that type of pressure bottle. but for something that s seeing external pressure all of the advantages of composite materials go away and all the disadvantages come into play. so if you re using a uniform material like steel or titanium or ceramic or acrylic, you can do computer modeling with a high degree of accuracy and confidence. the second you start doing carbon composite or any kind of composite materials you re introducing two materials that are in contact with each other. the filament itself and then the epoxy matrix that it sits within. and at that point you have degradation failure. so we always understood that this was the wrong material for submersible hulls because with each pressure cycle you can have progressive damage. so it s quite insidious. because you may have a number of successful dives, which is what happened here, and then have it fail later.
start doing carbon composite, or any kind of composite material. they re introducing to materials that are in contact with each other. the filament itself, and then the approximate tricks that it sits within. at that point, you have degradation failure. so, we always understood that this was the wrong material for submersibles. because with each pressure cycle, you can have progressive damage. so, it s quite insidious. you may have a number of successful dives, which is what happened here, and then have it fail later. if i were diving in a sub that was fully certified, i wouldn t think about it. even in my own sub, which had a steel hull, i knew that if i dove several two or three times, it was probably good to go, you could cycle steel hundreds of times. if not thousands of times. that s not the case with the composite.
not engineers separately raised concerns about the safety of the hull of the titan sub made of composite materials. james cameron who has made over 30 dives to the titanic says that it is known to the engineering community. we have always understood that it is the wrong material for the submersible hulls, because with each pressure cycle, you can have pressure damage. it is insidious, and this is what led to the overconfidence and led to the tragedy. reporter: i interviewed is stockton rush as a reporter in seattle, and i pressed him about the safety of the vessels, and he told me that he viewed submersibles as armored vehicles, kate. before another expedition he said to me, quote, everyone is getting back safe, and we can take risks with equipment buck not people, and many in the
we always understood that this was the raw material for a submersible hull . with each pressure cycle you can have progressive damage. it is quite insidious. you may have a number of successful dives, which is what happened here, and then have it failed later. if our diving in a summer rain fully certified i would not think about it. even in my own steel hull i knew if i dove two or three times it was probably good to go. you can cycle shahzada dawood hundreds of times. that is not the case with composites. i think that load them into a sense of confidence and led to this tragedy. these are known things within the engineering community. director james cameron, will have more of that interview throughout the morning. back to you guys in new york. there are so many questions. clearly everyone involved knew there was some risk. we are learning and questioning how much?
will cohen says he wrote to rush concern oceangate was not following the same safety standards as other vessels. in a 2018 letter first obtained by the you were new york times he warned about the experimental approach that could have serious consequences. cnn has as the reported two former oceangate employees were not engineers severally raise safety concerns years ago about the hull of the tightend. the hull was made of carbon fiber composite, the type of material used in spacecraft. filmmaker james cameron who has made more than 30 dives himself says the danger of using this composite is known within the engineering community. we always understood this was the raw material because with each pressure cycle you can have progressive damage.