since i seem to be becoming a titanic guy, ive decided to just lean into it and explain the best i can, in laymans terms, what happened to titan and why the design had been criticised by experts in the deep-sea diving community.
i will preface this with the fact that im not an engineer. i have a psychology degree so this is not in my wheelhouse; im simply attempting to relay the information that has been made public in a more layman-friendly way. if i get anything wrong, please correct me.
a second preface is that quite a lot of this post is relying on oceanliner design’s video on this topic. though hes less critical of oceangate than i am, mike does a great job of breaking everything down so anyone can understand it. [any statements i make without listing a source are likely to be information from this video]
so with that out of the way, lets jump into it:
first, lets talk about what titan was. ive seen it described as a submarine by many people and im pretty sure ive also described it as such, but titan was a deep-sea submersible with a guiding philosophy of simplicity.
whats the difference between them?
submarines are self-independent vehicles meaning they do not rely on exterior support.
meanwhile, submersibles can submerge and can act independently to an extent, they primarily rely on exterior support such as being tethered to the mother-ship, or in titans case, receiving navigational inputs from said ship.
and here we meet our first bit of criticism; almost all other submersibles do not rely on external navigational inputs. they have their own equipment and systems for this. it may seem trivial, but as oceanographer peter girguis points out, these systems are as important for navigation as they are for the safety of the crew. [x]
when you are in water that deep, you need to know your exact position and be in constant contact with the mother ship. and its not as if oceangate did not have access to this technology, the beacons they use are commercially available. instead, they relied on short texts as a form of communication which is simply unacceptable. the submersible limiting factor has real-time verbal communication between those in the sub and those on the mother ship on dives 27,000 feet deeper than the titanic wreck.
“titan [did] not appear to have some of the other kinds of sensors, beacons and other systems that we use in research, that are also important just to maintain contact.”
“titan was not designed with research in mind.”
most deep-sea submersible designs are based around the design for the dsv alvin as it was one of the first of its kind. you might ask why its alvin that designs are based around and not another. well that would be because alvin was launched in 1964 and is still in use today and has completed over 5000 dives.
and this is why so many in the deep-sea submersible community are so outraged at titans design. titan was around 5 or 6 years old when it imploded; alvin is 59 this year. we have the technology to create submersibles like alvin or limiting factor that are arguably safer to be in than on the deck of a ship [x]; this disaster should never have fucking happened.
okay, so now lets move onto the actual design of titan which differs very much to most other deep-sea submersible and this is not a good thing. the reason most designs are so similar is because these features have been shown time and time again to be safe. again, ill refer to what peter girguis stated:
anyway, ill get back on topic. this is alvins design:
alvins pressure vessel is a large sphere with titanium walls that are 2 inches or 5cm thick. titanium is used as it is a very strong metal as whathisname from 2012 sang about, and a sphere is used because its the best shape for equally distributing pressure. when designing these vessels, you do not want any areas where pressure can build up and a sphere does not have any; the entire structure reinforces itself.
unlike literally every other deep-sea submersible, titans pressure vessel was not a sphere and not made of titanium, rather it was cylindrical with two hemisphere on either side and was built out of carbon fiber. see the shape below:
the important part is the big circle labelled “personal sphere”. this is called the pressure vessel and is where crew and any equipment needing protection from the water pressure reside. this vessel needs to be able to withstand around 6000 pounds or 3 tonnes of pressure per square inch, which is about 400 times the pressure on the surface.
if they had followed previous designs, they would have had to make a much larger sphere in order to fit everyone. but the bigger you make your sphere, the weaker it becomes so you then have to use thicker walls, and all of this makes the pressure vessel much heavier. and this is where youd run into problems because the submersible still needs to be able to plucked from the ocean at the end of the trip and to power itself in the water. the heavier it is, the harder this becomes.
first, well address the shape. as the design philosophy of titan was so that it could carry up to 6 passengers, it would have been very difficult for the pressure vessel to be shaped as a sphere. alvin, in comparison, can only fit three crew and equipment.
so instead, they chose a cylinder. this is not a terrible choice by itself. it is preferable to use round shapes in high-pressure environments as pressure builds up in corners, especially right angles. if youve ever wondered why plane windows have round corners, its because the square windows on the de havilland comet (the worlds first jetliner) gave areas where pressure could build up and caused the jet to suffer a series of explosive decompressions. it crashed many times. [x]
now, well get into where the design really has problems: the materials used. as i mentioned, the majority of the pressure vessel was made of carbon fiber. the ceo of oceangate, stockton rush, believed that carbon fiber would have a better strength-to-buoyancy ratio than titanium, and this was one reason why it was chosen. [x]
so in terms of shape, its not the worst choice. it is much preferable to use a sphere as a cylinder is not as adept at equally distributing pressure, but their choice was at least logical.
on the end of the cylinder, there were two titanium rings bonded to the carbon fiber hull (though the method of bonding is not publicly available), and these rings were then bolted to two titanium hemispheres. now, you might notice that titan does have four right angles in the pressure vessels, but these are within the vessel so as long as no pressure can get into vessel, these are fine.
the problem with this is that carbon fiber is an experimental material that has not been fully evaluated. stockton rush was very aware of this as he was repeatedly warned by many experts in the field, including deep-sea exploration specialist rob mccallum who stated that:
“that carbon fibre is not an acceptable material”
if this occurs, not only do the gaps give areas for pressure to build, the pressure vessel becomes much weaker, and runs the risk of failing as happened. this risk only gets worse when you decide to use expired carbon fiber.
now, you might be saying “kai, you literally told us earlier that they did use titanium” and if you are, A+ to you my friend, youve led us straight onto another problem with the design of the titan: using multiple materials.
one major concern about the carbon fiber for the hull is that it had to be layered up and cured in between until the hull was 12.7cm or 7 inches thick. these layers cause a problem that titanium does not have; there is a risk of de-lamination, aka the layers separating. as previously stated, the titan was several years old so it had already gone through many pressurisations and dive cycles which all run the risk of de-laminating the hull.
and this, ladies and gentleman and those of us past that stage, is why deep-sea submersibles use titanium not carbon fiber.
by designing titan like this, stockton rush strayed ridiculously far away from any other designs which have been tested and shown to work. the submersible was not safe to travel on, especially so far down to be able to visit the titanic wreck. as rob mccallum states:
you just dont do it. by introducing areas where multiple materials meet, you are introducing potential points of failure because well done, stockton, youve introduced yet another area where pressure can build up.
“[titan] was the only submersible in the world doing commercial work that was unclassed. it was not certified by an independent agency.”
in fact, it makes sense to go through the process because you then know that your vessel is safe and idk, its probably better for marketing if your vessel has been certified as safe.
mccallum goes on to describe stockton as a “maverick entrepreneur” who wanted to think outside of the box even when it comes to things like the rules of physics or tried and true engineering principles.
and im sure we can all guess why. it wouldnt have passed and the company has recognised that the design lays outside of the accepted system. though its not a mandatory process even though it really fucking should be, theres no reason to not let your vessels be examined by a marine organisation.
we know that the hull was breached. we know this as one of the very few safety features aboard titan was something known as a “real-time hull health monitoring system” or an rtm. [x]
and he is completely right because what happened to the titan showed how the design of it was so flawed. [x]
“if you steer away from sound engineering principles, which are all based on hard won experience, there is a price to pay, and its a terrible price”
this did what it said on the tin and it did before the catastrophic implosion of titan. when the rtm picked up on too much strain on the hull, it sounded an alarm as a warning. those on board were prepped so they knew what this meant so they used one of the other few safety features on the sub: dropping the ballasts.
ballasts are heavy material gathered in the bottom of a ship or vessel to help stabilise the ship. you use them in order to stop a ship from becoming top-heavy as a top-heavy ship is much more likely to capsize; see the ss principessa jolanda that sank at launch as she launched with all her fittings completed and empty ballasts, causing the center of gravity to be too high. some ships have port and starboard (left and right) water ballasts and if theyre listing dangerously to one side, they can release the water in that ballast to attempt to stabilise the ship.
this, again, is an area of criticism as most submersibles have multiple features that can be used in an emergency. marine geologist, chris goldfinger points out that most submersibles have multiple ways of self-rescue, such as detaching the pressure vessel from the sub itself. [x]
in the case of the titan, dropping the ballasts was the only way the ship could surface in an emergency. it appears that those on board attempted to do so, but did not surface quick enough to avoid catastrophe.
“[titan did not have] nearly that much redundancy and self-rescue capability."
“im concerned that they [oceangate] overlooked some of the features that we build into research submersibles, because they struck [the builders] as costly or unnecessary, or uninteresting. a lot of those features that we see across submersibles have evolved over decades, precisely because they work, and because we know it increases safety for the crew.”
"i have grown tired of industry players who try to use a safety argument to stop innovation"
hes also stated that titan was underprepared which most experts in the field agree with, such as girguis who stated that:
and we know that stockton rush was aware of all these issues; email exchanges show that people at the company came to him with concerns, but he brushed them away. instead, we have statements from him like:
he heard warnings from employees and from deep-sea submersible experts, and a former employee david lochridge alleged in a counterclaim lawsuit in 2018 that he was fired for raising concerns over quality control and testing of potential flaws. [x]
keep in mind that oceangate originally sued him for breach of contract because he brought all of his concerns to osha because he was that concerned. though, this was settled out of court, it clearly shows that this disaster was years in the making.
“it was only a matter of time before they killed somebody.”
45 Likes, 2 Comments - Rob McCallum (@rob_mccallum) on Instagram: “Some of the first boards I did on my then brand new just out iPad Pro early Dec 2015. About the 4th…”
New The Strain's Storyboard pic by the artist Rob McCallum on Instagram! (1/2)
This one is from the Episode 3 "First Born" from Season 3, when Mr. Quinlan decapited the Master and fell to the ground after being riddled with bullets. Poor Quinlan 😔
