#12. The Titan Disaster was Predictable, but …
In which the E@L argues that deep-sea submersibles still have an important role in research
(Another) Disaster at Sea
By now you have heard or read about the loss of a five-person tourist submersible called the Titan, that imploded during a dive to visit the Titanic shipwreck. Many people have speculated about the possible causes of this disaster, but few, if any, of those commentators have actually dived in similar submersibles. I have. In this missive, I aim to offer my own perspective on the tragedy.
In my career as a marine scientist, I have made over 60 dives in research submersibles (or rather, human-occupied vehicles, HOVs). I have made five dives (the deepest to 3700 m) in Alvin, the sub used by Bob Ballard to explore the Titanic, two in a similar sub called Pisces, and over fifty in a smaller sub called the Delta, most of which were less than 300 meters. (My E@L post #10 was written as a poetic description of a descent to the deep-sea floor in the Gulf of Alaska with Alvin.) Alvin has been completely rebuilt since I made my dives in it (in 1999 and 2002). In 2003 I provided NOAA’s input to the National Research Council Report, “Future Needs in Deep Submergence Science”, that supported replacing the original Alvin with an improved vehicle.
Voyage to Sea the Bottom
Alvin was built as a titanium sphere, about 7 feet in diameter. A sphere is very difficult to crush because the pressure is even at all points on its surface, whereas tubes are more prone to crushing because they are weaker in the center. The sphere was attached to a truck-like frame that held air and oxygen cylinders, batteries, thrusters, and buoyancy tanks as well as flotation in the form of blocks of glass micro-spheres, called syntactic foam. It was designed to be neutrally buoyant with passengers inside and was then ballasted by the addition of weights to the frame.
To descend, Alvin pumped water in or out of pressure tanks, which made it negatively buoyant. To ascend, it could drop the weights electronically. In an emergency, it could also drop the external manipulators, the science tray, and the batteries. The last-ditch method was to release a bolt attaching the sphere to the frame, which would then allow the sphere to float (or more likely, rocket) to the surface. I’m glad we never tried it.
GPS does not work underwater, so Alvin and virtually all other subs use a tracking system that consists of an external, battery-powered transponder that responds to a signal from the mothership. These systems cost a few thousand dollars and are cheap enough to install on remotely operated vehicles (ROVs) that cost less than $100K. The one exception was the Pisces, operated by the Canadian Navy; my dives were only a few hundred meters deep, so they tied a buoy to it, and had a watcher on the bridge of the support ship call out the range and distance to the buoy every few minutes. Primitive, but effective. (No jokes about Canada’s budget, please).
All of the subs I worked in had the ability to open and close the hatch from inside, which allowed the crew to escape from the sub in an emergency. They were also built with a tower or “sail” on top, a structure that would be visible on the surface from a distance. All of the subs had a built-in acoustic communication system like a primitive, scratchy sounding phone. The “telephone” wasn’t completely reliable, due to thermoclines and acoustic scattering layers, but they generally worked. Furthermore, they were all certified by the American Bureau of Shipping in order to operate in US waters and to obtain insurance.
The Trouble with Titan
The Titan submersible was an experimental system, as acknowledged by the owners. To my knowledge, Titan lacked many of the safety features present in research submersibles, such as:
Spherical pressure chamber. The tubular structure is weaker than a sphere, despite (or maybe because of) it being a composite of carbon fiber and titanium. This could have been tested, but the owners (OceanGate) chose not to have it inspected by either the ABS or another inspection authority.
Droppable weights. To drop their weights, they had to roll the Titan sideways by having the passengers lean to one side, which might work without battery power, but seems pretty unreliable.
Openable Hatch. Even if the Titan managed to surface, the crew could not escape without assistance.
Top Sail. Titan had no visible sail, so it would have been extremely hard to see it on the surface.
Tracking system? Reports are conflicting as to whether or not the Titan had a tracking system, which would have helped determine exactly where they were once they lost communication. James Cameron said in an interview that it had one, and that it was destroyed at the same time the sub lost communication, which he took as indicating an implosion had occurred. That this occurred after one hour and 45 minutes also suggests that they were not on bottom when it happened.
Joystick. Many commentators have criticized the fact that it was operated using a game controller, but those are a well-developed technology, easy to replace, and are often used to control underwater robots.
How Can We Continue to Explore the Deep Sea?
What happened to the Titan is a terrible tragedy for all involved. Many in the scientific diving community were aware of the shortfalls of the Titan design and avoided working in it. In that respect it was never a matter of whether it would fail, but when.
It is not my goal, however, to point fingers or lay blame - plenty of others are doing that. Rather, to ask the question: Why should we continue to put humans into such an unforgiving and dangerous situation – enclosed in a steel can thousands of meters underwater? In fact, much of the research previously conducted using HOVs can now be conducted by ROVs or autonomous underwater vehicles (AUVs). So, is the potential cost in human lives worth the risk?
Having used HOVs, ROVs, and AUVs, I can tell you that there is a great difference between observing the seafloor remotely and in person. Looking at a flat pixelated video monitor gives a limited impression of the underwater scene being observed, but it is difficult to determine size, distance, or relative location of objects, and impossible to keep your bearings as the ROV moves around. Being there in-person is a completely different experience – with two eyes, you can determine size and distance of objects, and as the sub moves around, you can determine your own spatial orientation relative to the external world.
In short, if it is possible, affordable, and safe to visit the underwater world in person, the experience provides much more than just sensual feedback. It allows us to experience the reality of another world. One that we can’t appreciate or even imagine in our daily experience, and that we cannot perceive or understand using remote viewing. It opens our minds.
In spite of the Titan tragedy, humans need to continue exploring. We just need to do it in as safe a manner as possible. And, like space travel, participants should understand the risks involved. It’s one thing to risk your life for science or exploration. It’s another altogether to do it for the sake of tourism. IMHO, the expense, and rarity, of such experiences bestows a responsibility on all those who undertake them to ensure that they produce the greatest possible gain in knowledge, science, and human experience that is possible. And that they share it with the rest of us.
Having said that, it is my intention to start sharing my scientific experiences more widely, including those in the underwater world. Starting next month, I will begin to publish what I consider to be “chapters” that could eventually amount to a book of sorts. Please stay tuned to Ecologist at Large for future explorations.
Fascinating! Most reasonable thing I've read yet re: the Titan tragedy. Thank you for sharing your experience(s).