231–240 of 302 posts
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Their reasoning is fundamentally flawed. > The vast majority of marine (and aviation) accidents are a result of operator error, not mechanical failure. As a result, simply focusing on classing the vessel does not address the operational risks. Aka "classing doesn't mitigate all problems, so we're not going to do it at all"
I've heard the same argument against unit testing and strong typing.
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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?
> Although, couldn't they just leave it at the bottom for a month and see if it implodes? No, cyclic stresses are a different animal altogether. But considering it's just a matter of attaching ballast to sink it, dropping ballast to raise it, there's nothing preventing cyclic testing vs. static @ max depth over the same duration. It seems obvious to me that you'd want to burn through a few test hulls characterizing t…
Your data will be all over the place from surplus to surplus sale.
[1] https://www.insider.com/oceangate-ceo-said-titan-made-old-ma...
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The design flaw was that they used a construction material strong in tension, but weak in compression. For a task that is almost entirely compression. On a vehicle that has no need for weight savings. Also in a couple photos looks like they have drilled and screwed a monitor mount directly into the pressure vessel, creating future failure points, rather than gluing a piece of plywood to the hull and screwing into tha…
>On a vehicle that has no need for weight savings Most deep sea submersibles only seat a couple people, which wouldn't work for the 'titanic tourism carnival ride' business model. I would guess the weight savings were intended to enable a sub with more capacity that could still be winched on and off the support ship without more complex/expensive heavy lifting equipment.
A modern DSV for Challenger Deep (2x the pressure) used Isofloat to save weight and improve buoyancy.
> They [inspections] do not ensure that operators adhere to proper operating procedures and decision-making processes – two areas that are much more important for mitigating risks at sea. As a former tall ship captain: No Shit. Ships stopped sinking when we started requiring inspections and design rules around stability and watertight compartments. We largely eliminated a common failure mode, designer error, through…
As another tall ship, and for that matter in-shore commercial captain I found this quite telling. > While classing agencies are willing to pursue the certification of new and innovative designs and ideas, they often have a multi-year approval cycle due to a lack of pre-existing standards, especially, for example, in the case of many of OceanGate’s innovations, such as carbon fiber pressure vessels and a real-time (RT…
I'll also recall the sinking of the Herald Of Free Enterprise - a roll on/roll off ferry that departed Zeebrugge and "rolled over" in shallow water due to the bow door being left open - ie stupidity and a lack of monitoring. That wasn't a tall ship but the same general rules apply.
Those are three samples from 400 years of maritime history. The Vasa was a daft design from the outset (meta vs cog), Mary Rose a daft refit after 30 years of service (it was OK for 30 years and then wasn't) and Herald was basically abused by her crew and lacked monitoring.
Now submarines are pretty new. We do have a fairly long history of making pressure hulls from steel and some other materials but they all build upon earlier designs and they have all been tested with a lot of loss of life for failed designs - the history of submarines is pretty sad.
I gather that all very deep sea hulls are basically spherical. The Titan's pressure hull was made of carbon fibre which I gather no one else has used like that. As well as a novel material its shape was elongated to allow more passengers - that's two changes. Finally we also have a viewing port at the front that was actually tested but never rated for 4000m.
No one really knows what happens to carbon fibre pressure hulls when they go from one atmosphere to 180 and back again, repeatedly, then they are picked up out of the water - more stress and strain. Also, no one really knows what happens at the interface of a "window" to carbon fibre at 180 atmospheres.
There are lots more questions to be answered but frankly I see a company trying to run a submarine with DevOps attitude (move fast and break things) rather than proper maritime grade engineering. At 180 times atmospheric pressure, you die within seconds. No ifs and no buts.
I absolutely stand with you guys in insisting on standards for this sort of thing. It isn't the same as running up Everest or going into space. Deep sea is way, way more dangerous.
> They [inspections] do not ensure that operators adhere to proper operating procedures and decision-making processes – two areas that are much more important for mitigating risks at sea. As a former tall ship captain: No Shit. Ships stopped sinking when we started requiring inspections and design rules around stability and watertight compartments. We largely eliminated a common failure mode, designer error, through…
As another tall ship, and for that matter in-shore commercial captain I found this quite telling. > While classing agencies are willing to pursue the certification of new and innovative designs and ideas, they often have a multi-year approval cycle due to a lack of pre-existing standards, especially, for example, in the case of many of OceanGate’s innovations, such as carbon fiber pressure vessels and a real-time (RT…
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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?
You can argue, but it won't be with me on the other side. I don't have a dog in that fight.
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As another tall ship, and for that matter in-shore commercial captain I found this quite telling. > While classing agencies are willing to pursue the certification of new and innovative designs and ideas, they often have a multi-year approval cycle due to a lack of pre-existing standards, especially, for example, in the case of many of OceanGate’s innovations, such as carbon fiber pressure vessels and a real-time (RT…
You guys are tall ship masters. Your vessels are generally well understood these days but let's not forget some comparable disasters: Vasa and Mary Rose. Yes both are from a long time ago but both were based on top of a lot of good solid engineering but both pushed the envelope somewhat and perished. Vasa design basically forgot to sort out the various CoGs for a ship - it was top heavy. Mary Rose loss is a bit more…
Discount, too-old-for-aircraft-use carbon fiber, apparently:
https://www.insider.com/oceangate-ceo-said-titan-made-old-ma...
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That's exactly it. If OceanGate had build and dropped a few dozen of these hulls empty, as many times as needed to reach failure, whatever design flaw caused the implosion almost certainly would have been noticed. It's the hubris of diving in what amounts to a prototype that's at issue here, not any fundamental technical mistake.
The design flaw was that they used a construction material strong in tension, but weak in compression. For a task that is almost entirely compression. On a vehicle that has no need for weight savings. Also in a couple photos looks like they have drilled and screwed a monitor mount directly into the pressure vessel, creating future failure points, rather than gluing a piece of plywood to the hull and screwing into tha…
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Also: the reason most accidents are due to operator error and not mechanical failure is because the requirements exist in the first place. "Why do we have laws against slavery? It's not like anyone actually owns slaves. Seems pretty superfluous, so let's just get rid of it!"
Wasn't that the argument the SCOTUS used to undo the Voting Rights Act?
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The linked article is very clearly an attempt to persuade its reader that the lack of classing (IE verification of safety by an external auditor) is less of an issue than they might otherwise think. Your advice to a reader of this article is rational here, but I think it's worth also pointing out that the article is meant to persuade said reader to not think that way
Perhaps this might be a cultural issue (I am not a US-American citizen), but to me your quote > "We're so innovative we don't have time for safety regulations" reads like "to offer an innovative service which would otherwise not possible, we exchanged known risks (what safety regulations are for to capture and mitigate) for much more unknown risks". As I wrote: "risks that are likely very hard to actually measure are…