[learn_more]

I too am perplexed. Perhaps the compressive strength is all derived from the epoxy not from the carbon fiber.

[UniverseHacker]

Yes, this doesn't make sense to me either. I suppose it could help prevent bucking and crack propagation, because as the walls of the sub started to bend, one side would have to suddenly be in tension? Still, I wonder if a pure plastic/epoxy hull would have actually been stronger than composite in this situation.

[marcosdumay]

From the design they published of it, I do really think they intended to have the carbon fiber tensioned between a pair of titanium rings.

I understand epoxy doesn't deal well with that, but with the right plastic, I believe it could work very well.