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Titanic tourist submersible goes missing with search under way

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Re: Titanic tourist submersible goes missing with search under way

#271
post #259

Earlier quoted context omitted.

The hatch is bolted shut from the outside. When you make it back to the surface, there is no way to get out without external support. If the mother ship can not find the sub the occupants could be trapped bobbing just below the surface until their air runs out.

Could they just have some drills with diamond-tipped bits stored inside for emergency use? If needed, drill through the whole shell, stick an arm out and unbolt from the outside. Or maybe a jackhammer to just hammer through whatever glass is there for observation purposes.

I don't think there is any glass. Both of the end caps are supposedly titanium and there are cameras.

Re: Titanic tourist submersible goes missing with search under way

#272

Skimming the website, I assume this submersible is using electromagnetically attached drop-weights so that if anything goes wrong and power is lost, the weights drop off and the submersible floats up to the surface again? And 96 hours of life support sounds good, but unless there is another submersible nearby that can dive down, find them AND attach a line, the number of hours of life support will be irrelevant. Of c…

I've read that many military submarines have an "I've sunk" buoy. It detaches from the boat under commanded deployment, after some elapsed time without reset, or when external pressure rises way beyond crush depth. They're positively buoyant. They have radio beacons to report the event when they rise to the surface. edit: No cites, sorry.

https://en.wikipedia.org/wiki/Rescue_buoy_(submarine)

Re: Titanic tourist submersible goes missing with search under way

#273

"Rear Adm Mauger said the rescue teams were "taking this personally" and were doing everything they could to bring those on board "home safe". What does that even mean? Is this opposed to your normal non-personal/strictly professional mode where you would not do everything you could?

There's no need to analyse things so deeply. It's just human expression.

There not being a need doesn't stop me, this too is human expression.

Re: Titanic tourist submersible goes missing with search under way

#274
post #240

Earlier quoted context omitted.

Indeed. Which is why space is easier than the deep ocean, a fact that whoever was on that sub may not have fully appreciated.

If space is easier than the deep ocean, how is it that the Trieste (the submersible that explored the Challenger Deep) was built in a year on a budget of millions by a single shipyard, while it took massive, multi-year, multi-billion dollar, national efforts to go to space?

Difference in difficulty of getting there. The pressure vessel for space could be far simpler than going underwater. But it is way harder to get to the point where you’d need a space pressure vessel in the first place

Re: Titanic tourist submersible goes missing with search under way

#275
post #240

Earlier quoted context omitted.

Indeed. Which is why space is easier than the deep ocean, a fact that whoever was on that sub may not have fully appreciated.

If space is easier than the deep ocean, how is it that the Trieste (the submersible that explored the Challenger Deep) was built in a year on a budget of millions by a single shipyard, while it took massive, multi-year, multi-billion dollar, national efforts to go to space?

National pride was not at stake if Trieste failed.

Re: Titanic tourist submersible goes missing with search under way

#276

Earlier quoted context omitted.

Though choice is still important, why that gamepad? Especially if it was the wireless version. Building the controls with wired arcade buttons and an arcade joystick would be a little pricier but you'd get parts designed to take a beating, plenty of real world usage to demonstrate this and no potentially flaky usb/wireless stack that you have no control over to deal with.

I could take some guesses. It's cramped with a lot of people; wires invite tangles or damage if someone accidentally yanks on it. Especially if you want to operate the vehicle from both sides of the interior. Those controllers have millions of hours of playtesting by people that are sensitive to the slightest twitch. I'd trust them more than most automotive components. I'm more curious to know how they run the contro…

I would not actually trust them more than an automotive component, I think most accelerator pedals use Hall Effect sensors (usually two of them in the good designs) that are much less likely to wear out and cause spurious inputs or failure than the basic potentiometers on a game console, especially a very cheap one. Get an X-box controller at least, and have a couple spares wired in, in case the wireless one fails.

Re: Titanic tourist submersible goes missing with search under way

#277
post #271
post #259

Earlier quoted context omitted.

Could they just have some drills with diamond-tipped bits stored inside for emergency use? If needed, drill through the whole shell, stick an arm out and unbolt from the outside. Or maybe a jackhammer to just hammer through whatever glass is there for observation purposes.

I don't think there is any glass. Both of the end caps are supposedly titanium and there are cameras.

At that point just watch a video, or drive an unmanned submersible.

Re: Titanic tourist submersible goes missing with search under way

#278
post #240

Earlier quoted context omitted.

Indeed. Which is why space is easier than the deep ocean, a fact that whoever was on that sub may not have fully appreciated.

If space is easier than the deep ocean, how is it that the Trieste (the submersible that explored the Challenger Deep) was built in a year on a budget of millions by a single shipyard, while it took massive, multi-year, multi-billion dollar, national efforts to go to space?

There is no launch vehicle to design in the ocean.

Re: Titanic tourist submersible goes missing with search under way

#279
post #240

Earlier quoted context omitted.

Indeed. Which is why space is easier than the deep ocean, a fact that whoever was on that sub may not have fully appreciated.

If space is easier than the deep ocean, how is it that the Trieste (the submersible that explored the Challenger Deep) was built in a year on a budget of millions by a single shipyard, while it took massive, multi-year, multi-billion dollar, national efforts to go to space?

The tyranny of the rocket equation. Or simply put you don't have to carry fuel to carry fuel to carry fuel to get you to the bottom of the ocean. Simply carrying some ballast will do just fine.

The pressure hull isn't the major engineering challenge in getting to space.

Re: Titanic tourist submersible goes missing with search under way

#280
post #30

This appears to be the vessel in question: https://oceangate.com/our-subs/titan-submersible.html Pressure hull made from titanium and carbon fiber, capable of diving to 4000m (13,000 ft). I recall that one reason SpaceX switched from carbon fiber to stainless steel pressure vessels (fuel tanks) was the difficulty of detecting structural flaws. Can any engineers comment on whether that task is easier for a vessel expo…

I've had some work in designing vessels to take external pressure. It's fundamentally a nonlinear problem. A lot of new(and some not so new) engineers don't understand the process of solving it properly For instance, euler buckling is the simple eigenvalue problem of solving a column in compression. But, it misses: initial defect because nothing is truly straight, material nonlinear effects if the part approaches yie…

That’s sounds crazy complicated. In engineering is it like software design where you can get very far just being bad? Like do companies hire just crap engineers who don’t know all this stuff and call it a day? (Kind of like hiring offshore to build mvp for cheapiest crappiest quality possible)
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