大象传媒

As the search operation to find the missing submersible in the Atlantic intensifies, Titanic expert Larry Daley says the situation is ''heartwrenching''.

Mr Daley has been friends with the highly experienced French mariner Paul-Henri Nargeolet, one of those aboard the missing vessel, since their first expedition in 1998.

"It's really hard to know he's in this situation, but he would be the right man to be in a submersible with if you get in a pinch'', says Mr Daley.

He adds that imagines Paul-Henri Nargeolet would "ask everyone to stay calm and offer advice and his experience."

A French vessel which is able to reach great depths and cut cables, in which the mini-sub may be trapped, is joining others in the search. Estimates suggest the five men on board the Titan sub have less than ten hours of oxygen left.

(Undated photo shows tourist submersible belonging to OceanGate as it begins its descent at sea. Photo by Ocean Gate / Handout/Anadolu Agency via Getty images)