Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > sci.physics > #540713 > unrolled thread

Does a capital ship sinking actually SUCK a swimmer down to drown?

Back to article view | Back to sci.physics

Contents

  Does a capital ship sinking actually SUCK a swimmer down to drown? "M. Stradbury" <mstradbury@example.com> - 2015-12-22 00:04 +0000
    Re: Does a capital ship sinking actually SUCK a swimmer down to drown? Tony Hwang <dragon40@shaw.ca> - 2015-12-21 18:51 -0700
      Re: Does a capital ship sinking actually SUCK a swimmer down to drown? Micky <NONONOmisc07@bigfoot.com> - 2015-12-21 20:58 -0500
      Re: Does a capital ship sinking actually SUCK a swimmer down to drown? Sam E <why.should.this@be.email.invalid> - 2015-12-21 22:10 -0600
      Re: Does a capital ship sinking actually SUCK a swimmer down to drown? "M. Stradbury" <mstradbury@example.com> - 2015-12-22 04:31 +0000
        Re: Does a capital ship sinking actually SUCK a swimmer down to drown? "Bob F" <bobnospam@gmail.com> - 2015-12-22 08:19 -0800
          Re: Does a capital ship sinking actually SUCK a swimmer down to drown? Poutnik <poutnik4nntp@gmail.com> - 2015-12-22 17:45 +0100
            Re: Does a capital ship sinking actually SUCK a swimmer down to drown? "taxed and spent" <pleasedonot@spamme.com> - 2015-12-22 09:39 -0800
          Re: Does a capital ship sinking actually SUCK a swimmer down to drown? Micky <NONONOmisc07@bigfoot.com> - 2015-12-23 03:08 -0500
            Re: Does a capital ship sinking actually SUCK a swimmer down to drown? dvus <dven1@adelphia.net> - 2015-12-23 05:23 -0500
              Re: Does a capital ship sinking actually SUCK a swimmer down to drown? Poutnik <poutnik4nntp@gmail.com> - 2015-12-23 12:27 +0100
            Re: Does a capital ship sinking actually SUCK a swimmer down to drown? "Bob F" <bobnospam@gmail.com> - 2015-12-23 05:40 -0800
    Re: Does a capital ship sinking actually SUCK a swimmer down to drown? Micky <NONONOmisc07@bigfoot.com> - 2015-12-21 20:56 -0500
      Re: Does a capital ship sinking actually SUCK a swimmer down to drown? Tony Hwang <dragon40@shaw.ca> - 2015-12-21 19:02 -0700
        Re: Does a capital ship sinking actually SUCK a swimmer down to drown? Micky <NONONOmisc07@bigfoot.com> - 2015-12-21 22:13 -0500
          Re: Does a capital ship sinking actually SUCK a swimmer down to drown? Tony Hwang <dragon40@shaw.ca> - 2015-12-21 20:47 -0700
            Re: Does a capital ship sinking actually SUCK a swimmer down to drown? Micky <NONONOmisc07@bigfoot.com> - 2015-12-21 23:00 -0500
        Re: Does a capital ship sinking actually SUCK a swimmer down to drown? pnalsing@gmail.com - 2015-12-21 19:38 -0800
      Re: Does a capital ship sinking actually SUCK a swimmer down to drown? Poutnik <poutnik4nntp@gmail.com> - 2015-12-22 10:18 +0100
        Re: Does a capital ship sinking actually SUCK a swimmer down to drown? Micky <NONONOmisc07@bigfoot.com> - 2015-12-22 05:04 -0500
    Re: Does a capital ship sinking actually SUCK a swimmer down to drown? Sylvia Else <sylvia@not.at.this.address> - 2015-12-22 14:51 +1100
      Re: Does a capital ship sinking actually SUCK a swimmer down to drown? Tony Hwang <dragon40@shaw.ca> - 2015-12-21 21:06 -0700
        Re: Does a capital ship sinking actually SUCK a swimmer down to drown? Sylvia Else <sylvia@not.at.this.address> - 2015-12-22 16:13 +1100
          Re: Does a capital ship sinking actually SUCK a swimmer down to drown? Tony Hwang <dragon40@shaw.ca> - 2015-12-21 22:19 -0700
            Re: Does a capital ship sinking actually SUCK a swimmer down to drown? Sylvia Else <sylvia@not.at.this.address> - 2015-12-22 18:58 +1100
              Re: Does a capital ship sinking actually SUCK a swimmer down to drown? Poutnik <poutnik4nntp@gmail.com> - 2015-12-22 11:06 +0100
                Re: Does a capital ship sinking actually SUCK a swimmer down to drown? Sylvia Else <sylvia@not.at.this.address> - 2015-12-22 22:13 +1100
                  Re: Does a capital ship sinking actually SUCK a swimmer down to drown? Poutnik <poutnik4nntp@gmail.com> - 2015-12-22 12:45 +0100
                  Re: Does a capital ship sinking actually SUCK a swimmer down to drown? jimp@specsol.spam.sux.com - 2015-12-22 19:05 +0000
                    Re: Does a capital ship sinking actually SUCK a swimmer down to drown? "reber g=emc^2" <herbertglazier0@gmail.com> - 2015-12-22 13:19 -0800
      Re: Does a capital ship sinking actually SUCK a swimmer down to drown? "M. Stradbury" <mstradbury@example.com> - 2015-12-22 04:36 +0000
        Re: Does a capital ship sinking actually SUCK a swimmer down to drown? Poutnik <poutnik4nntp@gmail.com> - 2015-12-22 11:13 +0100
          Re: Does a capital ship sinking actually SUCK a swimmer down to drown? Micky <NONONOmisc07@bigfoot.com> - 2015-12-22 06:07 -0500
      Re: Does a capital ship sinking actually SUCK a swimmer down to drown? Poutnik <poutnik4nntp@gmail.com> - 2015-12-22 10:36 +0100
      Re: Does a capital ship sinking actually SUCK a swimmer down to drown? Poutnik <poutnik4nntp@gmail.com> - 2015-12-22 14:04 +0100
      Re: Does a capital ship sinking actually SUCK a swimmer down to drown? "taxed and spent" <pleasedonot@spamme.com> - 2015-12-22 05:08 -0800
    Re: Does a capital ship sinking actually SUCK a swimmer down to drown? O <OG@AIOESPAM.COM> - 2015-12-21 22:06 -0800
      Re: Does a capital ship sinking actually SUCK a swimmer down to drown? Poutnik <poutnik4nntp@gmail.com> - 2015-12-22 11:18 +0100
    Re: Does a capital ship sinking actually SUCK a swimmer down to drown? Poutnik <poutnik4nntp@gmail.com> - 2015-12-22 10:10 +0100
    Re: Does a capital ship sinking actually SUCK a swimmer down to drown? "(PeteCresswell)" <x@y.Invalid> - 2015-12-22 08:53 -0500
      Re: Does a capital ship sinking actually SUCK a swimmer down to drown? "M. Stradbury" <mstradbury@example.com> - 2015-12-22 14:28 +0000
        Re: Does a capital ship sinking actually SUCK a swimmer down to drown? "(PeteCresswell)" <x@y.Invalid> - 2015-12-22 11:41 -0500
          Re: Does a capital ship sinking actually SUCK a swimmer down to drown? "M. Stradbury" <mstradbury@example.com> - 2015-12-22 21:50 +0000
            Re: Does a capital ship sinking actually SUCK a swimmer down to drown? Poutnik <poutnik4nntp@gmail.com> - 2015-12-22 23:06 +0100
              Re: Does a capital ship sinking actually SUCK a swimmer down to drown? MJC <gravity@mjcoon.plus.com> - 2015-12-22 23:07 +0000
                Re: Does a capital ship sinking actually SUCK a swimmer down to drown? Poutnik <poutnik4nntp@gmail.com> - 2015-12-23 07:35 +0100
                  Re: Does a capital ship sinking actually SUCK a swimmer down to drown? "Robert Green" <robert_green1963@yah00.com> - 2015-12-23 13:31 -0500
                    Re: Does a capital ship sinking actually SUCK a swimmer down to drown? Poutnik <poutnik4nntp@gmail.com> - 2015-12-23 19:51 +0100
            Re: Does a capital ship sinking actually SUCK a swimmer down to drown? Tony Hwang <dragon40@shaw.ca> - 2015-12-22 16:25 -0700
              Re: Does a capital ship sinking actually SUCK a swimmer down to drown? Poutnik <poutnik4nntp@gmail.com> - 2015-12-23 07:43 +0100
    Re: Does a capital ship sinking actually SUCK a swimmer down to drown? Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2015-12-22 10:52 -0500
    Re: Does a capital ship sinking actually SUCK a swimmer down to drown? "Bob F" <bobnospam@gmail.com> - 2015-12-22 08:16 -0800

Page 1 of 3  [1] 2 3  Next page →

#540713 — Does a capital ship sinking actually SUCK a swimmer down to drown?

Is it true (or an urban myth) that a swimmer would be sucked
under (presumably to drown) when a capital ship sinks?

[toc] | [next] | [standalone]

#540726

M. Stradbury wrote:
> Is it true (or an urban myth) that a swimmer would be sucked
> under (presumably to drown) when a capital ship sinks?
>
Like toilet bowl water swirls.

[toc] | [prev] | [next] | [standalone]

#540729

On Mon, 21 Dec 2015 18:51:29 -0700, Tony Hwang <dragon40@shaw.ca>
wrote:

>M. Stradbury wrote:
>> Is it true (or an urban myth) that a swimmer would be sucked
>> under (presumably to drown) when a capital ship sinks?
>>
>Like toilet bowl water swirls.

I don't think the swirl is the part that matters.   If you pour a
half-bucket of water in a toilet, it will drain without swirling. It's
the draining and emptying that matters. 

[toc] | [prev] | [next] | [standalone]

#540749

On 12/21/2015 07:51 PM, Tony Hwang wrote:
> M. Stradbury wrote:
>> Is it true (or an urban myth) that a swimmer would be sucked
>> under (presumably to drown) when a capital ship sinks?
>>
> Like toilet bowl water swirls.

I think there was a TV show where a kid called a lot of people in places 
like Australia, to ask them which way the water swirls when they flush.

-- 
4 days until the winter celebration (Friday December 25, 2015 12:00:00
AM for 1 day).

"We could believe in God if he shortened the road for the lame, led the
blind or fed the starving." [Lemuel K. Washburn, _Is The Bible Worth
Reading And Other Essays_]

[toc] | [prev] | [next] | [standalone]

#540752

On Mon, 21 Dec 2015 18:51:29 -0700, Tony Hwang wrote:

> Like toilet bowl water swirls.

A toilet bowl is too small to show the Coriolis effect, but a pool isn't
according to Sandlin and Muller.

http://mashable.com/2015/06/04/water-toilet-swirl/#vRjaqfm0bSqs
  "Derek Muller and Destin Sandlin, the minds behind the Veritasium and 
   Smarter Every Day YouTube channels, respectively, do show that water 
   (and even hurricanes or cycloness) preferentially spins counter-clockwise 
   in the north and clockwise in the south, you just might not be able to 
   see it with your toilet water."

[toc] | [prev] | [next] | [standalone]

#540812

M. Stradbury wrote:
> On Mon, 21 Dec 2015 18:51:29 -0700, Tony Hwang wrote:
>
>> Like toilet bowl water swirls.
>
> A toilet bowl is too small to show the Coriolis effect, but a pool
> isn't according to Sandlin and Muller.
>
> http://mashable.com/2015/06/04/water-toilet-swirl/#vRjaqfm0bSqs
>  "Derek Muller and Destin Sandlin, the minds behind the Veritasium and
>   Smarter Every Day YouTube channels, respectively, do show that water
>   (and even hurricanes or cycloness) preferentially spins
>   counter-clockwise in the north and clockwise in the south, you just
>   might not be able to see it with your toilet water."

I just flushed both my toilets. One went clockwise. The other went 
counterclockwise. QED.

[toc] | [prev] | [next] | [standalone]

#540817

Dne 22/12/2015 v 17:19 Bob F napsal(a):
> M. Stradbury wrote:
>> On Mon, 21 Dec 2015 18:51:29 -0700, Tony Hwang wrote:
>>
>>> Like toilet bowl water swirls.
>>
>> A toilet bowl is too small to show the Coriolis effect, but a pool
>> isn't according to Sandlin and Muller.
>>
>> http://mashable.com/2015/06/04/water-toilet-swirl/#vRjaqfm0bSqs
>>  "Derek Muller and Destin Sandlin, the minds behind the Veritasium and
>>   Smarter Every Day YouTube channels, respectively, do show that water
>>   (and even hurricanes or cycloness) preferentially spins
>>   counter-clockwise in the north and clockwise in the south, you just
>>   might not be able to see it with your toilet water."
> 
> I just flushed both my toilets. One went clockwise. The other went 
> counterclockwise. QED.
> 
> 
There are too strong forces, fast current speeds
and random turbulent processes
for Coriolis force to have any effect.

-- 
Poutnik ( the Czech word for a wanderer )

Knowledge makes great men humble, but small men arrogant.

[toc] | [prev] | [next] | [standalone]

#540827

"Poutnik" <poutnik4nntp@gmail.com> wrote in message 
news:n5buih$4bn$1@dont-email.me...
> Dne 22/12/2015 v 17:19 Bob F napsal(a):
>> M. Stradbury wrote:
>>> On Mon, 21 Dec 2015 18:51:29 -0700, Tony Hwang wrote:
>>>
>>>> Like toilet bowl water swirls.
>>>
>>> A toilet bowl is too small to show the Coriolis effect, but a pool
>>> isn't according to Sandlin and Muller.
>>>
>>> http://mashable.com/2015/06/04/water-toilet-swirl/#vRjaqfm0bSqs
>>>  "Derek Muller and Destin Sandlin, the minds behind the Veritasium and
>>>   Smarter Every Day YouTube channels, respectively, do show that water
>>>   (and even hurricanes or cycloness) preferentially spins
>>>   counter-clockwise in the north and clockwise in the south, you just
>>>   might not be able to see it with your toilet water."
>>
>> I just flushed both my toilets. One went clockwise. The other went
>> counterclockwise. QED.
>>
>>
> There are too strong forces, fast current speeds
> and random turbulent processes
> for Coriolis force to have any effect.
>


When I was in Ecuador, I did my own test.  Quite a bit north of the equator, 
I filled a wash basin with water and pulled the plug.  The water swirled one 
way.

AT the equator, I did the same thing, and the water just drained.

A bit south of the equator, I did the same thing, and there wasn't much of 
interest.

Further south of the equator, I did the same thing, and the water swirled 
the opposite way.

I eliminated water current, toilet bowl rim jet patterns, etc.

Q.E.D. 

[toc] | [prev] | [next] | [standalone]

#540989

On Tue, 22 Dec 2015 08:19:12 -0800, "Bob F" <bobnospam@gmail.com>
wrote:

>M. Stradbury wrote:
>> On Mon, 21 Dec 2015 18:51:29 -0700, Tony Hwang wrote:
>>
>>> Like toilet bowl water swirls.
>>
>> A toilet bowl is too small to show the Coriolis effect, but a pool
>> isn't according to Sandlin and Muller.
>>
>> http://mashable.com/2015/06/04/water-toilet-swirl/#vRjaqfm0bSqs
>>  "Derek Muller and Destin Sandlin, the minds behind the Veritasium and
>>   Smarter Every Day YouTube channels, respectively, do show that water
>>   (and even hurricanes or cycloness) preferentially spins
>>   counter-clockwise in the north and clockwise in the south, you just
>>   might not be able to see it with your toilet water."
>
>I just flushed both my toilets. One went clockwise. The other went 
>counterclockwise. QED.

Not surprising.   Normally, quality home builders will put in a CW
toilet and a CCW toilet because if they were both the same direction
and both got flushed at once, it can damage the connection where the
house sits on the foundation.    If you buy a home already built, you
should make sure your toilets are opposite each other, or you should
be careful not to flush both at once. 

[toc] | [prev] | [next] | [standalone]

#540992

On 12/23/2015 3:08 AM, Micky wrote:
> On 22 Dec 2015 "Bob F" <bobnospam@gmail.com> wrote:
>> M. Stradbury wrote:
>>> On Mon, 21 Dec 2015 18:51:29 -0700, Tony Hwang wrote:
>>>
>>>> Like toilet bowl water swirls.
>>>
>>> A toilet bowl is too small to show the Coriolis effect, but a pool
>>> isn't according to Sandlin and Muller.
>>>
>>> http://mashable.com/2015/06/04/water-toilet-swirl/#vRjaqfm0bSqs
>>>   "Derek Muller and Destin Sandlin, the minds behind the Veritasium and
>>>    Smarter Every Day YouTube channels, respectively, do show that water
>>>    (and even hurricanes or cycloness) preferentially spins
>>>    counter-clockwise in the north and clockwise in the south, you just
>>>    might not be able to see it with your toilet water."
>>
>> I just flushed both my toilets. One went clockwise. The other went
>> counterclockwise. QED.
>
> Not surprising.   Normally, quality home builders will put in a CW
> toilet and a CCW toilet because if they were both the same direction
> and both got flushed at once, it can damage the connection where the
> house sits on the foundation.    If you buy a home already built, you
> should make sure your toilets are opposite each other, or you should
> be careful not to flush both at once.

I have never heard anything like that in all my years (50 of them) of 
construction, nor have I heard it from the plumbers to whom I have 
talked. If flushing a toilet can damage "connections" we better start 
building things a lot better.

-- 
dvus

[toc] | [prev] | [next] | [standalone]

#541002

Dne 23/12/2015 v 11:23 dvus napsal(a):
> On 12/23/2015 3:08 AM, Micky wrote:

>>
>> Not surprising.   Normally, quality home builders will put in a CW
>> toilet and a CCW toilet because if they were both the same direction
>> and both got flushed at once, it can damage the connection where the
>> house sits on the foundation.    If you buy a home already built, you
>> should make sure your toilets are opposite each other, or you should
>> be careful not to flush both at once.
> 
> I have never heard anything like that in all my years (50 of them) of 
> construction, nor have I heard it from the plumbers to whom I have 
> talked. If flushing a toilet can damage "connections" we better start 
> building things a lot better.
> 
It rather looks like you became a joke victim.
Due random turbulent effects, the result of the toilet splash
is random as well.

What may be the issue
is the design of plumbing wrt the capacity.

If all guests of multi floor hotel
got diarrhea after eating "salmonellized" dinner...

-- 
Poutnik ( the Czech word for a wanderer )

Knowledge makes great men humble, but small men arrogant.

[toc] | [prev] | [next] | [standalone]

#541023

Micky wrote:
> On Tue, 22 Dec 2015 08:19:12 -0800, "Bob F" <bobnospam@gmail.com>
> wrote:
>
>> M. Stradbury wrote:
>>> On Mon, 21 Dec 2015 18:51:29 -0700, Tony Hwang wrote:
>>>
>>>> Like toilet bowl water swirls.
>>>
>>> A toilet bowl is too small to show the Coriolis effect, but a pool
>>> isn't according to Sandlin and Muller.
>>>
>>> http://mashable.com/2015/06/04/water-toilet-swirl/#vRjaqfm0bSqs
>>>  "Derek Muller and Destin Sandlin, the minds behind the Veritasium
>>>   and Smarter Every Day YouTube channels, respectively, do show
>>>   that water (and even hurricanes or cycloness) preferentially spins
>>>   counter-clockwise in the north and clockwise in the south, you
>>>   just might not be able to see it with your toilet water."
>>
>> I just flushed both my toilets. One went clockwise. The other went
>> counterclockwise. QED.
>
> Not surprising.   Normally, quality home builders will put in a CW
> toilet and a CCW toilet because if they were both the same direction
> and both got flushed at once, it can damage the connection where the
> house sits on the foundation.    If you buy a home already built, you
> should make sure your toilets are opposite each other, or you should
> be careful not to flush both at once.

LOL!  Really.

[toc] | [prev] | [next] | [standalone]

#540727

On Tue, 22 Dec 2015 00:04:23 -0000 (UTC), "M. Stradbury"
<mstradbury@example.com> wrote:

>Is it true (or an urban myth) that a swimmer would be sucked
>under (presumably to drown) when a capital ship sinks?

I would think so.   I was in a 6-man rubber raft that went over a
small falls and under water and though I wasn't tied to the raft, I
went under water too.   How much more so with a big ship. 

Something about traveling and being on my own made me fearless however
and I confidently waited, with my eyes open iirc, until I popped up
again a few seconds later.   Without the raft. 

This was the Dranze River in France, just east of Geneva, Switzerland.

[toc] | [prev] | [next] | [standalone]

#540730

Micky wrote:
> On Tue, 22 Dec 2015 00:04:23 -0000 (UTC), "M. Stradbury"
> <mstradbury@example.com> wrote:
>
>> Is it true (or an urban myth) that a swimmer would be sucked
>> under (presumably to drown) when a capital ship sinks?
>
> I would think so.   I was in a 6-man rubber raft that went over a
> small falls and under water and though I wasn't tied to the raft, I
> went under water too.   How much more so with a big ship.
>
> Something about traveling and being on my own made me fearless however
> and I confidently waited, with my eyes open iirc, until I popped up
> again a few seconds later.   Without the raft.
>
> This was the Dranze River in France, just east of Geneva, Switzerland.
>
Basic fluid mechanics. You know that the swirl direction of opposite of
Southern hemisphere. CCW and CW. Rotating earth.

[toc] | [prev] | [next] | [standalone]

#540739

On Mon, 21 Dec 2015 19:02:56 -0700, Tony Hwang <dragon40@shaw.ca>
wrote:

>Micky wrote:
>> On Tue, 22 Dec 2015 00:04:23 -0000 (UTC), "M. Stradbury"
>> <mstradbury@example.com> wrote:
>>
>>> Is it true (or an urban myth) that a swimmer would be sucked
>>> under (presumably to drown) when a capital ship sinks?

In panic, someone might not hold his breath, and even more likely, he
might not take a big enough breath to be able to hold his breath for
long, but I would think if one does get a big breath and doesn't
panic, he should be able to hold it easily long enough to come to the
surface again.   

Does it depend on how fat he is how fast he surfaces?   Probably.  So
if you anticipate being on a sinking ship, try to gain weight first.
(When my brother was in Viet Nam during the war, my mother wanted him
to gain weight to tide him over if he was taken prisoner.  He didnt'
go on patrol and he wasn't a flier, so the odds were very slim he
would be taken prisoner, but other than that, I think she was right. )
>>
>> I would think so.   I was in a 6-man rubber raft that went over a
>> small falls and under water and though I wasn't tied to the raft, I
>> went under water too.   How much more so with a big ship.
>>
>> Something about traveling and being on my own made me fearless however
>> and I confidently waited, with my eyes open iirc, until I popped up
>> again a few seconds later.   Without the raft.
>>
>> This was the Dranze River in France, just east of Geneva, Switzerland.
>>
>Basic fluid mechanics. 
>
>You know that the swirl direction of opposite of
>Southern hemisphere. CCW and CW. Rotating earth.

So I've heard. 

Hmm.   This post is not in reply to my reply to you where I took issue
with the importance of swirling.   But I'll answer anyhow. 

I'm not doubting that water in toilets swirls, or that water in eddies
swirls.   I'm saying that swirling water has nothing to do with
sucking someone in behind a sinking ship.   

In fact the water probably isn't swirling.  The forces that make water
swirl, in a bathtub for example, are weak compared to the tremendous
amount of water that surrounds a large sinking ship.   If the ship
were not sinking, there would be no swirling, and I don't think
sinking an inch every minute is enough to permit or cause swirling.  

It's when the weight of the ship and the water it now contains is
greater than the weight of the water the whole ship displaces that
sinking quickly begins, and at that point there isn't time enough
before the ship has totally sunk for substantial swirling to begin.
Perhaps not any swirling at all.   Note that it takes quite some time
to have it begin even in a bathtub.

The stage of sinking slowly can take hours, but when sinking quickly
begins, it takes no more than a minute, maybe two. 

To beat this to death, I think the thousands of times people get to
watch water go down a sink drain overhwhelms their lack of experience
with sinking ships.   However one can drop or throw rocks in a lake or
a river pool, off a pier for example, and see that there is no
swirling. 

(One could even attach small balls that float to the rock, with some
weak "adhesive" that fails when wet, and time how long it takes the
balls to return the surface.     Varying the depth of the water, or
the release time of the "glue", one could measure three data points
and extrapolate to a ship and a person, and a person with a life vest.

(Or maybe one doesn't need the rock for all of these experiements.
While the water falling into the opening would slow down resurfacing,
that water has filled in the hole within a measurable number of
seconds, and the real question is, What is the acceleration of a human
of given weight and size due to buoyancy, and how long would it take
to stop downward travel and cause upward travel, and what would the
total time be?   All but the downward speed could be extrapolated just
from measurements made by releasing floating balls from an underwater
device.) 

[toc] | [prev] | [next] | [standalone]

#540744

Micky wrote:
> On Mon, 21 Dec 2015 19:02:56 -0700, Tony Hwang <dragon40@shaw.ca>
> wrote:
>
>> Micky wrote:
>>> On Tue, 22 Dec 2015 00:04:23 -0000 (UTC), "M. Stradbury"
>>> <mstradbury@example.com> wrote:
>>>
>>>> Is it true (or an urban myth) that a swimmer would be sucked
>>>> under (presumably to drown) when a capital ship sinks?
>
> In panic, someone might not hold his breath, and even more likely, he
> might not take a big enough breath to be able to hold his breath for
> long, but I would think if one does get a big breath and doesn't
> panic, he should be able to hold it easily long enough to come to the
> surface again.
>
> Does it depend on how fat he is how fast he surfaces?   Probably.  So
> if you anticipate being on a sinking ship, try to gain weight first.
> (When my brother was in Viet Nam during the war, my mother wanted him
> to gain weight to tide him over if he was taken prisoner.  He didnt'
> go on patrol and he wasn't a flier, so the odds were very slim he
> would be taken prisoner, but other than that, I think she was right. )
>>>
>>> I would think so.   I was in a 6-man rubber raft that went over a
>>> small falls and under water and though I wasn't tied to the raft, I
>>> went under water too.   How much more so with a big ship.
>>>
>>> Something about traveling and being on my own made me fearless however
>>> and I confidently waited, with my eyes open iirc, until I popped up
>>> again a few seconds later.   Without the raft.
>>>
>>> This was the Dranze River in France, just east of Geneva, Switzerland.
>>>
>> Basic fluid mechanics.
>>
>> You know that the swirl direction of opposite of
>> Southern hemisphere. CCW and CW. Rotating earth.
>
> So I've heard.
>
> Hmm.   This post is not in reply to my reply to you where I took issue
> with the importance of swirling.   But I'll answer anyhow.
>
> I'm not doubting that water in toilets swirls, or that water in eddies
> swirls.   I'm saying that swirling water has nothing to do with
> sucking someone in behind a sinking ship.
>
> In fact the water probably isn't swirling.  The forces that make water
> swirl, in a bathtub for example, are weak compared to the tremendous
> amount of water that surrounds a large sinking ship.   If the ship
> were not sinking, there would be no swirling, and I don't think
> sinking an inch every minute is enough to permit or cause swirling.
m
> It's when the weight of the ship and the water it now contains is
> greater than the weight of the water the whole ship displaces that
> sinking quickly begins, and at that point there isn't time enough
> before the ship has totally sunk for substantial swirling to begin.
> Perhaps not any swirling at all.   Note that it takes quite some time
> to have it begin even in a bathtub.
>
> The stage of sinking slowly can take hours, but when sinking quickly
> begins, it takes no more than a minute, maybe two.
>
> To beat this to death, I think the thousands of times people get to
> watch water go down a sink drain overhwhelms their lack of experience
> with sinking ships.   However one can drop or throw rocks in a lake or
> a river pool, off a pier for example, and see that there is no
> swirling.
>
> (One could even attach small balls that float to the rock, with some
> weak "adhesive" that fails when wet, and time how long it takes the
> balls to return the surface.     Varying the depth of the water, or
> the release time of the "glue", one could measure three data points
> and extrapolate to a ship and a person, and a person with a life vest.
>
> (Or maybe one doesn't need the rock for all of these experiements.
> While the water falling into the opening would slow down resurfacing,
> that water has filled in the hole within a measurable number of
> seconds, and the real question is, What is the acceleration of a human
> of given weight and size due to buoyancy, and how long would it take
> to stop downward travel and cause upward travel, and what would the
> total time be?   All but the downward speed could be extrapolated just
> from measurements made by releasing floating balls from an underwater
> device.)
>
Hey, couple months ago whale watching boat rolled and sank hit by a big 
wave West of Vancouver Island, few died and some survived. A couple 
survived is from Calgary here. They both said they got sucked under and
then surfaced. My 2nd uncle is life time Navy man, Captain(ret), ROKN.
He said same thing.

[toc] | [prev] | [next] | [standalone]

#540746

On Mon, 21 Dec 2015 20:47:56 -0700, Tony Hwang <dragon40@shaw.ca>
wrote:

>Micky wrote:
>> On Mon, 21 Dec 2015 19:02:56 -0700, Tony Hwang <dragon40@shaw.ca>
>> wrote:
>>
>>> Micky wrote:
>>>> On Tue, 22 Dec 2015 00:04:23 -0000 (UTC), "M. Stradbury"
>>>> <mstradbury@example.com> wrote:
>>>>
>>>>> Is it true (or an urban myth) that a swimmer would be sucked
>>>>> under (presumably to drown) when a capital ship sinks?
>>
>> In panic, someone might not hold his breath, and even more likely, he
>> might not take a big enough breath to be able to hold his breath for
>> long, but I would think if one does get a big breath and doesn't
>> panic, he should be able to hold it easily long enough to come to the
>> surface again.
>>
>> Does it depend on how fat he is how fast he surfaces?   Probably.  So
>> if you anticipate being on a sinking ship, try to gain weight first.
>> (When my brother was in Viet Nam during the war, my mother wanted him
>> to gain weight to tide him over if he was taken prisoner.  He didnt'
>> go on patrol and he wasn't a flier, so the odds were very slim he
>> would be taken prisoner, but other than that, I think she was right. )
>>>>
>>>> I would think so.   I was in a 6-man rubber raft that went over a
>>>> small falls and under water and though I wasn't tied to the raft, I
>>>> went under water too.   How much more so with a big ship.
>>>>
>>>> Something about traveling and being on my own made me fearless however
>>>> and I confidently waited, with my eyes open iirc, until I popped up
>>>> again a few seconds later.   Without the raft.
>>>>
>>>> This was the Dranze River in France, just east of Geneva, Switzerland.
>>>>
>>> Basic fluid mechanics.
>>>
>>> You know that the swirl direction of opposite of
>>> Southern hemisphere. CCW and CW. Rotating earth.
>>
>> So I've heard.
>>
>> Hmm.   This post is not in reply to my reply to you where I took issue
>> with the importance of swirling.   But I'll answer anyhow.
>>
>> I'm not doubting that water in toilets swirls, or that water in eddies
>> swirls.   I'm saying that swirling water has nothing to do with
>> sucking someone in behind a sinking ship.
>>
>> In fact the water probably isn't swirling.  The forces that make water
>> swirl, in a bathtub for example, are weak compared to the tremendous
>> amount of water that surrounds a large sinking ship.   If the ship
>> were not sinking, there would be no swirling, and I don't think
>> sinking an inch every minute is enough to permit or cause swirling.
>m
>> It's when the weight of the ship and the water it now contains is
>> greater than the weight of the water the whole ship displaces that
>> sinking quickly begins, and at that point there isn't time enough
>> before the ship has totally sunk for substantial swirling to begin.
>> Perhaps not any swirling at all.   Note that it takes quite some time
>> to have it begin even in a bathtub.
>>
>> The stage of sinking slowly can take hours, but when sinking quickly
>> begins, it takes no more than a minute, maybe two.
>>
>> To beat this to death, I think the thousands of times people get to
>> watch water go down a sink drain overhwhelms their lack of experience
>> with sinking ships.   However one can drop or throw rocks in a lake or
>> a river pool, off a pier for example, and see that there is no
>> swirling.
>>
>> (One could even attach small balls that float to the rock, with some
>> weak "adhesive" that fails when wet, and time how long it takes the
>> balls to return the surface.     Varying the depth of the water, or
>> the release time of the "glue", one could measure three data points
>> and extrapolate to a ship and a person, and a person with a life vest.
>>
>> (Or maybe one doesn't need the rock for all of these experiements.
>> While the water falling into the opening would slow down resurfacing,
>> that water has filled in the hole within a measurable number of
>> seconds, and the real question is, What is the acceleration of a human
>> of given weight and size due to buoyancy, and how long would it take
>> to stop downward travel and cause upward travel, and what would the
>> total time be?   All but the downward speed could be extrapolated just
>> from measurements made by releasing floating balls from an underwater
>> device.)
>>
>Hey, couple months ago whale watching boat rolled and sank hit by a big 
>wave West of Vancouver Island, few died and some survived. A couple 

I heard abou tthat. 

>survived is from Calgary here. They both said they got sucked under and
>then surfaced. My 2nd uncle is life time Navy man, Captain(ret), ROKN.
>He said same thing.

I didn't hear about that.  Good to know.   Should make OP happy to
know too. 

Just remember to pretend you're in the doctor's office, suck in a big
breath and hold it. 

[toc] | [prev] | [next] | [standalone]

#540741

On Monday, December 21, 2015 at 6:03:03 PM UTC-8, Tony Hwang wrote:

> Basic fluid mechanics. You know that the swirl direction of opposite of
> Southern hemisphere. CCW and CW. Rotating earth.

Total urban legend...

http://www.snopes.com/science/coriolis.asp

https://www.washingtonpost.com/news/speaking-of-science/wp/2015/06/03/videos-synced-up-across-the-globe-prove-once-and-for-all-which-way-water-swirls/

http://www.scientificamerican.com/article/fact-or-fiction-south-of-equator-tornadoes-spin-in-opposite-direction/

[toc] | [prev] | [next] | [standalone]

#540773

Dne 22/12/2015 v 02:56 Micky napsal(a):
> On Tue, 22 Dec 2015 00:04:23 -0000 (UTC), "M. Stradbury"
> <mstradbury@example.com> wrote:
> 
>> Is it true (or an urban myth) that a swimmer would be sucked
>> under (presumably to drown) when a capital ship sinks?
> 
> I would think so.   I was in a 6-man rubber raft that went over a
> small falls and under water and though I wasn't tied to the raft, I
> went under water too.   How much more so with a big ship. 

But it could be because of your motion dynamics,
as you inertially continue water under,
until your buoyancy gradually reverted your velocity.


-- 
Poutnik ( the Czech word for a wanderer )

Knowledge makes great men humble, but small men arrogant.

[toc] | [prev] | [next] | [standalone]

#540776

On Tue, 22 Dec 2015 10:18:34 +0100, Poutnik <poutnik4nntp@gmail.com>
wrote:

>Dne 22/12/2015 v 02:56 Micky napsal(a):
>> On Tue, 22 Dec 2015 00:04:23 -0000 (UTC), "M. Stradbury"
>> <mstradbury@example.com> wrote:
>> 
>>> Is it true (or an urban myth) that a swimmer would be sucked
>>> under (presumably to drown) when a capital ship sinks?
>> 
>> I would think so.   I was in a 6-man rubber raft that went over a
>> small falls and under water and though I wasn't tied to the raft, I
>> went under water too.   How much more so with a big ship. 
>
>But it could be because of your motion dynamics,
>as you inertially continue water under,
>until your buoyancy gradually reverted your velocity.

True.   I'm no longer convinced.  (Even though I doubt mythbusters on
general principles).  If one were right by the ship when it went
quickly down, one would fall into the hole it left, but the water it
pushed aside would be crashing back right after the ship passed also.
How deep the person would go is a question. 

I think if you were standing on the deck, whether the deck was
horizontal or leaning, you could drop as fast as the ship did.  Why
not?  Until there was enough water surrouding you for buoyancy to
matter. 

But if you were 3 inches from the ship, already floating in the water,
would you fall over like in a waterfall? I think so, but like I say,
you'd be competing with the water to see who and what dropped first. 

One could experiement with little floating balls and big rocks dropped
close to them, or better yet, held close to them at surface level and
then released.   A method for determining how deep they go would be
needed. 

Anyhow my point originally was no swirling.   I coudl have kept silent
on other stuff. 

[toc] | [prev] | [next] | [standalone]

Page 1 of 3  [1] 2 3  Next page →

Back to top | Article view | sci.physics

csiph-web