This is misleading. Only raw CF is like a rope, once made into a composite with resin it becomes a stiff member with entirely different properties. It's more a

This is misleading. Only raw CF is like a rope, once made into a composite with resin it becomes a stiff member with entirely different properties. It's more analogous to a wood beam - very stiff and resistant to bending but once you get past it's limit it cracks. I suspect the failure mode in a submersible like this isn't so much the carbon fibers themselves but either the carbon > metal interface at the ends or gradual delamination between layers of fibers due to the cyclical pressure loads.