Titan and the burden of rejecting engineering precedent

What engineering lesson should be taken from the Titan submersible disaster?

Investigate why established designers rejected a material or method before assuming that convention reflects a lack of imagination.

Earlier marine engineers may have had sound reasons for rejecting a material or method. An unconventional design therefore needs more justification than confidence that its designer is cleverer than previous generations. Established material choices are a reason to investigate the engineering constraints before departing from them.