Experts think Titan submersible imploded due to design defects

Many observers agree that the materials and design of the Titan could have made the underwater vessel vulnerable. 

The hull was also made longer so that there would be more room inside for customers and other people.

But it is the materials that concern mechanical and marine engineer Jasper Graham-Jones: "Also, they've made it out of composites and normally it's made out of titanium, a hull. And they've made this out of composites. Yes, composite is extremely tough. Yes, composite is extremely long-lasting. But we do have issues with composites and the fact that composites fail in slightly different ways than other materials."

The thickness of the hull has also been called into question.

Observers say five inches (12.7cm) is very thin, given the pressures it had to withstand at such depths.

Experts also say the vessel, in which five people died when it imploded, had no type of formal approval.