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TheGreatCoyote t1_iy7xjtw wrote

Reply to comment by padizzledonk in Photo shows 3 stowaways who were rescued from oil tanker's rudder after likely 11-day ordeal by grungegoth

Yeah, youre not floating away if you fall off the rudder of a ship under way. You're getting drawn into the props and chopped up into fine fish food.

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NextTrillion t1_iy94px7 wrote

Lol no, the rudder is behind the prop, which propels the ship with enormous force. That force would thrust you much further away from the prop and the ship in general, likely tossing you about like a rag doll for a good while. There may be circulating back currents, but I doubt they’d be strong enough to overcome the thrust of the prop. There are few engines on the planet more powerful than these.

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GozerDGozerian t1_iybqiob wrote

Your for sure drown in the prop wash, right? All that massive turbulent water half mixed with air wouldn’t be something even the best swimmer could stay afloat in I’d imagine.

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feral_brick t1_iyc6bt8 wrote

Actually it's not as bad as you'd think... Turbulence in a situation like that a trivial factor, the tendency is to either stay in the flow (where your relative velocity is low) or get kicked out of it. Unless you're trying you're pretty much guaranteed not to stay at the interface of the prop wash.

And aeration from a point source like that is very much a function of water velocity, and the air bubbles tend to rise pretty quickly. So if you look behind a motor boat you might see a long trail of bubbles but the length is mostly because they get pushed far out, not that they take a long time to rise

With a pfd, if you had the foresight to hold your breath, I'd say it's pretty much a guarantee that you'd survive. So in context is just a question of whether they got caught off guard and got unlucky with their breath, or of they got disoriented.

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GozerDGozerian t1_iyc6flq wrote

I see. Thanks for the well thought out response! Think I’ll still steer clear of rudder sitting though. :)

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codedigger t1_iy8h5qk wrote

Would think individual would float as past the props and ship moving forward. Not sure on fluid dynamics of props and if they suck water from behind them but would think that would be inefficient and engineers would have found a better design.

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