Armed Polite Society
Main Forums => The Roundtable => Topic started by: Brad Johnson on August 13, 2020, 02:08:49 PM
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Cable failure at the Arecibo Observatory. Punched a 100 ft wide hole in the dish.
https://www.space.com/arecibo-observatory-damaged-shut-down.html
https://www.youtube.com/watch?v=4V3VCt24tkE
Not something you want happening to one of the most used radio telescopes in the world. I tried to find something referencing how long the wait is for scheduling research time but didn't see anything.
Brad
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I bet it was.... Aliens.
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I bet it was.... Aliens.
(https://www.madaboutmemes.com/uploads/memes/1585317163289.png)
Brad
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The Arecibo Observatory did not kill itself
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Trump, obviously.
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Best way to prep for invasion.
Who had Alians on their 2020 bingo card?
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Trump, obviously.
Maybe Obama. I know his admin chopped funding for green bank telescope while sending National Science Foundation grant money to an observatory in South America.
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I bet it was.... Aliens.
Nope. Bond. James Bond.
https://youtu.be/6HFkF8904Uw
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Friend of mine used to be the public information officer for NRAO. He was not amused with the funding drop to Green Bank.
Of course, since we were in college together he's gone from passively liberal to flaming communist, so he would have been unamused had Trump increased funding to Green Bank.
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Scott Manley's video was great, thanks Brad.
https://www.youtube.com/watch?v=4V3VCt24tkE
Very interesting that the main reflector is spherical so they can "look around," and the corrections to parabolic equivalency are made with secondary mirrors in the observation capsule. Sort of like compound lenses in camera lenses with spherical and chromatic etc aberration corrections. Wow on the math !
I still wonder how come a regular mirror reverses things left and right but not up and down. =D
I had to laugh a bit at 8:16. My only thought was "Big brother is watching you."
Terry, 230RN
Edited to add big grin just because.
Screen capture at the aforesaid 8:16, looking up at the observation capsule:
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"I still wonder how come a regular mirror reverses things left and right but not up and down."
I asked a teacher that in elementary school...
I was told I was disrupting class.
I later figured out that was teacher speak for "Don't make me look stupid in front of a roomful of 9 year olds you little bastard!"
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"I still wonder how come a regular mirror reverses things left and right but not up and down."
I asked a teacher that in elementary school...
I was told I was disrupting class.
I later figured out that was teacher speak for "Don't make me look stupid in front of a roomful of 9 year olds you little bastard!"
Maybe if you laid down on your side it would work. =D
I guess she wasn't the geometry teacher.
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I still wonder how come a regular mirror reverses things left and right but not up and down. =D
How about a non-reversing mirror?
https://youtu.be/x2owiSx0biU
Brad
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Boy, am I glad I went back and added that biggrin emoticon. =D.
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How about a non-reversing mirror?
https://youtu.be/x2owiSx0biU
That voice is hyper annoying.
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.ti teg t'nod llits I
(Backwards text generator for your amusement:
https://www.prepostseo.com/tool/reverse-text-generator
)
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Stick a fork in it. NSF announced today that extensive damage and dangers associated with repairs combine to form an insurmountable hurdle. The Arecibo Observatory is to be decommissioned in its entirety.
https://www.space.com/arecibo-observatory-radio-telescope-to-be-destroyed?fbclid=IwAR3_1MWNP9vNIJi-QsD8xBz_zOPrxaAsSsu-KiYDds2mkkwviW9-uhg-1Lc
It's a rather undignified end to a long and lustrous career, but the memories are warm and the contributions many.
Brad
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^^^Is there anything to replace it? The VLA in New Mexico?
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I bet it was.... Aliens.
Yeah, my thought. Getting ready to sneak in under the radar, so to speak.
Best way to prep for invasion.
Who had Alians on their 2020 bingo card?
Duh. Ev-ery-body.
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Stick a fork in it. NSF announced today that extensive damage and dangers associated with repairs combine to form an insurmountable hurdle. The Arecibo Observatory is to be decommissioned in its entirety.
https://www.space.com/arecibo-observatory-radio-telescope-to-be-destroyed?fbclid=IwAR3_1MWNP9vNIJi-QsD8xBz_zOPrxaAsSsu-KiYDds2mkkwviW9-uhg-1Lc
It's a rather undignified end to a long and lustrous career, but the memories are warm and the contributions many.
Good grief!
"It is, I think, just truly unfortunate that this main cable failed before we had a chance to get things stabilized," Zauderer said.
Obviously, it would have been much better if they had gotten it stabilized, and then the main cable failed. Then they could start all over with trying to re-stablize it.
What's puzzling to me is the statement that they (the engineers hired to study the problem) don't know what the factors of safety are. I'm an architect, not a structural engineer, but structural engineering is part of the education for architects and, in theory, I am legally allowed to practice engineering when it's ancillary to an architectural design I create. Basically, even for structures such as this that don't slot neatly into building codes with their safety factor requirements, It has been my understanding through fifty years of practice that everything a structural engineer does has established factors of safety. What this suggests to me is that some or all of the original design computations must have been lost, discarded, or destroyed, so the teams reviewing the structure now can't reproduce the calculations to decide what's safe and what's not.
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The one article says that the science platform in the center is... 9 HUNDRED tons?
Holy *expletive deleted*it.
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The one article says that the science platform in the center is... 9 HUNDRED tons?
Holy *expletive deleted*it.
Just a guess, but I figure it was made intentionally heavy for dimensional stability reasons. When you're peering a couple billion light years into the universe, a twitchy instrument platform can kinda be a thing.
Brad
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Good point. I hadn't though of that.
But, I bet when it starts oscillating it takes a LONG time to settle down.
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I'm wondering if what they mean is, that's the total tension required on the cables or something like that.
When one refers to a tightrope walker, that rope has to be really, really tight.
(https://i.ytimg.com/vi/JrdyOcUJ86c/maxresdefault.jpg)
(https://s3.amazonaws.com/images.spaceref.com/news/2019/oooArecibo.jpg)
I've forgotten how to do the calculations (high school, ~1955), but I know that even a small weight on a "tight" "rope" will deflect the rope substantially no matter how "tight" the rope is.
So it seems to me that large number (900 tons) might refer to the suspension cable tensions rather than the weight of the module.
Hawkmoon, what do you think?
Terry, 230RN
Pic credits in properties. The tightrope walker may not be an actual image.
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"When you're peering a couple billion light years into the universe, a twitchy instrument platform can kinda be a thing."
Except, it's a radio telescope, so stability isn't really that critical, I don't think.
I know the big optical telescopes are generally mounted on temperature-controlled floors, often held at freezing, to keep the floor from expanding and contracting and moving the scope. My astronomy professor at college broke his ankle at one of the optical telescopes when he slipped on ice on the floor, even though it was summer out.
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We don't need no stinking radio telescope when all science is settled. That land is much more valuable as a wind or solar panel farm
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I'm wondering if what they mean is, that's the total tension required on the cables or something like that.
When one refers to a tightrope walker, that rope has to be really, really tight.
(https://i.ytimg.com/vi/JrdyOcUJ86c/maxresdefault.jpg)
(https://s3.amazonaws.com/images.spaceref.com/news/2019/oooArecibo.jpg)
I've forgotten how to do the calculations (high school, ~1955), but I know that even a small weight on a "tight" "rope" will deflect the rope substantially no matter how "tight" the rope is.
So it seems to me that large number (900 tons) might refer to the suspension cable tensions rather than the weight of the module.
Hawkmoon, what do you think?
Terry, 230RN
Pic credits in properties. The tightrope walker may not be an actual image.
You are correct, it doesn't take much weight to deflect the cable. But that doesn't mean the cable tension increased all that much. I used to know how to figure that... (Disclaimer: I made a D in that class in college)
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Eh. I don't get all the fuss. What's a hundred foot hole to a mile wide dish? :old:
Woody
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Eh. I don't get all the fuss. What's a hundred foot hole to a mile wide dish? :old:
Woody
It's pretty much falling apart and considered unsafe to attempt repairs
Worlds Largest Radar Astronomy Dish To Be Demolished!
https://www.youtube.com/watch?v=IEe4Wlc5Vp0
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Woody, you're right about the size of the hole. After all, they originally set it up as a spherical mirror and could correct for spherical aberrations by positioning the pod, so by comparison, it's sort of like a dust mote on your camera lens.
The problem (as I see it) is the fact that a cable broke and re-suspending the pod is beyond reasonable feasibility.
And looking at the suspension system in the aerial view, calculating those multiple cables would be a nightmare, and no wonder they were looking for the original calculations and specs for that.
(I would liken it to the complexities of calculating a three-element compound lens. Any change of any element's refractive index, gapping between lenses, or a bit of curvature change and you've got to start all over.)
While the actual number-crunching could be done by computin' engines nowadays, it sounds like nobody knows how they set up the parameters any more.
And I guess most of the valuable results have already been obtained, so it ain't worth it.
That's my take on it anyhow.
Terry
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Woody, you're right about the size of the hole. After all, they originally set it up as a spherical mirror and could correct for spherical aberrations by positioning the pod, so by comparison, it's sort of like a dust mote on your camera lens.
Tje peoblem (as I see it) is the fact that a cable broke and re-suspending the pod is beyond reasonable feasibility.
And looking at the suspension system in the aerial view, calculating those multiple cables would be a nightmare, and no wonder they were looking for the original calculations and specs for that.
While the actual number-crunching could be done by computin' engines nowadays, it sounds like nobody knows how to set up the parameters any more.
And I guess most of the valuable results have already been obtained, so it ain't worth it.
That's my take on it anyhow.
Terry
Even tho' I made a D in that class 40 years ago, I could probably figure it out. Sad! ;) Whether it's worth fixing is an interesting question.
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Woody, you're right about the size of the hole. After all, they originally set it up as a spherical mirror and could correct for spherical aberrations by positioning the pod, so by comparison, it's sort of like a dust mote on your camera lens.
The problem (as I see it) is the fact that a cable broke and re-suspending the pod is beyond reasonable feasibility.
And looking at the suspension system in the aerial view, calculating those multiple cables would be a nightmare, and no wonder they were looking for the original calculations and specs for that.
(I would liken it to the complexities of calculating a three-element compound lens. Any change of any element's refractive index, gapping between lenses, or a bit of curvature change and you've got to start all over.)
While the actual number-crunching could be done by computin' engines nowadays, it sounds like nobody knows how they set up the parameters any more.
And I guess most of the valuable results have already been obtained, so it ain't worth it.
That's my take on it anyhow.
Terry
Yeah, I get that too.
This reminds me of the miscalculated shape of the mirror on the Hubble Telescope that rendered it nearly unusable. I'm glad they were able to surmount it, though. It has contributed much to our knowledge just like Arecibo. With the advancements in drones and calculating prowess, maybe a little more can be squeezed out of Arecibo sort of like how they can send out a laser beam from the giant optical telescopes and calculate and flex the mirror(s) to compensate for atmospheric aberrations.
On an anecdotal note, I hope they used better cables on the Golden Gate Bridge ...
Woody
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Well, things age just sitting there. And they had a couple of goodly hurricanes over the decades. I guess you can design for a hurricane, but I don't know how you design for N hurricanes.
I wonder, too, about the day-to-day economy of the surrounding area now that it will be closed down. Maybe a tourist attraction? But how many touristas might actually be interested in seeing it now.
Plug up the drains and fill it as a swimming hole?
Terry, 230RN
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Well, things age just sitting there. And they had a couple of goodly hurricanes over the decades. I guess you can design for a hurricane, but I don't know how you design for N hurricanes.
I wonder, too, about the day-to-day economy of the surrounding area now that it will be closed down. Maybe a tourist attraction? But how many touristas might actually be interested in seeing it now.
Plug up the drains and fill it as a swimming hole?
Terry, 230RN
Put it up for sale. Someone will buy it.
Woody
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Put it up for sale. Someone will buy it.
Woody
If you tack on the Brooklyn Bridge as a free add-on it will sell faster ..... [tinfoil] [popcorn] ......... =D
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It's pretty much falling apart and considered unsafe to attempt repairs
Worlds Largest Radar Astronomy Dish To Be Demolished!
https://www.youtube.com/watch?v=IEe4Wlc5Vp0
And supersized dishes have been supplanted by distributed arrays. The big dish in question is also more limited in its field of view than a comparable array telescope.
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OK, looks like I was wrong... They really do focus that thing in...
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Gravity saved them the expense of demolition. Catastrophic cable failure early this morning. The mighty Arecibo dish is gone.
(https://www.sciencemag.org/sites/default/files/styles/article_main_image_-_1280w__no_aspect_/public/arecibo_1280p_0.jpg?itok=ASgBntK7)
https://www.sciencemag.org/news/2020/12/arecibo-telescope-collapses-ending-57-year-run
https://www.youtube.com/watch?v=vchDbyIRP44
Double-unfortunate is the failure appears to have destroyed the cable decks on all three suspension towers, ending any hope of using the towers for future re-instrumentation.
Brad
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If they patch the holes they might be able to get a swimming pool out of it ..... [tinfoil] [popcorn]
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Wonder if it still gets the playboy channel
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Nature always wins in the end.
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Has anyone blamed Orange Man yet?
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Rub some dirt on it. It will be fine.
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. . . I would liken it to the complexities of calculating a three-element compound lens. Any change of any element's refractive index, gapping between lenses, or a bit of curvature change and you've got to start all over. . . .
Lenses like the Cooke Triplet (patented in 1893) are today considered simple - almost trivial. Whereas the old timers had to be really clever and rely on things like log tables and mechanical calculators, the programs that run on today's desktop computers allow a skillful optical engineer to move FAR beyond triplet lenses, and include things like aspheric surfaces, holographic optical elements, and gradient index materials.
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Well, things age just sitting there. And they had a couple of goodly hurricanes over the decades. I guess you can design for a hurricane, but I don't know how you design for N hurricanes.
I wonder, too, about the day-to-day economy of the surrounding area now that it will be closed down. Maybe a tourist attraction? But how many touristas might actually be interested in seeing it now.
Plug up the drains and fill it as a swimming hole?
Terry, 230RN
Another skip-poster:
If they patch the holes they might be able to get a swimming pool out of it ..... [tinfoil] [popcorn]
It's OK, I do that myself sometimes. Just amusing to find I'm not the only one.
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If they put a liner over it, that would be an awesome spot for a giant swimming pool.
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If they put a liner over it, that would be an awesome spot for a giant swimming pool.
Holy cow, Ben. Anyone else want to extend the swimming hole concept?
Lenses like the Cooke Triplet (patented in 1893) are today considered simple - almost trivial. Whereas the old timers had to be really clever and rely on things like log tables and mechanical calculators, the programs that run on today's desktop computers allow a skillful optical engineer to move FAR beyond triplet lenses, and include things like aspheric surfaces, holographic optical elements, and gradient index materials.
Oh, I'm pretty much aware of that. But having a machine programmed to do the number-crunching does not change the complexities involved. It's like saying the Roman Aqueduct or the Coliseum was easy to build because you had slaves to carry all that masonry up and down.
Somebody still had to work out the VLI + IV = L versus VLI + V = LI stuff in the first place.
Terrigula, CCXXX RN
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If they put a liner over it, that would be an awesome spot for a giant swimming pool.
Yeah, liner! It would definantly require that!!! =D I love you guys! :lol:
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Could rhey stock it with bass? The locals could make money renting bass boats and bass equipment for bass fishing contests. Or would the water be too warm?
(https://i.ytimg.com/vi/z71_lV1RxdA/maxresdefault.jpg)
The trouble with making it a pool is there'd be no shallow end. It's all deep end unless they put in artificial beaches. You could lose a lot of little kids that way.
Pic credit in properties
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Could rhey stock it with bass? The locals could make money renting bass boats and bass equipment for bass fishing contests. Or would the water be too warm?
(https://i.ytimg.com/vi/z71_lV1RxdA/maxresdefault.jpg)
The trouble with making it a pool is there'd be no shallow end. It's all deep end unless they put in artificial beaches. You could lose a lot of little kids that way.
Pic credit in properties
I think stock it with mermaids for all us redneck "anglers".
Woody
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Heard they were just getting ready to announce they had picked up transmissions from Hillary's computer
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I think stock it with mermaids for all us redneck "anglers".
Woody
(https://live.staticflickr.com/65535/50671777343_b8b7e803fa_z.jpg) (https://flic.kr/p/2kcG72v)
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Videos of the collapse
https://twitter.com/thesheetztweetz/status/1334536362893189125
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Izzat fer real, or one of those computer-generated scenes which always fool me?
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Izzat fer real, or one of those computer-generated scenes which always fool me?
Seems to be real. It's on YouTube, too -- which is nice because you can slow it down to watch the cables failing in slo-mo.
https://www.youtube.com/watch?v=b3AASKr_iHc
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Seems to be real. It's on YouTube, too -- which is nice because you can slow it down to watch the cables failing in slo-mo.
https://www.youtube.com/watch?v=b3AASKr_iHc
Deferred maintenance in jungle conditions is no bueno. Watching the steel cables break strands before parting completely is total nightmare fuel.
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There are times I have to wonder whether I'm a bigger fool for accepting fake reality or for questioning the reality of real stuff.
'Tis a puzzlement.
Terry, 230RN
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Guys, guys! 2 words, Flex Seal!
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We're going to need a bigger roll of duct tape
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We're going to need a bigger roll of duct tape
And paracord. With duct tape and paracord, the possibilities are endless.
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So I learned that while Arecebo is obsolete as a radio telescope it is still our best space radar. That sounds worthwhile to rebuild.
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And paracord. With duct tape and paracord, the possibilities are endless.
DETCORD!!!!! Just get it over with! >:D
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DETCORD!!!!! Just get it over with! >:D
I don't think detcord has the necessary tensile strength to support the necessary equipment.
But I'm willing to give it a shot.
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I don't think detcord has the necessary tensile strength to support the necessary equipment.
But I'm willing to give it a shot.
=D I don't think that's how you use detcord .... :facepalm: ;)
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They could try rebuilding with a single concrete tower in the middle holding up the receiver arrays. Might be better than steel wire in that environment. It gives up a little in the FoV but is probably the cheapest and thus most likely to happen if anything does.
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Only a couple of minutes into this but I didn't know it was originally built to detect nuclear explosions
The Arecibo Radio Telescope with Prof. Abel Mendez
https://www.youtube.com/watch?v=L59G29iufWI
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Heard they were just getting ready to announce they had picked up transmissions from Hillary's computer
The theory is they were reflected back from the Dark Matter out there.
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Failure analysis report update.
https://www.youtube.com/watch?v=3oBCtTv6yOw
Brad
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Failure analysis report update.
https://www.youtube.com/watch?v=3oBCtTv6yOw
Brad
*prediction before watching* Lack of maintenance plus corrosion, exacerbated by a strong storm.