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Why isn't Titan classed? (2019)

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Re: Why isn't Titan classed? (2019)

#201

Post by meghan_rain »

rossjudson wrote: post #120
fredgrott wrote: post #95

One should note that carbon composites are not for external pressure situations since they delaminate...in shorts words they were playing a dice rolling game and lost on damn stupidity. The whole reason they were not classed is that carbon composites would not pass any class certifications due to the limits indicated above.

I'm still trying to understand why they wanted to use carbon composites. Cost to manufacture? Low mass? I read somewhere that the carbon pressure vessel was about five inches thick. I'm not sure how thick a comparable titanium vessel would be, or how much that would cost.

lmao of course it was due to costs. greed killed those people.

Re: Why isn't Titan classed? (2019)

#202

Post by stickfigure »

wkat4242 wrote: post #133
cbzoiav wrote: post #101

Earlier quoted context omitted.

The shuttle did something nobody had done before and was viewed as a genuine step forward in human capability. It was also over 50 years ago and had to rely on technology of the time - uncrewed tests were much harder to perform. This wasn't a particularly ground breaking vehicle in terms of capability and was taking paying tourists...

It also wasn't built with parts from camper world and cheap Xbox controller knockoffs. NASA actually had a strong focus on safety. They just went about it the wrong way, calculating safety ratings backwards. Considering the pressure vessel of this sub was only meant to handle 1300m as per another article, the way it survived 50 dives at 4000m is pretty amazing though.

> this sub was only meant to handle 1300m

There seems to be a lot of confusion around this, let me try to clear it up.

The 1300m limit of the glass number comes from an interview with the "whistleblower" in 2018. That would mean it refers to the Cyclops 1 vehicle they had then. A couple years later they built the Cyclops 2, which has the 5" thick hull, titanium bells, and first dove in 2021. That's the ill-fated Titan.

If you pay close attention to the videos floating around you'll notice two visibly distinct subs - one with a large transparent dome in front (v1) and one with the titanium bell and tiny porthole (v2).

EDIT: This video (taken from a commenter on this page) includes film of the previous sub, playing next to the guy talking:

https://www.youtube.com/watch?v=0mSq6ibKKXQ

Re: Why isn't Titan classed? (2019)

#203

Post by jtriangle »

TeMPOraL wrote: post #195
sacnoradhq wrote: post #175

Earlier quoted context omitted.

Emperor's new clothes syndrome of the naïve and/or arrogant.

As much as I love the show, I'd call it Star Trek's approach to OSHA. I mean, Starfleet officers are so well-trained and perfect that they don't need safeguards such as guardrails on elevators moving engineers up and down a three story high room that ends up shaking at least twice per episode. And let's not even talk about seatbelts.

Well, idk, every time the ship gets hit some console on the bridge shorts out and the arcflash blows some noname ensign across the room. So, star trek probably isn't the example I'd pull from.

Re: Why isn't Titan classed? (2019)

#204

Post by icegreentea2 »

noduerme wrote: post #139
aaronscott wrote: post #100

> Another simple risk mitigation step we take, that we believe to be unique to OceanGate is that we draw a small vacuum on the inside of the sub at the start of each dive. This step verifies the integrity of the low-pressure O-ring seal and eliminates the risk of leaks I wonder what that low-pressure o-ring is sealing. I assume the vacuum would only simulate a one atmosphere differential, so that o-ring must not be s…

One thing I'm curious about, as someone who knows nothing about the engineering of these things... why wouldn't anyone building something like this choose to over-pressure the sub once people were inside it and it began descending? Wouldn't 2 atmospheres inside represent a 50% reduction in the pressure differential on the hull at depth?

Separate from the comments about pressure differential - even 2 atmospheres is probably enough to risk decompression sickness if they just popped the hatch at the end of the dive. So you'd need some way to reduce the pressure gradually. That either needs a way to vent gas out (which means adding a hole in the hull, which you'd really rather avoid having to deal with), or having a compressor inside the hull, or do the entire hatch popping in another pressure vessel. All of those options seem to odds with the 'go cheap and fast' approach.

Re: Why isn't Titan classed? (2019)

#205

Post by ikiris »

rossjudson wrote: post #120
fredgrott wrote: post #95

One should note that carbon composites are not for external pressure situations since they delaminate...in shorts words they were playing a dice rolling game and lost on damn stupidity. The whole reason they were not classed is that carbon composites would not pass any class certifications due to the limits indicated above.

I'm still trying to understand why they wanted to use carbon composites. Cost to manufacture? Low mass? I read somewhere that the carbon pressure vessel was about five inches thick. I'm not sure how thick a comparable titanium vessel would be, or how much that would cost.

For the same reason we are the only nation that builds water-cooled, graphite-moderated reactors with a positive void coefficient. (beat) It's ''cheaper''. — Valery Legasov

Re: Why isn't Titan classed? (2019)

#206

Post by Gwypaas »

pengaru wrote: post #179
cactusplant7374 wrote: post #153

Earlier quoted context omitted.

Each time they go down they have to jettison some waste to return to the surface?

I'm no sub nerd but it seems obvious that unless you can otherwise alter your buoyancy somehow, your only option is to drop weights. I think submarines use ballast tanks they flood with sea water and empty with pumps to vary their buoyancy. Titan had none of that complexity AIUI, and multiple articles I read mentioned dropping "ascent weights".

You can use compressed air. The COPV Spacex uses for tank pressurization are rated higher than the Titanic depth. And as depth increases the differential decreases.

So you really only care about their structural integrity at the surface.

Re: Why isn't Titan classed? (2019)

#207

Post by lamontcg »

foota wrote: post #82
cactusplant7374 wrote: post #72

Earlier quoted context omitted.

It had already been down quite a few times. Do you mean 100's of drops? Although, couldn't they just leave it at the bottom for a month and see if it implodes?

I believe the stresses of the hull going through changing pressures is relevant.

Definitely does for compressed gas cylinders.

Re: Why isn't Titan classed? (2019)

#208

Post by jsjohnst »

jtriangle wrote: post #203
TeMPOraL wrote: post #195

Earlier quoted context omitted.

As much as I love the show, I'd call it Star Trek's approach to OSHA. I mean, Starfleet officers are so well-trained and perfect that they don't need safeguards such as guardrails on elevators moving engineers up and down a three story high room that ends up shaking at least twice per episode. And let's not even talk about seatbelts.

Well, idk, every time the ship gets hit some console on the bridge shorts out and the arcflash blows some noname ensign across the room. So, star trek probably isn't the example I'd pull from.

GP was using Star Trek as a bad example, similar to you.

Re: Why isn't Titan classed? (2019)

#209

Post by tspike »

AlbertCory wrote: post #156
advael wrote: post #113

Earlier quoted context omitted.

The only "unmet needs" such an endeavor need care about is convincing a deep-pocketed investor

Exactly. One could make the same claim about space tourism, but that one has some rational justification at least. I don't see a great benefit in having cheaper deep-water subs.

What’s the rational justification for space tourism?

Re: Why isn't Titan classed? (2019)

#210

Post by c-hendricks »

qayxc wrote: post #161
AlbertCory wrote: post #108

Earlier quoted context omitted.

> We're so innovative what I'm wondering is: what's the incentive to be "innovative" in the first place? Unless "innovation" is an end in itself. Is there some great unmet need to send people to extreme depths, especially when unmanned probes can do most necessar work nowadays?

> Is there some great unmet need to send people to extreme depths, especially when unmanned probes can do most necessar work nowadays? Two reasons: 1) they had plenty of paying customers, so there was a demand 2) the CEO wanted to be remembered as an innovator, views this as being an explorer, and wanted to inspire people (he said so in interviews)

> “I’d like to be remembered as an innovator,” Rush said in the 2-year-old YouTube interview. “I think it was Gen. MacArthur said, ‘You’re remembered for the rules you break.’ And, you know, I’ve broken some rules to make this. I think I’ve broken them with logic and good engineering behind me, the carbon fiber and titanium — there’s a rule you don’t do that. Well, I did.”

And see what happens?

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