made drawings of one, where he included changing that angle between the bomb and the boat to put them more on an even level and have the bomb in front of the bow. Always listen to your explosives experts, kids.
BearWithTopHat | 10 days ago
Might be dumb questions: What would have caused them to go through hypercapnia before hypoxia? In flight school we're taught quite a lot about the dangers of hypoxia, but I'm not sure I've even heard of hypercapnia before.
From reading through what I've got access to, your research suggests that their torpedo exploded off their bow, the shockwave propagated through the sub, and killed or incapacitated all crew members at their posts, allowing the ship to slowly drift and sink.
Is there any way to find evidence of that on the ship? I would think there would be some sort of deformation or cracks near the explosion which could concretely prove your theory.
[OP] BombNerd | 9 days ago
Not dumb questions at all!!! Very good questions, I in fact love the first one.
In flight school you were trained heavily on hypoxia because you're getting supplemental oxygen, and one of the biggest risks to aviators is that oxygen system failing and you slowly passing out. The Air Force did some nifty research showing that pilots who had been put through actual hypoxia experiences in a training environment had a 94% chance of recognizing that they were becoming hypoxic, whereas pilots who had only been told verbally about the symptoms but not experienced the physical hypoxia had a much lower chance of recognizing it during an actual emergency (I *think* it was only 6% but that seems to add up to 100% too neatly so I'm not going to trust my brain on this one. It was definitely below 25% though, so it was a big difference). Training for hypoxia has been the gold standard ever since!
Fun sidebar: when the SpaceX crew came to Duke for hypoxia and hypercapnia training, I was one of the inside tenders in the chamber for their altitude excursion, which means I was the one taking away and returning their oxygen masks and monitoring them during their period of lack of oxygen. Since the pilot was a billionaire, this means that I technically and truthfully get to say that I once suffocated a billionaire!
Inside any closed space hypercapnia will be a problem first because the people are breathing out the carbon dioxide into the space then rebreathing, whereas with aviation it gets released peacefully out into the world around you while your mask gives you more fresh O2. It's that effect of trapping the CO2 that makes hypercapnia an issue in enclosed spaces.
Hypercapnia becomes an issue first just because of the levels at which our bodies are sensitive to CO2 and O2. There's probably some evolutionary biology reason the levels are where they are, but that would require more thought, on a level that would require me to refill my snack supplies.
[OP] BombNerd | 9 days ago
Second question: sadly, no, there is no way to find evidence of that on the ship.
There is of course a higher level of blast overpressure that will force the hull of the ship to flex inward in a way that permanently deforms the hull, but it's at a much higher level. I do have a picture somewhere of a WWII experiment with a mini-sub where they achieved this level of hull deflection and it's very neat, but I'm not finding it on quick search so I'll loop back and add it as an edit if I can dig it up.
Quick note: since it was black powder, it was not technically a shock wave, it was just a "pressure wave." Poor little black powder, so maligned as a little "low explosive" instead of a "high explosive." Otherwise you nailed it.
[OP] BombNerd | 9 days ago
I FOUND THE PHOTOS.
These photos show the results of underwater explosives against the hull of WWII X-craft, which were mini-subs built by the British during WWII. The later two photos show the damage done by underwater explosives against an X-craft used in combat, and obviously it was sunk. In both cases, the mini-subs were exposed to much higher pressure levels than the HL Hunley experienced, and from high explosives, which are more damaging. That's why, for these, that type of distortion of the hull was permanent. In the case of the Hunley, it was temporary and thus left no trace.
Yes, the blast physics has been done to know where the various thresholds are between "no hull flexion," "temporary hull flexion," "permanent hull flexion," and "tearing the hull apart," and the range of force where you can get temporary hull flexion of the type that would transmit the pressure inside to the crew without leaving a mark is quite large for the design of the Hunley. (wonderful paper by a blast physicist named Michele Hoo Fatt)
In our case, however, it's sad that no permanent damage occurred, as that would be nice supporting evidence, wouldn't it?
Wash_zoe_mal | 10 days ago
So I understand how bioengineering covers this field of study, but how did you end up studying the submarine explosion?
Are you continuing with this subject or do you have new research you're moving into?
[OP] BombNerd | 9 days ago
I was working as a civil servant for the US Navy for several years before going back to grad school, and I actually continued my navy employment during my time as a grad student, so I was making routine trips back to my base and was heavily mentally aware of the problems facing warfighters. Specifically, traumatic brain injury (TBI). When I started grad school I was actually studying a different topic but it involved almost entirely coding, which I respect and do sometimes, but was not working for me as an "all day every day" type of thing.
Down the hall was another lab that I hadn't known about before, and they were working on injury biomechanics, which is the use of engineering principles to study the physiology of injuries. A lot of people in that field work on car crashes, as did half of that lab, but the other half studied TBI. Since I was already heavily studied-up on respiratory physiology because of my previous work, and blast trauma involves lung damage first and easiest, it was a natural bit of overlap. I wandered down and asked if I could switch labs, and since I was funded by a navy scholarship, I was able to!
I started my PhD simply investigating blast trauma patterns from underwater explosions, kind of the nexus of my previous areas of expertise. I wrote a few papers on that, but one day my advisor asked me if I could apply the same principles to investigating the HL Hunley. I did not know what those words meant, but when he left my office I started googling. And the rest is r/history!
[OP] BombNerd | 9 days ago
Oh you asked a second question didn't you. I'm always somewhat involved in the world of underwater blast trauma as there are a lot of open questions in that area. Right now I'm in the middle of a year-long sabbatical from hard science, but that's up in July. I cover other areas of underwater physiology as well, and have been slowly compiling historical data from a few topics in that world that I want to put together and analyze. Yes.... I am bad at "sabbatical"-ing.
ManintheGyre | 10 days ago
Can you describe the working conditions of the sailors inside the Hunley? How uncomfortable was it? Temperature, humidity, fresh oxygen? How cramped and for how long at a time? How did they go to the bathroom?
EnvironmentalWin1277 | 10 days ago
Extremely uncomfortable, no chance of escape if it went down. Cramped and oxygen deprivation would have started in a few minutes once under. It was lit by a candle inside the hull but this was extinguished at some point when operating.
It was a literal death trap, as noted above two crews died in trial. Per recollection there may have been some primitive chemical provision for oxygen or removal of Co2.
The ship was never intended to be under very long, a half hour at most if even that. Basically, surface approach and then dive for final approach to target.
[OP] BombNerd | 9 days ago
Yes! It was for sure extremely uncomfortable. As I mentioned elsewhere, the recovered skeletal remains of some of the crewmembers showed changes to their shoulders and arms from spending so much time hunched over and cranking. They practiced a lot, and I think that speaks to how much they had to contort themselves when doing so.
I'm not aware of any CO2 removal or oxygen, but they did have a rudimentary snorkel system powered by bellows. However, historical records indicate that it wasn't very useful. I did the math of how much gas flow it could provide, and the math agrees with the records, as it showed that it did not provide enough air circulation to give them a lot of extra time. They were by far best off surfacing and opening the hatches, and this is a big part of why they did most of the cranking on the surface of the water.
While closed up, their gas supply depends on a bit on work rate, but per my math they would have been uncomfortable and wanted to refresh their air between 17 and 33 minutes.
[OP] BombNerd | 9 days ago
Yes I actually did this math!!
The water temperature outside of Charleston in February is an average of 50 degrees F (10 C for our metric friends). The winter of 1864 was described as colder than usual, so it's a safe bet the water was at that average or below. At the work rates likely used by the crew (which I based off of rates of oxygen consumption that would have been sustainable for them for the length of time they needed to crank), the space inside the hull, and the hull material, their internal temperature would have gotten up to a maximum of 69 degrees F (20.6 C) at their heaviest work rate. Sooooo.... I think it was cold. Especially because they would have been somewhat pressed against the metal hull, which would have been at about the 50 degrees F of the water.
One crew member had a US Navy peacoat, a garment famous for its warmth in humid ocean air. However, because of the decomposition of the crew remains and the coat fabric, it's not clear if he was wearing it or sitting on it as a cushion. It's possible he did either or both, but if using it as a cushion, I would suggest there would be better things to bring for that purpose.
Since they were 1) in the ocean and 2) working hard meaning they were exhaling a lot of moisture, and they have poor gas circulation with the outside, the humidity level inside the sub would have been at maximum. I bet it was downright clammy as heck. Their supply of fresh air came from the fore and aft conning tower hatches, which were ovals. You can see a marvelous reconstruction here at a site called the Vernian Era, maintained by a man named Michael Crisafulli (full disclosure he and I are internet friends through Hunley love). It's evident that these small hatches were not providing tons of gas exchange, so I think it would have felt stuffy inside too.
It's hard to determine exactly how long they were in there for, but it could be hours at a time. As far as I know, there is no record of their exact bathroom plans, but there was a wooden bucket found inside the boat.
I only hope they dumped it out the hatches after enough uses.
jbtank | 10 days ago
Loved your book on this Dr Lance!
[OP] BombNerd | 9 days ago
Thank you!!! <3 Look at you all reading and stuff.
Aquaman258 | 10 days ago
Proud to have your books in Seaholm's library!
[OP] BombNerd | 9 days ago
Go Maples! :)
Bodark43 | 10 days ago
What a great experiment! You used piezo pressure sensors and amplifiers designed for measuring such explosions, with foam-covered cables and a low-pass filter to block any signals above 40 Hz. Was there an issue with the cables themselves possibly being microphonic, and potentially messing with your data?
[OP] BombNerd | 9 days ago
Yes! Tourmaline! I may or may not have subsequently purchased myself tourmaline earrings in a nod to my highest-performing pressure sensors. Bwahahah. One fix: it was a high-pass filter.
I did not notice any issues with the cables being microphonic, and I think that's for two reasons. 1) We were looking at EXTREMELY high frequencies. With blasts, pretty much all the fun is done and over within the first 10 milliseconds, in this case like the first 100 milliseconds, and even within that we were focused on the highest-frequency components as those are the most injurious. That made signal processing a bit easier, tbh, we did not need to do much processing. 2) We were in the middle of nowhere. Seriously, a pond on the back edge of a literal working farm. We had to drive to the farmer's house, it was maybe a mile or so away. That means very little signal interference! I was powering everything off deep cycle marine batteries, which I would swap out when needed and recharge overnight. I did use a small generator with a signal conditioner for the most power-hungry element (the acquisition box), but even that was at the far end of the dock, in the opposite direction as the cables.
My biggest issue was signal loss into the water before I wrapped the cables in foam. Grrrrrrrr that one annoyed me.
razak99 | 10 days ago
Was there a gear reduction on the hand operated propeller?
razak99 | 10 days ago
Would it have been difficult to move from their stations?
[OP] BombNerd | 9 days ago
There was! It as a fairly advanced setup. The hand crank had handles that were both offset and staggered, like a modern-day crankshaft. This design ensured that the crewmembers were always at different points in their crank cycle, which would have helped smooth out the force being delivered (as opposed to everyone pushing at once and pulling at once, which would have been jerkier). The end of the crankshaft was equipped with a gear system, and even a flywheel to help store energy and further smooth out that force transmission.
You can see a reconstruction of the gearing system here.
It would have been a heck of a workout. The remains of the crews showed changes to the bones of their arms and shoulders that seem to have been from so much time practicing.
Edit: typo, and to add link
badwhiskey63 | 10 days ago
I was just reading an article about your investigation! What historical event would you like to investigate if budget was not an issue?
[OP] BombNerd | 9 days ago
Unlimited budget, you say?????
Well, first, it would be fun to build a full-sized Hunley with a full-sized torpedo and set that nonsense off. Let's not pretend we don't all want to push the "go" button on that experiment.
But thinking even bigger.... I'd love to build full-sized models of multiple theories for how the pyramids could have been built and then test them using (well-paid) work crews. See what makes the most sense.
EnvironmentalWin1277 | 10 days ago
The fact that the first two crews of the Hunley died while in port should tell you something. In one case they simply forgot to close the hatch before diving. Similar fate for the other one as I recall, including the designer of the ship.
Incredibly brave or stupid take your pick. I go with brave, this is one of the iconic stories of American history. These guys ignored the stupid in favor of bravery.
The Hunley is available to view in Charlestown and if you get the chance go see it.
[OP] BombNerd | 9 days ago
Yes! Wild times. The first crew died because they had the hatches open while under tow, meaning they were being towed by a larger ship. Understandable, since hand-cranking a submarine is real hard, and the air supply inside would have been stale. But a wave swamped the open forward hatch, the bow started to go down, and only 3 escaped in time.
The second time, you are correct, Horace Hunley himself decided to go for a joy ride and plowed it into the ocean floor. He and the crew were unable to get it out. It was.... not a good death.
I've thought a lot about why a third crew was willing to go, and I think honestly at that point there was bravery and desperation mixed together. Lieutenant George Dixon, the pilot on the sub's fateful final mission, left behind letters to loved ones before his last night, and in them he spoke at length about hungry they all were from the shortages of the extreme war.
Edit: I wrote 5 escaped, but 3 escaped and 5 died. Fixed.
cferejohn | 10 days ago
Are you aware there is a recently published solo board game about Civil War submarines? It's called Infernal Machines.
[OP] BombNerd | 9 days ago
I AM NOT!!! But they will soon receive my money, thank you for telling me.
ItsSobee | 9 days ago
To what extent were the crew “still at their stations”? I recall reading about this not too long ago and was curious as to what the condition of the vessel was when she was found and raised. Was it as simple as the concussive force killing all of them instantly or rendering them unconscious?
[OP] BombNerd | 9 days ago
I made you an image post here, because I think the way Lt Dixon's remains in particular sat slumped is particularly remarkable.
The Friends of the Hunley has willingly released the positions of the crewmembers in positions 3-8 and, while their soft tissues decomposed quickly leading to their skeletal remains tumbling into the bilge area, the skeletal remains are fairly well-sorted with each one at his battle station. Dixon was the first encased in silt, as the first traces of silt came in early through the unlocked fore conning tower, which is why his lower body and arms were thought to have been locked in place.
As you can see, he in particular seems to have just... sat on his tiny little pilot bench... and died.
Fun fact, none of the images in the Hunley museum show the remains of Dixon or the guy at the #2 spot. That's theorized to be because the #2 guy is a little more strewn out from his position, indicating he MAYBE was trying to crawl toward that fore hatch and freedom. But, at best, he was clawing his way there. To reconstruct these, a gentleman named Michael Crisafulli and I went through old videos where they showed the bone locations on screen during Hunley documentaries.
Dense_Midnight8131 | 9 days ago
why are you called Big Spinach?
[OP] BombNerd | 9 days ago
I was assigned this name by the good gentlemen of the podcast Ridiculous History, and immediately sworn to secrecy for the reasons upon penalty of death. Loose lips sink submarines!
RL24 | 9 days ago
OMG, I just read about your research. I have a couple of questions after reading your article. BTW, I don't understand the math, but assume it's all correct.
I understand that there were folks that attacked your research when it was published. I am not one of them, just a guy who is very interested in the topic and curious.
[OP] BombNerd | 9 days ago
OH dang I love that you assumed my math was correct, thank you. I do think it is. But I will never forget one notable email from a young man who read a piece I wrote for Smithsonian Magazine on the topic and emailed me offering to "help" me with the math because "blast physics is hard." I was nice. I sent him back the academic paper. He said something like oh it looks like you have it handled.... now your actual questions!
Per my numbers, these two elements reduced the transmission of pressure into the crew compartment by quite a lot. So little would have gotten in that the submarine would have experienced structural damage and sank by the time the crews would have been at risk of the same types of blast injuries. And by that point... yeah maybe they got blast lung... but they were inside a rapidly sinking broken submarine too, so their odds weren't great.
Edit: typo
Dangerous-Bit-8308 | 10 days ago
Can you direct me to anything about the supposed US civil war subs, called Alligators? So far I've only ever heard mention of them from one museum.
[OP] BombNerd | 9 days ago
There's sadly not a ton of information about the USS Alligator! Record-keeping fell to the wayside during the shortages of war, and that was especially true for projects that would have been considered secret. The US Naval Institute wrote a great and comprehensive piece about what we do know.
CaesarSeizer | 10 days ago
Your research indicates that earlier runs with other submarines had successful results, and that the combination of a changing to a wrought iron hull, putting the sub deeper in the water, lowering the torpedo, and shortening the spar jointly led to the deaths of the crew.
With this in mind, what do you think is the simplest/most likely “road not taken” design/process change that would have saved the crew, while preserving the effectiveness of the submarine as a warship?
[OP] BombNerd | 9 days ago
Oh this question haunts my dreams. You are correct that almost any change at all would have been likely to reduce the blast transmission enough to save the lives of the crew. Possible changes meaning longer spar, riding higher in the water, etc. However quick note, the hull was always wrought iron.
I think the easiest change to make would have been raising the level of the torpedo in the water. Per my experiments, where I did extensively look at transmission through various sections of the hull, there was remarkably little pressure wave coming in through the bow. I think that was a combination of its pointed shape and the water-containing ballast tank in there. They lowered the torpedo to get it beneath the USS Housatonic, as per the correct advice of their bomb experts, getting the torpedo lower in the water and beneath the enemy ship would create the most destructive force. We know this to be true! But their bomb was more than sufficient to sink the Housatonic, so if they'd attacked with it at the waterline, they likely still would have been successful while also surviving.
Fall_Harvest | 10 days ago
Was the $20 gold piece found near Lt Dixon ever confirmed to have been given to him from his sweetheart or is that still a legend?
Also, if I may, what solution do they use to keep the ship stable in its tank and not further corrode?
[OP] BombNerd | 9 days ago
It was confirmed that the gold coin found with Dixon's remains took a bullet while in his pocket at the Battle of Shiloh, and almost certainly saved his life!! (note: Civil War medicine was not great, especially in the field, so a bullet to the femur was likely to cause death even though now it can be survivable) However, there are no contemporary records linking the coin to his supposed sweetheart, Queenie Bennett. The records indicating it came from her appear after Dixon's death. That plus her age (I think 13? Fact-check that number) at the time of his departure for war, and her financial status make a lot of people including me skeptical of that origin story.
But life-saving gold coin with a dent in it!!!!!! C'moooooon, that's cool enough for me!
Fall_Harvest | 9 days ago
Thank you for answering! Ive read a few books on the American Civil War and yes, those wounds were brutal, totally lucky he survived! Those slugs they were shooting were horrific.
Thank you for the AMA its a fascinating read!
[OP] BombNerd | 9 days ago
As for the solution... I am not involved in the preservation so I'm hesitant to present myself as an authority on that. My understanding, though, is that it's a chemically basic solution, which would help reverse any corrosion processes. (again, fact check this, this is not my area)
VerySpicyLocusts | 9 days ago
Sooo what’s the secret?? How did the ship sink? And how did you figure it out?
[OP] BombNerd | 9 days ago
Bomb the size of a beer keg + 16 foot poking stick = bad news
The submarine sank because the crew was already dead from the blast, and it just floated away!
How I figured it out is a much longer and more involved story, but the TLDR is I built a scale model of the submarine and its torpedo, and coupled that with some advanced computational modeling, as well as a thorough analysis of the other plausible theories through physics and shootin' stuff. Once I had eliminated the other theories, it was time to set off some explosives (legally and with proper safety, the ATF helped).
You can actually use scale models to study explosions and their effects, within certain reasonable limits. So me, with a 6.5' scale model in a pond, along with some qualified-expert friends and some nifty blast gauges, and we looked at the effects the bomb would have on the crew inside.
If you'd like more, there is a book excerpt freely available here thanks to Smithsonian Magazine!
Edit: typo
bisque-brigadier | 9 days ago
What part of your research on the Hunley surprised you the most?
[OP] BombNerd | 9 days ago
I was surprised by how much information various researchers had found as a group about the crewmembers, both of the final mission and the missions before. For example, one of the crewmembers was known in the documents only as JF Larsen. Based on the spelling of the last name, however, and the fact that he was known to have been an immigrant, he was traced to Denmark. The archivist at their national archives, a man named Adam Jon Kronegh, had in his spare time chipped his way through the records they had that might contain him. He actually found Larsen! He identified his full name as Johan Frederick Larsen, born April 9, 1841, and then was able to fill in many of the gaps surrounding Larsen's life and story, and how he ended up inside a Confederate submarine.
As people shared this type of information with me and I was able to do more archival research to find more myself, I was surprised by how rich and complete the people in the boat started to feel. Some of them left behind evidence of their reasons for being there, and none of them said a word about slavery. Most were substitutes, paid to take the place of wealthier Southerners who did not want to fight. Most were immigrants! Lieutenant Dixon left behind letters, he did not talk about slavery, he talked about trying to get food for his family and people.
Building them as people changed my perspective and reinforced that it's ok to hate the politicians, their racism, and the war they started over it, but it's not always correct to assume that's why each individual person got thrown into the war too.