Paul-Henri Nargeolet, a famend French maritime knowledgeable and submersible pilot, grew to become a number one authority on the H.M.S. Titanic by means of 37 profitable journeys to its wreckage. He was killed on his thirty eighth try when the submersible craft in which he was traveling with four others imploded, the U.S. Coast Guard introduced on Thursday. He was 77.

Perhaps nobody was extra intimate than Mr. Nargeolet with the wreck of the White Star liner that settled almost 13,000 toes deep within the North Atlantic Ocean after sinking in 1912, killing greater than 1,500 passengers and crew members. Often referred to as “Mr. Titanic” for his data of the ship’s wreckage and environs, he was the director of underwater analysis for RMS Titanic, the corporate that owns the salvage rights to the storied shipwreck, and the creator of the book “In the Depths of the Titanic,” lately revealed by HarperCollins France.

His dozens of dives to the positioning included expertise on the Titan, the vessel that disappeared on Sunday en path to the wreckage. On one such journey, in 2022, he helped with the invention of an “extraordinarily biodiverse abyssal ecosystem on a previously unknown basalt formation near the Titanic,” according to the company that owned the Titan, OceanGate Expeditions.

James Cameron, the director of the favored film “Titanic” and a good friend of Mr. Nargeolet’s, described him as a “legendary submersible pilot.”

“For him to have died tragically in this way is almost impossible for me to process,” Mr. Cameron, who himself has made 33 dives to the well-known wreck, mentioned in an interview with ABC News on Thursday.

Few knew the wonders, in addition to the dangers, of such a dive greater than Mr. Nargeolet. “If you are 11 meters or 11 kilometers down, if something bad happens, the result is the same,” he mentioned in a 2019 interview with The Irish Examiner. “When you’re in very deep water, you’re dead before you realize that something is wrong, so it’s just not a problem.”

Mr. Nargeolet was born on March 2, 1946, in Chamonix, France, within the French Alps. He moved to Paris after residing in Morocco for 13 years.

He heard the decision of the ocean at an early age as an newbie diver, and in 1964 joined the French Navy. He served as submarine pilot, mine-clearing diver and a deep-sea diver.

After 22 years of service, he went to work for the French maritime analysis institute Ifremer, the place he oversaw its deep-sea exploration crafts throughout early expeditions to the positioning of the Titanic. He made his first journey to the positioning in 1987.

During that 100-minute plunge, the crew of three touring in a submersible referred to as the Nautile chatted incessantly till they lastly caught a glimpse of the liner’s bow within the searchlights. “For the next 10 minutes there wasn’t a sound in the submarine,” he mentioned in an interview final 12 months with HarperCollins France.

His survivors embody his spouse, Anne Sarraz-Bournet; two daughters, Chloe and Sidonie; a son, Jules; a stepson, John Nathaniel Paschall; and a grandson. His spouse Michele Marsh, an Emmy Award-winning newscaster in New York, died in 2017.

As a director for the RMS Titanic firm, which salvaged greater than 5,500 artifacts from the wreckage and in line with the corporate’s web site mounted exhibitions considered by greater than 35 million individuals, Mr. Nargeolet skilled gratitude for his function in preserving what many take into account an emblem of the early twentieth century optimism about technological progress, in addition to scorn from some who take into account it the equal of grave robbing.

“These expeditions have cost $50 million,” he advised The Irish Examiner. “Of course, the company wants some return.”

He emphasised the advantages to science and historical past of preserving the remnants of a large hulk of metal and iron that serves not solely as a teeming habitat for uncommon species — “an oasis in a huge desert,” as he put it in an interview with Le Monde final 12 months — but additionally as one of many nice artifacts of a misplaced age that microorganisms are slowly turning into stalactites of rust.

“One morning, a survivor reproached me for recovering objects, her father having died in the catastrophe,” Mr. Nargeolet mentioned in an interview final 12 months with the French newspaper Le Monde, “and in the afternoon, another congratulated me and asked me to bring back the pearl necklace that her mother had left on her night stand!”