James Cameron about to dive 7 miles

Not a porthole in the sphere, but the plexiglass window in the tunnel shelter.

After all the hype, I thought Cameron would be have had a better vehicle. Except for the better lights and cameras, it is just the same "elevator" type system as Trieste before we rebuilt her. Really not much better than Beebe's Bathysphere. Trieste II (Trieste rebuilt as DSV-1, now at the museum in Keyport WA) was a much more useful vehicle, and even given the technology of the day, realisticly more advanced.

 

The pressure involved are so great that it is best to keep it simple and robust. Nothing fancy here. Notice he had same problem they had on Trieste they are going to have rebuild sections of subs because of cracks.

In reality this is a perfect mission for a robotic vessel. It take so long to get up and down that it leaves very little time for a real mission.

 

What is the maximum time at the bottom?

 

According to the website, he can scrub air for 60hrs

According to the news report, took about 90 minutes to reach bottom at around 35k ft and 70 minutes to surface. Also add time for search and secure before he can open the hatch.

 

> According to the website, he can scrub air for 60hrs

Two days plus emergency time is a long possible mission!

 

Agreed, but to do it solo?
You have to be a pretty determinaly driven individual.

I like people like that.

 

Everyone understands that you don't eat solid food for 72 before diving...right? "Piddle packs" can only do so much. Anyway, normal DS/SOC (MAN-010/P-9290) convention is to try and have a minimum of 72 occupant hours reserve available at the end of the dive. That about how long it would take to get a vehicle to the scene to conduct a rescue in the event of an entanglement; c.f. the Pisces III and SEa Cliff (DSV-4) casualities.

 

I did not know there was such a safety margin, but it makes sense. So he can scrub air for 60 hours, but it's ideal to have 72 occupant hours reserve... how do those two numbers reconcile?

 

They don't. It is one thing for a person to risk his own life in a venture running on the margins, it is another to tell someone it is "safe" to dive a vehicle. I never sign my name to the paperwork unless I feel that everything reasonable and prudent, with OQE, has been done to ensure that undue risks are not being taken. That is what Deep Submergence Scope of Certification is all about. Not having to tell some child that thier parent died because somebody didn't do thier job correctly. Make no mistake, DS/SOC is expensive and one of the reasons that ROV's/AUV's dominate the field now.