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Submarine missing near Titanic used a $30 Logitech gamepad for steering

arstechnica.com

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Re: Submarine missing near Titanic used a $30 Logitech gamepad for steering

#171

Post by tguvot »

teraflop wrote: post #114
tguvot wrote: post #82

Earlier quoted context omitted.

what about fiber ? <4kg per km. throw at end powered buoy. maybe inflatable to hold more of it. currents still will be mess, but with lower than copper weight you could have a few km slack

I think your assumptions are unrealistic. A fiber optic cable weighing 4kg per km with no other reinforcement or protection would be extremely fragile. According to my back-of-the-envelope math, using the density and tensile strength of typical glass, it would have a breaking load capacity of around 10 newtons (roughly 2 pounds of force). Even a steel cable with the same weight would only be about 20 times stronger.

4kg/km it's not for clean glass fiber. it's fiber drop cable, in whatever plastic sleeving + a couple of steel strands for some added rigidity/structure. there are also versions with kevlar braiding to protect core and improve resilience.

Re: Submarine missing near Titanic used a $30 Logitech gamepad for steering

#172

Post by lisasays »

JDW1023 wrote: post #17

> According to the BBC, the entire sub is bolted shut from the outside, so even if the vessel surfaces, the occupants cannot escape without outside assistance and could suffocate within the capsule. Why is the submarine bolted shut from the outside?

Assuming, quite reasonably, that there has to some kind of rationale for this -- I would guess it's because there's some significant structural complexity (and hence risk) involved in having it be open-able both ways.

Re: Submarine missing near Titanic used a $30 Logitech gamepad for steering

#173

Post by analog31 »

Karupan wrote: post #165

According to the NYTimes, OceanGate refused to undergo any sort of external audit/certification process [0]. I would imagine using an off the shelf, cheap controller would have been one of the first things to be flagged. Makes you wonder how many other critical components did they skimp on [0] https://www.nytimes.com/live/2023/06/20/us/titanic-missing-s...

This is what actually amazes me. The reliability of something like an airplane, bus, or train, is held to extremely high engineering standards. There are even safety rules for bicycles. But you're allowed to take people for rides in a submarines with barely any oversight.

Re: Submarine missing near Titanic used a $30 Logitech gamepad for steering

#174

Post by gcanyon »

tzs wrote: post #161
starkparker wrote: post #34

Earlier quoted context omitted.

Naval submarine hatches rely on the pressure to keep the hatch shut. The water pressure outside is greater than the air pressure inside. The hatch locks around a sealing o-ring. Escape trunks are sealed off from the rest of the ship and work like an airlock. Deepsea Challenger's outward-opening hatch/egress trunk worked the same way; indeed, its view window was on the hatch.

> Naval submarine hatches rely on the pressure to keep the hatch shut I don't remember which company it was, but there was an aircraft company that made the mistake of relying on screws instead of pressure to keep the cockpit windows in place. The windows were installed from the outside with outside screws to hold them in place. During maintenance one of the windows got replaced and the worker accidentally used the w…

I think this is the story you're talking about. The replacement windscreen bolts were too narrow: https://admiralcloudberg.medium.com/the-near-crash-of-britis...

Re: Submarine missing near Titanic used a $30 Logitech gamepad for steering

#175

Post by gcanyon »

rhyst wrote: post #146
orangepurple wrote: post #93

Earlier quoted context omitted.

Do the math exercise with him for how much volume 2 miles of string takes up

Using 9mm diameter semi static climbing rope as an example. For volume: Volume of 4km of rope is 0.009^2 3.14 4000 = 1.02m^2 which seems like an amount that would fit on a large spool on a ship. For weight: rope itself weighs about 60g per meter so 0.06*4000=230kg of rope. It has a breaking strength of 22kN, which is roughly 2000kg static load. Given everything is probably roughly neutrally buoyant seems like enough.…

I haven't checked your math, but your volume should have a ^3 on it, not a ^2

Re: Submarine missing near Titanic used a $30 Logitech gamepad for steering

#176

Post by jmount »

CryptoBanker wrote: post #139
rwmj wrote: post #46

There's a BBC documentary from last year which I just watched: https://www.bbc.co.uk/programmes/p0fpz9zw and honestly a lot of it seems quite amateur hour. One of the steering motors was fitted backwards. When they discovered this, at the bottom of the ocean and a few hundred feet from Titanic, the solution they used was to hold the gamepad at right angles to compensate. That time they proceeded with the tour and mad…

The founder/CEO has said that he hasn't been on a single trip where everything went to plan...

Wow, everything working should be the goal- not a mere nice to have.

Re: Submarine missing near Titanic used a $30 Logitech gamepad for steering

#177

Post by komadori »

tzs wrote: post #161
starkparker wrote: post #34

Earlier quoted context omitted.

Naval submarine hatches rely on the pressure to keep the hatch shut. The water pressure outside is greater than the air pressure inside. The hatch locks around a sealing o-ring. Escape trunks are sealed off from the rest of the ship and work like an airlock. Deepsea Challenger's outward-opening hatch/egress trunk worked the same way; indeed, its view window was on the hatch.

> Naval submarine hatches rely on the pressure to keep the hatch shut I don't remember which company it was, but there was an aircraft company that made the mistake of relying on screws instead of pressure to keep the cockpit windows in place. The windows were installed from the outside with outside screws to hold them in place. During maintenance one of the windows got replaced and the worker accidentally used the w…

It was BA flight 5390. Admiral Cloudberg has a good write-up: https://admiralcloudberg.medium.com/the-near-crash-of-britis...

Re: Submarine missing near Titanic used a $30 Logitech gamepad for steering

#179

Post by cpleppert »

srmarm wrote: post #3

The US Navy uses an Xbox 360 controller in active service [0] Mass market has a lot of R&D to leverage so it makes sense. Nothing to say this is the cause of the fault and probably going to be more reliable than something hand rolled. [0] https://www.theverge.com/2017/9/19/16333376/us-navy-military...

The Xbox controllers are used to control the periscope which is not a safety critical device. Regardless, the navy uses wired controllers and did extensive testing and verification. This outfit didn't do anything like that; in one video with a journalist the bluetooth controller was a 'feature' because they could pass it around the sub.

Re: Submarine missing near Titanic used a $30 Logitech gamepad for steering

#180

Post by bitshiftfaced »

thesausageking wrote: post #98
aezart wrote: post #7

The fact that it's wireless is the scariest part to me. What if it runs out of battery? What if it desyncs?

They have multiple of them on board and can swap in a new one if there's an issue. The focus on the controller is misplaced to me. Game controllers are well made and better suited for the job than custom hardware. It's just the association with videogames that makes it seem odd. If they used $30 logitech keyboard as well, would anyone question that?

Pros of having a wireless controller: freedom of movement (in this case in a very cramped environment) and not having as much of a tangled cord situation.

Cons: desynchronization issues, transmitter goes bad, receiver goes bad, interference, batteries run up, someone forgets to pack batteries, someone forgets to check if the backup batteries are still good.

WHAT were they thinking??

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