I wonder what engineering challenges are involved in this. I'd imagine it's more complicated than just digging a bigger hole and adding more water filters
Leaks. Water at those pressures finds holes, opens cracks and eats away at foundations. A little trickle quickly becomes a sinkhole, or your structure starts to float away. It all depends on the soil.
Challenges are probably not so big once the thing is constructed. External earth and groundwater pressure offsets internal water pressure I would assume and the real challenge is actually designing for when the thing is empty so that it doesn’t fail due to external loads.
Lots of this is dependent on geology of the adjacent soil and geometry of the hole. Pictures seem to show sheet piles so we know it’s soil.
Polish orthography looks insane to native English eyes, but spending a couple hours studying when I was over there 3 years ago was enough to guess right. More sensible than English orthography I'd say!
Odd, I don't speak Polish, but my mom and grandparents did. Even that small exposure was enough for me to get that pronunciation 100% correct. I wonder what the minimum exposure to any given language is to allow someone to correctly guess pronunciation. I speak a little German and French but regularly get the pronunciation incorrect, but I didn’t grow up around native German and French speakers.
Polish pronunciation is actually incredibly easy, there's a direct mapping (a mathematical function) from a simple partition of letters to phonems. Unlike in English, where we have weirdnesses like "vehicle" or "colonel". There's a price to pay for quick and massive import of words, lack of centralized language development coordination body and conquering the global stage of accents, I reckon.
Example for the town: Mszczonów -> Mshchonooff (Americanized).
The "v" at the end can get devoiced to "f" in casual speech, but people don't think of it as "f", because in other forms of the word, where it has postfixes - it still has to be pronounced as "v".
That is generally more of a recommendation. The recreational diving limit is generally considered to be 130ft, as that's the depth you can't spend more than a few minutes at without incurring mandatory decompression (breathing air).
You can take a deep diving course if you like, but not everyone bothers. Going below 130 though becomes a technical and very complex endeavour quickly.
People imagine that diving training agencies has police power to allow or forbid you to do something. That's not true.
When you get a certification, the agency certifies that you have been trained to go to 18m. That's all it does.
After the training you can do whatever you want. But if you're not stupid and don't want a quick death or a painful life (wheelchaired due to bends), you will stay within the limits of your training.
So it's not only a recommendation, but at the end it works like one.
Looking it up, you're right, and the Advanced Open Water says 30m max. I don't know if it changed or if I just misremembered. I'm pretty sure I did 40m as part of the deep diving segment of Advanced Open Water, but that might not be accurate either. It was about 10 years ago.
I never met instructor who was very fond of keeping strict limits as per our current certification, I guess those folks are rather laid back and don't care about some rules that much.
I recall when doing my original SSI Open water cert in Croatia (max should be 18m), the instructor took us to 33m, it was maybe 4th dive in the course (and in my life). I was a bit worried and showed him the depth meter, he just signaled back OK, so I went along (like I could do anything else at that moment).
When training for Advanced OW, or diving after I obtained it in various places, nobody cares about precise limit (should be cca 30m for SSI IIRC), generally 35-40m is the limit for real dives.
At least they all rigorously follow decompression stops on a way up, wrist computers help greatly with more precise measurements. You just need to stick to +- same depth as instructor, not be constantly 5m below him chasing creatures.
Dive computers will give you precise instructions, but they aren't necessarily accurate. Many people fail to appreciate the difference between precision and accuracy.
> I don't know if it changed or if I just misremembered.
I'm pretty sure it changed.
Back when I did PADI OW on Grand Cayman in the early 90s, I did the course under a course director (apparently some sort of god within the hierarchy according to another instructor I chatted with years later). We learned that 40m was the limit and went down that far.
It's only years later on 'refresher' courses that I've learned both that I wasn't officially qualified to dive beyond 18m (being an OW only, not AOW), and that 30m is considered the recreational limit these days, with 40m as a sort of hard limit. In the 90s and early 00s I did deep dives, wreck dives, cave dives and all sorts on the basic qualification! Always with instructors, but still... I feel both privileged and hugely underqualified to have done that cenotes dive on the yucatan peninsula...
I've done a deep-dive speciality and an enriched air speciality since then. I must get my Advanced one of these days!
I've done a couple cenotes and a couple wrecks, also with an experienced dive master. AOW isn't really very "advanced". It's doable in 3 days, with some prework. Such was the case for me, and I got it like a week after getting my OW. So you're probably a lot more advanced than me by any real measure!
Did you do proper cave dives? I've only did caverns (within site of daylight) in the cenotes, which was enough of a thrill for me.
Yeah, I did two fully enclosed cave dives into the dark. We were following a line laid by the dive master, and he was clearly very experienced and lead the group (me and one other guy) slowly and calmly. We learned a low-turbulence way of propelling ourselves around before we went, so we didn't kick up too much dust in the tighter spots, and how to attract his attention with the torch.
It was stunning, we swam through some huge, completely submerged caverns, and through some small connecting passages with submerged limestone cavern features. We also surfaced in a bat cave at one point on the first dive. This was somewhere around Playa Del Carmen.
Just happy I was young enough at 22-ish not to really think about the risks :)
I don’t believe so, especially given how dangerous it is. Several died a few years back and policies became even more restrictive. It’s other name is the Underwater Explosive Testing Facility.
Near the bottom there's a picture of a different pool, the current largest. A "mermaid" is swimming around without scuba gear. Here is a video I found about that:
I know, right? For now, you have to know somebody who knows somebody who knows Kelly. :-)
Word is that they're going to start opening up reservations for full-day events, sometime this year. Maybe $30k for the day (but that's just a guess). One wave every four minutes. 7 hours in the day. You can bring a dozen friends and surf until your arms (and legs, because the rides can be a full minute long) are noodles. Or you can bring 30 friends and still get eight or ten waves for the day.
After being lucky enough to tag along to a group that surfed there last year, I've spent a ridiculous amount of time thinking about what my income level would have to be for the $30k to seem like a "reasonable" outlay, once a year. The answer is "a lot lower than is sensible." It's a clean, head-high face, a super-fast down the line wave, and two legit barrel sections. Better than the best waves anywhere on the California coast outside of a handful of days a year.
Of course, $30k is just the entry level option. They are starting to think about licensing the plans and tech. For maybe $10M you could build your own! (No idea what it costs to run it per year.)
That article is out of date. It’s still operational and in use. Policies changed after three deaths in close succession. Still, the point is that manmade pool exists and has for years contrary to the article.
As someone who is unfamiliar with the area, are you being facetious, or is the natural geography particularly well-suited to building a pool of this sort?
In the UK, "a hole" means that a place is bad. I think you could probably translate this into more international English by making a similar pun on "Colchester is already a dive", but it doesn't work quite as smoothly.
Secondly, Colchester is a principal part of Essex, which vies with Newcastle for being the UK's New Jersey, but in a worse way than Newcastle. Wikipedia has several articles on the pejorative Essex stereotypes. Colchester also has a major military base, which makes it a center for squaddies[0].
Imagine playing vertical scuba american football in 100 meters of water.
I think the end zone would always have to be at the bottom, and with direction of play as a constant, sides would change with possession. Except for punting. Kicking would have to follow the direction that the ball tries to float in.
Playing a vertical game of football underwater would be very difficult, and likely hazardous.
1. As anyone who's gone diving will attest, you physically can't dive very quickly. You have to constantly equalize your ears as you descend to avoid pain. This would limit how fast you can go down. (Especially at shallower depths, where the effect is more pronounced.)
2. At deeper depths, you'll quickly hit your no-decompression time limits. At 40 meters depth, you only have 8 minutes of no-decompression time. And that's if you don't run out of air first.
3. Recreational diving is usually limited to 130 feet / 40 meters - and that's with extra training. At deeper depths not only does nitrogen have a narcotic effect, but oxygen quickly becomes toxic. A 100 meter dive is well within the realm of technical (not recreational) diving and would require special breathing gas and careful planning.
4. Rapidly going up and down, like you'd need to play a game of football, is recipe for giving yourself the bends. You need to ascend slowly. (And again, that's assuming you haven't exceeded your no-decompression time.)
On the other hand, you could play a horizontal game just fine. You're practically weightless underwater (at neutral buoyancy), so the game would be the same the same either way. (For Ender's Game fans: "The enemy's gate is down.")
How about playing football whilst free diving and so avoid the joys of gas bubbles forming. The current free dive depth record is something around 250 meters and people who do free diving spear fishing frequently dive down to 20 - 30 meters.
It would change the game somewhat but I could imagine having a ball that was buoyant at about 10 meters would force the play underwater. Having the goals on the bottom either side of a submerged wall would force vertical movement.
You would have a challenge with viewing the action, but there are some pretty amazing underwater drones around so I think you could really get with the action.
Apnea is all about conserving energy, moving as less as you can and as efficient and you can.
That said, have you ever watched an apnea competition? When reaching the surface, athletes are required to say "I'm Ok" and do a sign with their hands. Some times they can't do that because they're in a hypoxia state and very close to pass out. it's not a situation you want in a contact sport.
