PARIS, France — A French submarine operator and daredevil deep-sea explorer dubbed "Mr. Titanic," who died onboard a submersible visiting the wreck of the mythic ship, was hailed on Friday as having helped advance mankind's understanding of the "unknown world."
Paul-Henri Nargeolet, 77, was one of five people in the tourist submersible which was revealed on Thursday to have suffered a "catastrophic implosion."
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The news brought an end to an international search and rescue mission in the North Atlantic that had captured the world's attention.
Nargeolet had previously gone on more than 30 dives to explore the Titanic, even bringing up some of the first objects recovered from the wreck after its discovery in 1985.
The tight-knit community of French deep-sea explorers were quick to express their grief.
Bernard Cauvin, head of the Cite de la Mer maritime museum in Cherbourg, western France, said it was "a sad, sad, sad end for a giant of the deep."
Nargeolet "helped humanity understand this unknown world" of the deep sea and had "captivated everyone with his restraint, delicacy and humility," Cauvin added.
Before the sub's fate was revealed on Thursday, Nargeolet's daughter Sidonie told French broadcaster BFMTV that she hoped for a positive outcome.
"But in any case, he is happy where he is. And that is reassuring," she said.
Cauvin said he shared this feeling: "He is happy where he is."
Nargeolet had been expected to attend the opening of a new exhibition in Paris devoted to the Titanic on July 6.
"We salute the passion and courage of this extraordinary explorer and thank him for the dreams and emotions he has given us," the exhibition's organizer Pascal Bernardin said in a statement.
Born in 1946, Nargeolet spent more than two decades in the French navy before joining the French Research Institute for Exploitation of the Sea (IFREMER) in 1986.
The following year, he led the first expedition to collect objects from the wreck.
In 1989, he took over managing the deep-sea sub expeditions of Genavir, the operator of France's oceanographic fleet.
'Insatiable explorer'
"His dives will remain etched in the memory of French oceanography," Genavir's director Eric Derrien said in a statement, lamenting "the disappearance of this insatiable explorer of the ocean."
Xavier Placaud, a manager at Genavir, said he had been on six dives to the Titanic wreck with Nargeolet.
Recounting how together they had explored previously inaccessible parts of the wreck, Placaud said: "These are strong moments that we shared."
Nargeolet lived in the United States working as the director of underwater research for RMS Titanic, which owns the rights to the wreck.
He published the book "In the Depths of the Titanic" last year, the 110th anniversary of the ship's sinking.
The head of the publisher HarperCollins France Emmanuelle Bucco-Cances said she was "deeply saddened" to learn of Nargeolet's death.
"We will remember a passionate, warm and deeply kind man who was an incredible storyteller," she said.
Nargeolet has previously spoken openly about the risks of his exploits in the most inaccessible waters of the world's oceans, often thousands of meters (feet) below sea level.
"When you're in very deep water, you're dead before you realize that something is happening, so it's just not a problem," he told the Irish Examiner newspaper in 2019.
IFREMER said its Atalante ship, which had been sent to the wreck in the hopes of deploying its unmanned deep-sea robot as part of a rescue mission, would start the journey back to France.
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