'Debris field' discovered in search for
Titanic sub contains its 'rear cover and
landing frame' which indicates 'catastrophic
implosion', say experts

Might have been better way to go than slowly running out of oxygen.

My thoughts exactly #1. Awfully expensive way to die though.

This article has a grapic showing the rear cover and the landng platform. Sounds as though the 5” thick plastic hull could not withstand the pressure. Maybe a crack and then implosion?

"The family of British billionaire, Hamish Harding, have spoken of their fury that it took OceanGate's mothership, the Polar Prince, eight hours to report the sub missing on Sunday." fury... oh.. THAT should be reason enough to sue someone.. nothing to do with the passengers..

Well, sympathy to all affected, Any loss of life is tragic, I doubt if next week's voyage will be going out as scheduled, though. Like I said, if I'm gonna pay $250,000 to ride in a boat, there'd better be a cute girl serving me free drinks.

Hmmm. 800,000 lbs of force applied to every square foot....when that shell began to fail, it was a buckling failure, which is "nonlinear", meaning OK one second then zap, not OK. Example of buckling failure to get a handle on this. Put the end of a soda straw against something the will keep it from sliding, like carpet, and then with a gloved hand, apply pressure along the length of the straw....it will hold a somewhat surprising amount of force as you increase the pressure....until it buckles and collapses totally. I don't think anyone knew anything about what happened, possibly a creak or a crack.....then almost six thousand pounds applied to every square inch. Perhaps it might be better to use subject matter experts....who are mostly white guys over fifty.

Clarification.....force on the opposite end, oriented along the direction of the straw.

The owner of the company (victim) was being sued by a former employee for disregarding the poor quality of carbon fiber material being received and for failing to address cracking of the composite material with exposure to cold and repeated pressure cycling. Sounds like the owner found out who was right in that case.

It's interesting the pressurized hull was found to be in fragments. It cracked like an egg beneath a bulldozer. The guy who warned in 2018 that this company's designs were insufficient will probably be getting a lot of interviews.

Now to figure out what the knocking sounds were.

Probably fatigue failure, carbon fiber is not steel. Did some reading the last few days on bathyscaphe Trieste. The pressure vessel was made from 5" thick steel to withstand the 2.2 million lb/sf pressure of the Mariana Trench. It only held two people though.

Re #3, calling a wrapped carbon fiber hull "plastic" is pretty inaccurate. The composite would typically be about 70% carbon fibers and 30% polymer resin by volume. So, yes, 30% or less is "plastic", but the strength is primarily from the carbon fibers. And the percent carbon fibers could be higher, depending on the particular process used to create it. Carbon fiber composites can be designed, and properly built to be extremely strong and stiff, and can easily match steel or titanium in certain loading conditions. . But, fiber composites excel at tension loading, and are much less capable in compression loading. The loads on the cylindrical shell due to external water pressure are all compression, not an ideal match of material choice for this loading condition. As good as composites can be, one of the difficulties with any composite structure is making structural transitions from composites to metals which don't reduce the strength of the structure. Proper joint design is complex and difficult. I am very suspicious of the bonded joint between the titanium end rings and the carbon fiber cylinder. But, the window is also a huge structural question mark. The existence of a hole in the sphereical end cap causes very much higher stresses around the hole in the titanium, and the window itself has mind boggling loads on it....almost two million pounds of force on the window alone.

Hate to come across as a ghoul but my sympathy goes to people who are killed or injured doing what needs to be done. People who needlessly risk their lives for some kind of thrill do so at their own risk. When a mountain climber falls to his/her death I am not happy but they chose foolishness. If I were suspended over the crater of an active volcano I could get a really close look at lava. Why should I do that when I have the National Geographic Channel?

The Daily Besst has “chilling” tales of malfunctions and aborted trips due to mechanical and communication problems on their toy submarine. These men paid $250K to die on a vessel “made from a kit” that Walmart would not sell...

Interestingly, the carbon fiber composite ended up behaving like plastic. Cracked like a egg under pressure.