While down from its peaks, Duluth is still a very active harbor. [1]
There are regular harbor cams and freighter watching videos on Youtube. [2][3]
There is an old lake freighter open to tour. [4]
There are several good breweries (probably better quality than what would have been available peak Duluth!).
The University of Minnesota does have historical aerial survey photos of the port starting in the 1930s, but modern Google Maps satellite is probably better to get a sense of the port. [5]
If you travel up the north shore, Two Harbors is also still an active port. There's a good brewery there. And still further up the coast, there's also an old lighthouse that can be toured. [6]
Not a local, just a fan. But as a fan of history, I agree it would be so interesting to time travel.
This is what I feel is a killer usecase for the "metaverse" or VR in general - especially as an educational tool.
People who've tried certain VR experiences know it's SUPER immersive (seriously, I had a physical adrenaline spike when I was on the edge of a platform hundreds of meters up in Vader immortal) - having that kind of experience in an educational setting is going to cause those experiences to embed, and with them, the subject being learned, far better than any book for some people.
> go back in time and see some of these remote port cities in their heyday
It would be a sight to see. For scale, in the 1860s and 1870s Chicago was the busiest port in the US; "In 1871, more ships arrived [in Chicago] than New York, San Francisco, Philadelphia, Baltimore, Charleston, and Mobile combined" [1]. I imagine that Marquette or Duluth would have a top-10 busiest port in the US at that time - where else would all those ships be coming from?
There's a very intriguing podcast episode by Stuff You Should Know about the Edmund Fitzgerald. I would definitely recommend giving it a listen to anyone who is interested in the story of the wreckage.
They also touched on how Lightfoot modified the lyrics in his song to reflect new findings, which was a very kind thing of him to do, especially when you consider that many families lost loved ones in the tragic accident.
If you are interested in this make sure you check out Fathom Five Provincial Park in Ontario (on the Bruce Peninsula that separates Lake Huron from Georgian Bay.
It's an awesome dive location and enough pristine wrecks to keep you fascinated for a long time.
assuming it's in similar range, that's serious depth. Way into hypoxic trimix zone (ie: you'll be breathing gas that'd kill you if you were breathing it on the surface)
Looks fascinating, but almost certainly out of reach for all but the most extreme technical divers.
I’m not a diver; but the physiology of these depth effects is fascinating! TIL that these hypoxic mixes are needed because of a combination of two effects: nitrogen narcosis[0] and oxygen toxicity[1]. The former is due to diffusion of any gas, apart from helium, into neurons in the CNS under high pressure, while the latter is due to the raised partial pressure of O2 at depth. 100% O2 is cumulatively toxic at sea level, but at depth its toxicity is enhanced at what would be a normal 21%. At least that’s my layman’s understanding.
In diving we think in terms of partial pressures. At sea-level, 21% of air is oxygen, and .21 is also your partial pressure of O2. In order to breath at depth, though, we need to be supplied with a higher and higher pressure of gas to fight the pressure of the surrounding environment opposing our lung expansion. At 10 meters, the pressure doubles sea-level, and you are breathing gas at twice atmospheric pressure (meaning there are twice as many O2 and Nitrogen molecules in every liter of gas).
Consequently, the partial pressure of oxygen you are breathing is doubled, to .42. This continues, until you reach a partial pressure which is incompatible with life. That danger-zone is generally considered to be between 1.4 and 1.6, so air cannot be safely breathed below about 60 meters (1.6/.21 - 1 = about 6 atmospheres). Similarly, pure O2 cannot be breathed safely below about 6 meters (1.6/1 - 1 = about .6 atmospheres).
Your description of nitrogen narcosis is correct. To dive deeper than your nitrogen narcosis limits you start replacing some of the nitrogen with helium in the gas you breathe. This works up to the limits of even the most technical recreational diving, after which you will get symptoms of something called HPNS which could mean replacing the helium itself with hydrogen.
Both helium and nitrogen will get stored in your inert tissues and will bubble out catastrophically if you ascend too quickly. With either inert gas you must carefully plan your ascent to avoid the bends.
> Both helium and nitrogen will get stored in your inert tissues and will bubble out catastrophically if you ascend too quickly.
I'm not going to link to the Byford Dolphin incident, because it would need a [TW] and I hate that shit, so you can just google it yourself. The 30-second rundown is that on the surface divers live in a very strong steel tank pressurised to the same degree as they would be on the seabed, so maybe make sure you close the door properly.
If you're interested in the physiology of respiration at the limits this lecture by John West is fantastic https://www.youtube.com/watch?v=QRN124iuqZ8 . It has been some time since I watched it in med school but if I recall correctly, I think it is pretty accessible to anyone who is technically/scientifically minded.
The big thing to understand is that you gain a whole atmosphere of pressure every 10 meters underwater you go. So at 100 meters you are experiencing 11 atmospheres of pressure (over 150 PSI). It's a wonder humans can go there at all without a vessel!
It's not really about the distance; it's about how drastically conditions change in 100m depth of water -- to the point that very specialized equipment is necessary for humans to survive, and if we're not careful on the way up it's gonna be a Very Bad Time possibly (or even likely) resulting in death.
For sure. This got me thinking about how humans need special equipment to survive long even 1m below the surface, and the problems just get worse with depth. Wikipedia has nice coverage of the way we've iterated deeper and deeper: https://en.wikipedia.org/wiki/History_of_underwater_diving
> DCS [Decompression Sickness] is best known as a diving disorder that affects divers having breathed gas that is at a higher pressure than the surface pressure, owing to the pressure of the surrounding water. The risk of DCS increases when diving for extended periods or at greater depth, without ascending gradually and making the decompression stops needed to slowly reduce the excess pressure of inert gases dissolved in the body.
> Decompression time can be significantly shortened by breathing mixtures containing much less inert gas during the decompression phase of the dive (or pure oxygen at stops in 6 metres (20 ft) of water or less). The reason is that the inert gas outgases at a rate proportional to the difference between the partial pressure of inert gas in the diver's body and its partial pressure in the breathing gas; whereas the likelihood of bubble formation depends on the difference between the inert gas partial pressure in the diver's body and the ambient pressure. Reduction in decompression requirements can also be gained by breathing a nitrox mix during the dive, since less nitrogen will be taken into the body than during the same dive done on air. [85]
>> almost certainly out of reach for all but the most extreme technical divers.
Diving that deep isn't going to become easier anytime soon. But have a look at the consumer-grade "underwater drones", formerly called ROVs. I wouldn't be surprised to see people in small boats doing youtube videos of such wreaks in a couple years.
Eg, little unstable thing tethered to larger, more stable thing?