Race to the bottom of the ocean

BBC ^ | 22 February 2012 | Written by Rebecca Morelle.

[csvset]

The race is on to reach the deepest place in the ocean: the Mariana Trench, which plunges 11km (7 miles) down.

Fifty years after it was first conquered, four teams are vying to return. It will be an epic journey that will push submersible technology to its limits and put the lives of those piloting the vessels at grave risk.

Each team has a unique approach, but over the course of the next year only one will be crowned the winner in this journey beyond the abyss.

[Gandalf_The_Gray]

What will really blow your mind, the two halves of the round globe the men were in was super glued together.

Where did you read that? It was a steel casting with 6" wall thickness. In any event, cyanoacrylate glue was not widely available 60 years ago. As a class of adhesives, cyanoacrylates are classified as having "weak" resistance to moisture, making their use to fabricate submarine parts questionable at best.

Regards,
GtG

[org.whodat]

History channel, has a show about it same as discovery, after they glued it and tested it they rigged a metal strap around it to keep the two halves in alignment. Maybe be available on computer try a search. I saw it years ago.

[Gandalf_The_Gray]

Thing was filled with sand, when they wanted up they pulled a lever and the sand started running out. And up they came.

Close but no cigar. Have you ever tried to get wet sand to move through a small hole? The ballast was steel shot held in two "silos". The shot was blocked from falling out by electromagnets, when you wanted to "blow tanks" you turned off the juice to the magnet and dropped some shot. Neat safety feature 'cuz if you lost power you automatically dropped all ballast and went positive buoyancy.

BTW the hull was sheet metal and it was filled with aviation gasoline to give the ship a fixed positive buoyancy without the shot in the silos.

Regards,
GtG

[org.whodat]

Call discovery and tell them to correct their film.

[Gandalf_The_Gray]

I was talking about the bathyscaphe for going into the trench...A steerable submersible of some kind.

Exactly what do you think the bathyscaphe was, if not a steerable submersible? It was not connected to a surface ship, carried it's own power for steerable thrusters, and dive time was limited only by battery power and crew endurance. After a crack developed 5 hours into the dive they continued to the bottom, took pictures, and returned safely to the surface.

Regards,
GtG

PS They reported seeing fish at the bottom of the trench!

[Jonty30]

I wasn’t aware that you could steer it, so thanks. That is interesting.

[Gandalf_The_Gray]

Call discovery and tell them to correct their film.

I think I may have found the problem, there were two bathyscaphes named Trieste and Trieste II. The first named submersible was the record breaking one and did indeed have a "two piece" sphere. I don't know how it was held together but super glue sounds a little bit risky. The joint is always loaded in compression and will actually get stronger as you descend so that not a problem. After the record dive I believe it was acquired by the French navy and used in the Mediterranean Sea. It was finally sold to the US Navy. The US Navy also purchased another "Trieste" built in Italy with modifications to make it more seaworthy. The second ship had a Krupp cast steel pressure hull. The Navy used this craft to recover parts of the lost sub "Thresher".

Both of these vessels used steel shot for ballast. It would not be the first time either Discovery or History Ch screwed up something in one of their films.

Regards,
GtG

[golux]

Well, GtG, you may now officially say that you have a friend whose father went down in one of the early bathyscaphes.

Something you won’t read about in the history books is that in those days one shared a bottle of wine on the long way down. And on the way up? Where to pee? You guessed it.