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New study sheds light on 'dead water' phenomenon -- Sott.net:
Norwegian mariners called it dødvann — dead water. They'd known for centuries that patches of seawater in narrow fjords could mysteriously sap a ship's speed, drastically slowing it or stopping it altogether. In his 1897 book, Farthest North, explorer Fridtjof Nansen wrote of his encounter with dead water north of Siberia in 1893: "We could hardly get on at all for the dead-water, and we swept the whole sea along with us." Dead water, Nansen noted, occurred "where a layer of fresh water rests upon the salt water of the sea," as happens in northern fjords when snow and ice from mountains melt into the ocean.[Emphasis from original article - Ed]
Nansen's report of dead water was investigated by scientists at the time, including the Swedish oceanographer Vagn Walfrid Ekman. In 1904, Ekman published research that showed dead water was caused by hidden waves in a dense subsurface layer of salt water that slowed the forward motion of a ship. Today's speedy ships easily overcome these submerged waves, and for most mariners dead water is now largely forgotten.
But more than 100 years later, scientists are still exploring the phenomenon, and a new investigation has uncovered more details about its underlying mechanics.
Journal Reference:
Johan Fourdrinoy, Julien Dambrine, Madalina Petcu, et al. The dual nature of the dead-water phenomenology: Nansen versus Ekman wave-making drags [$], Proceedings of the National Academy of Sciences (DOI: 10.1073/pnas.1922584117)
(Score: 0) by Anonymous Coward on Sunday October 04 2020, @09:17PM
Nye the Science Guy!
This is a decent example of why it is good to have scientists with enough free time to pursue random research. Might never be actually useful, but it is awesome to explain long standing mysteries.
(Score: 2) by fakefuck39 on Sunday October 04 2020, @09:50PM (6 children)
fresh water is less dense - the boat would speed up, not stop.
"hidden waves in a dense subsurface layer of salt water" sounds like a load of crap - a wizard did it
(Score: 1, Informative) by Anonymous Coward on Monday October 05 2020, @01:18AM
The ships energy goes into make internal waves at the boundary layer between the fresh and salt water.
(Score: 1, Interesting) by Anonymous Coward on Monday October 05 2020, @06:11AM (2 children)
Fresh water is less dense, the boat would be cruising along and suddenly sink lower in the water increasing the drag.
(Score: 2) by fakefuck39 on Tuesday October 06 2020, @05:04AM (1 child)
that's absolutely true. what's your point though? ships go faster in freshwater. this is a fact. the total volume of water that needs to be moved is more. the total weight is less.
(Score: 0) by Anonymous Coward on Tuesday October 06 2020, @10:07AM
If the transition is sharp enough the boat would sink past equilibrium resulting in a short-term increase in drag. It would feel like the ship ran into something, hence the solid water thing.
(Score: 0) by Anonymous Coward on Tuesday October 06 2020, @05:53PM (1 child)
...why are you trolling? TFA is very clear and your comment doesn't reflect it.
(Score: 2) by fakefuck39 on Tuesday October 06 2020, @06:13PM
Disagreeing with the article and questioning its finding is trolling? ok retard. the article says waves between the salt and freshwater layer, unlike all other kind of waves the ship regularly encounters, stop the ship and prevent it from moving forward in a medium that makes moving forward easier.
this sounds like a bunch or crap to me. there is zero actual evidence or observations in the article - just this theory.
why are you replying to me? you contributed literally zero of content, and since you're not logged in, we don't even know who the autistic retard here is so we can't laugh at you. well, we can.
(Score: 3, Informative) by Anonymous Coward on Sunday October 04 2020, @11:08PM (1 child)
This article is from a pseudoscience website. It's all COVID denier, intelligent design and occasional white supremacist nonsense.
However, the journal reference is credible.
(Score: 0) by Anonymous Coward on Monday October 05 2020, @01:21AM
Is this like smart water?