The read between the lines from all the experts I've heard talking about the sub is that it's most likely something catastrophic happened at the start of the mission when they lost comms.
Unlike military/government/non-experimental subs, which are scanned/tested for micro-cracks, stress fractures and so on, the Titan wasn't, and had done a relatively large number of dives for an experimental sub. So on the balance of probabilities, the most likely scenario is that it imploded early on in the mission.
The read between the lines from all the experts I've heard talking about the sub is that it's most likely something catastrophic happened at the start of the mission when they lost comms.
Unlike military/government/non-experimental subs, which are scanned/tested for micro-cracks, stress fractures and so on, the Titan wasn't, and had done a relatively large number of dives for an experimental sub. So on the balance of probabilities, the most likely scenario is that it imploded early on in the mission.