Tourists onboard the missing Titan submarine visiting the wreckage of HMS Titanic will be "conserving oxygen," claims a former diver.
The tourist exhibition which sees those wanting to visit the resting place of the cruise liner sees a submarine dive to depths of up to 13,000 feet below sea level.
However, the Titan submarine lost all contact with its ship on Sunday, sparking a global frenzy and rescue effort to find those onboard.