OT - it is about crabs

The picture is bad but it's still interestiing. The poor crab just
disappears.

http://www.digitalfog.com/gallery/crab.htm

B J Conner wrote:
The picture is bad but it's still interestiing. The poor crab just
disappears.

http://www.digitalfog.com/gallery/crab.htm



crab juice

--
Cut "to the chase" for my email address.

Always wondered how you make a crab cocktail.
--
Frank Reid
Reverse email to reply

I wonder:
a) what the guy at the other end of the pipe thought that greygreen
chunky sludge was that come through the pipe
b) what that pipe carried
c) how it kept from collapsing when the structural integrity was
compromised by the saw. Thats a lot of PSI, as the crab will attest.

--riverman

"riverman" wrote in message
oups.com...
I wonder:
a) what the guy at the other end of the pipe thought that greygreen
chunky sludge was that come through the pipe
b) what that pipe carried
c) how it kept from collapsing when the structural integrity was
compromised by the saw. Thats a lot of PSI, as the crab will attest.

--riverman


huh?

Umm, lots of outside pressure on something like a cylinder compresses
it evenly, like squeezing an egg in your hand without it breaking. But
if you compromise ths struture of the the tube, it can implode. Just
wondering how the tube keeps from imploding when they cut into it.

Did I miss something?

Again?

--riverman

"riverman" wrote in message
oups.com...
Umm, lots of outside pressure on something like a cylinder compresses
it evenly, like squeezing an egg in your hand without it breaking. But
if you compromise ths struture of the the tube, it can implode. Just
wondering how the tube keeps from imploding when they cut into it.

Did I miss something?

Again?

The list of suitable materials for a pipeline at that kind of depth and
pressure is going to be a very short one. It's safe to assume, I think,
that it's some sort of steel. Can't tell much for sure about the size of
the pipe but assuming the crab is neither a giant nor a pygmy species, and
judging by the hint of curvature in the cut, I'd guess we're looking at
something in the range of several inches to a couple of feet in diameter.
Even at ground level and low pressures pipe that size would have a wall
thickness of 1/4 inch or more. I haven't looked it up, but I'm pretty sure
that 2700 psi is well within the strength limits of just about any steel at
that thickness.

What I find curious is the assertion that pressure inside the pipe is 0
psi. Why (and how, for that matter) would someone generate and maintain a
vacuum in a pipeline at that depth and pressure? Then too, if you pause the
video at just the right point, it looks very much like about half of the
crab gets across the cut with no apparent difficulty before the whole thing
gets sucked in. And then it disappears in large chunks. If the suction is
great enough to make big chunks of crab disappear in a small fraction of a
second, how did it manage to get so far? Shouldn't it have gone in feet
first?

Wolfgang

"Wolfgang" wrote in message
...

"riverman" wrote in message
oups.com...
Umm, lots of outside pressure on something like a cylinder compresses
it evenly, like squeezing an egg in your hand without it breaking. But
if you compromise ths struture of the the tube, it can implode. Just
wondering how the tube keeps from imploding when they cut into it.

Did I miss something?

Again?

The list of suitable materials for a pipeline at that kind of depth and
pressure is going to be a very short one. It's safe to assume, I think,
that it's some sort of steel. Can't tell much for sure about the size of
the pipe but assuming the crab is neither a giant nor a pygmy species, and
judging by the hint of curvature in the cut, I'd guess we're looking at
something in the range of several inches to a couple of feet in diameter.
Even at ground level and low pressures pipe that size would have a wall
thickness of 1/4 inch or more. I haven't looked it up, but I'm pretty
sure
that 2700 psi is well within the strength limits of just about any steel
at
that thickness.

What I find curious is the assertion that pressure inside the pipe is 0
psi. Why (and how, for that matter) would someone generate and maintain a
vacuum in a pipeline at that depth and pressure? Then too, if you pause
the
video at just the right point, it looks very much like about half of the
crab gets across the cut with no apparent difficulty before the whole
thing
gets sucked in. And then it disappears in large chunks. If the suction
is
great enough to make big chunks of crab disappear in a small fraction of a
second, how did it manage to get so far? Shouldn't it have gone in feet
first?

Wolfgang


That has to be a natural gas pipeline. The North Sea has some that may be
that deep. The deepest one I remember reading about is the one from North
Africa to Italy. The crab has to have stumbled onto the cut soon after the
operation began. The pipe was probably depressurized for the cut and may
have been purged with nitrogen. Once the cut is opened up the inflow would
only last till the pipe filled up.
Pipeline engineering is at pretty advanced state, crab collapse mechanics
is an untouched science.

Actually, if you look closely (or compare the end and start images),
the entire crab doesn't even get sucked in. A big piece get stuck right
against the saw blade, near where it looks like the saw did a double
cut. My guess is that the whirling saw blade did as much to segment the
crab (or at least break its shell initially) as the 'pressure'.

--riverman

Wouldn't there be bubbles of nitrogen escaping as the water flooded the
pipe?

--riverman