Stockton Rush is dead, and he is the guy most directly responsible.
yesterday I did say in a post :
"I just don't think carbon-fiber is a good material for this application. It's very strong in CERTAIN directions but it can degrade and have weak spots and it CAN shatter too. And it's strength depends on how well it's laid and how well it's baked in an Auto-clave. Making it is not like metal at all -- it requires multiple layers criss-crossed in specific angles to each other etc.
Apparently the cylindrical part of the hull was made from it, apart from the titanium end-cap. The join I think would be an issue and you really don't need lightweight in this application, you need 100% reliable strength and resistance to fatigue, cracking, corrosion, tears in your material etc."
and it seems James Cameron from his post today (assuming it IS him and i'm sure it is) effectively agrees that carbon-fiber is not a material to use for an application like this. Whole thing should have been steel alloy or titanium alloy. Or it may have been the viewing port that failed as it was allegedly not rated to anywhere near this depth of 3800meters.
Anyway, R.I.P. to the dead but it could have been avoided by better design and testing.