OceanGate CEO Stockton Rush says the company had been evaluating the potential of using a carbon fiber composite hull since 2010, primarily because it permits creation of a pressure vessel that is naturally buoyant and, therefore, would enable OceanGate to forgo the use — and the significant expense — of syntactic foam on its exterior. So, for Cyclops 2 OceanGate decided to avoid the metallic hull altogether and began a search for a manufacturer that could help it develop a composite hull.
Once again the motive for the choice of carbon fibre seems to have been its relative cheapness.
Consider this thing displaces about 5 m^3 of water, you’d want it to be buoyant after dropping the ballast, so the entire vehicle needs to weigh in at under 5000 kg. You’ve got 400kg of humans, and probably another 600kg of batteries and other equipment.
That means you need your pressure vessel to be under 4000kg. To fashion a 151cm OD cylinder, that was 252cm long, with spherical end caps out of titanium that was 10cm thick you’d need (if my math is correct) a weight of 7,853 kg. That would sink to the bottom of the ocean floor, which is decidedly unattractive.
To be fair, I’m sure each trip out there was very expensive to run. They would have costs for the boat, the fuel, the maintenance, and a full crew with specialist skills.
This diagram shows that the white bits are a glass fiber shell
https://www.compositesworld.com/articles/composite-submersibles-under-pressure-in-deep-deep-waters
It’s not part of the pressurized system so there’s really nothing to rip it to pieces. Definitely no sign of the carbon fiber parts.
Once again the motive for the choice of carbon fibre seems to have been its relative cheapness.
Probably weight too.
Consider this thing displaces about 5 m^3 of water, you’d want it to be buoyant after dropping the ballast, so the entire vehicle needs to weigh in at under 5000 kg. You’ve got 400kg of humans, and probably another 600kg of batteries and other equipment.
That means you need your pressure vessel to be under 4000kg. To fashion a 151cm OD cylinder, that was 252cm long, with spherical end caps out of titanium that was 10cm thick you’d need (if my math is correct) a weight of 7,853 kg. That would sink to the bottom of the ocean floor, which is decidedly unattractive.
When carbon fiber is the cheap option you know things are getting crazy.
And he still charged $250k…
To be fair, I’m sure each trip out there was very expensive to run. They would have costs for the boat, the fuel, the maintenance, and a full crew with specialist skills.
I’m betting the carbon fiber part of the hull was completely pulverized. Nothing left but fragments.