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Someone with more engineering sense than I can debunk this: The Baltic is dramatically less saline than the Atlantic. That's why the Vasa [1] was so well-prese
by AlbertCory 4y ago
Someone with more engineering sense than I can debunk this:
The Baltic is dramatically less saline than the Atlantic. That's why the Vasa [1] was so well-preserved after 300 years at the bottom.
So could we not take advantage of that salinity difference, somehow?
[1] https://www.vasamuseet.se/en https://www.vasamuseet.se/en
Edit: Every engineering student sees the movie of the Tacoma Narrows bridge collapsing. To me, the Vasa is a much better career lesson: Marketing dictating a stupid Engineering decision.
"Hey, let's put another gun deck on that thing! It'll be so much more imposing."
- mongol 4y agoIt is not the salinity as such that protected Vasa, but the absence of the ship worm, which does not like the Baltic brack water.
- AlbertCory 4y agoTIL. I did go to that museum and I thought that was what they said. What do you mean by "brack water"?
- chucksmash 4y ago> Brackish water, sometimes termed brack water, is water occurring in a natural environment that has more salinity than freshwater, but not as much as seawater. > Some seas and lakes are brackish. The Baltic Sea is a brackish sea adjoining the North Sea. https://en.wikipedia.org/wiki/Brackish_water https://en.wikipedia.org/wiki/Brackish_water
- mongol 4y agoBrack water have a salinity between sea water and fresh water.
- caseysoftware 4y agoI visited the Vasa museum in late 2019 and it was stunning. Not just how well it had been preserved but how few people died in it. They noted that one of the biggest contributors to its preservation was simply the location: since it had barely left the harbor, it was shielded from most storms and buried in mud in relatively shallow water. Even better, when it sank, the Vasa was still just a few hundred feet from shore so only a few dozen people died instead of the hundreds onboard.
- FiatLuxDave 4y agoWe could. The technology you would use for this is https://en.wikipedia.org/wiki/Osmotic_power https://en.wikipedia.org/wiki/Osmotic_power . Unfortunately, it is not currently cost-effective. The salinity of the Baltic varies but is generally below 13 g/kg, which is a lot less than the salinity of the Atlantic (around 35 g/kg). This corresponds to an osmotic pressure differential around 1.8 kJ/L (1.8 MPa). If you were to build a dam which had a gravity pressure which matched this pressure differential it would be about 180 m high. So, yes, there is plenty of energy in that salinity difference, but getting it out in a cost effective manner is an open problem.
- AlbertCory 4y agoExcellent. Thanks!
- simonh 4y agoWe beat you by over 80 years with the Mary Rose, although she at least managed to get into battle before she went over.
- AlbertCory 4y agoTIL the Mary Rose. [1] doesn't say for sure it was top-heavy, though. "Marsden has suggested that the weight of additional heavy guns would have increased her draught so much that the waterline was less than one metre (c. 3 feet) from the gunports on the main deck." gosh, you'd think someone would have noticed that. [1] https://en.wikipedia.org/wiki/Mary_Rose https://en.wikipedia.org/wiki/Mary_Rose
- jvdvegt 4y agoThey use exactly this in De Afsluitdijk in The Netherlands [1], which seems to use technology from redstack [2]. [1] https://www.rijkswaterstaat.nl/zakelijk/duurzame-leefomgeving/energie-en-klimaat/icoonprojecten-energie-en-klimaat/afsluitdijk-energiedijk https://www.rijkswaterstaat.nl/zakelijk/duurzame-leefomgevin... [2] https://redstack.nl/en/ https://redstack.nl/en/?