Prev: about dead-band used in pwm
Next: Confusing Spectrogram of a chirp signal
From: Jerry Avins on 7 May 2010 11:17
On 5/7/2010 10:34 AM, Clay wrote:
> On May 6, 11:21 pm, Jerry Avins<j...(a)ieee.org> wrote:
>> On 5/6/2010 3:08 PM, HardySpicer wrote:
>>
>> ...
>>
>>> Go and do an Elec End Major and find out...
>>> Amateurs...
>>
>> Noah was an amateur. The Titanic and the Andrea Doria were built by
>> professionals.
>>
>
> Well with the Titanic and the Andrea Doria, the main problem seems to
> be not how they were built but how they were captained. They each ran
> into a large object. You know that more scuba divers have died on the
> wreck of the Andrea Doria than passengers died on the ship when it
> sank? I've been on some deep wrecks but not that deep - it is too
> dangerous.

The Titanic was built with steel -- particularly rivets -- that didn't
meet spec. The force of the collision popped all the rivets in one
strake, opening the side of the ship like (if you remember them) a
key-opened coffee can.

The Andrea Doria was designed for the luxury trade. To spare the
upper-deck passengers the need to duck through those oval doorways, the
bulkheads ended one deck below the weather deck. Design calculations
showed (correctly) that flooding any one compartment wouldn't impair the
ships maneuverability, and that it would stay afloat even with two
flooded compartments on each side. That's where bad captaining came in.

The Stockholm hit the Andria Doria right on a bulkhead, opening two
compartments to the sea. The Stockholm's prow penetrated the Andrea
Doria's hull above the waterline. (An Andrea Doria passenger was later
found unhurt in the Stockholm' chain room.) The crumpled bulkhead caused
the leaks. The crew delayed (or neglected) flooding a compartment on the
other side to minimize list. When she listed far enough to put the top
of the short bulkheads under water, flooding spread from compartment to
compartment and she eventually capsized.

The Stockholm returned to port under her own power, carrying many of the
Andrea Doria survivors. Actually, the Andrea Doria went down because I
had put a hex on it the day before. Story on request.

Jerry
--
"I view the progress of science as ... the slow erosion of the tendency
to dichotomize." --Barbara Smuts, U. Mich.
�����������������������������������������������������������������������
From: glen herrmannsfeldt on 7 May 2010 14:54
Jerry Avins <jya(a)ieee.org> wrote:
(snip)

> The Titanic was built with steel -- particularly rivets -- that didn't
> meet spec. The force of the collision popped all the rivets in one
> strake, opening the side of the ship like (if you remember them) a
> key-opened coffee can.

According to a book I had not so long ago, they used both steel
and wrought iron. Steel was new, and there were many required
tests to assure that it met spec., and the spec. was strict.

Wrought iron was well understood, and it was believe that it
didn't need to be tested so carefully. Before this book, I
didn't really know about wrought iron. (And they didn't really
understand it back then, either.) As I understand it, the
wrought iron process separates the iron from the impurities.
When done right, the impurities form fibers that strengthen
the result in a specific direction. That is, the resulting
material is anisotropic. In a rivet, you want the strong
direction to be along the rivet axis, which would happen if
done according to the well known process. It seems, though,
that construction was rushed. (To meet schedule, maybe even
already selling tickets for a specific date.)

The claim, then, is that it was the poor quality wrought iron
rivets that caused the problem. There was even a test done
on one brought up from the wreck, showing that the grain was
in the wrong direction, and it failed way to easily.

Also, it seesm not to be the previously thought problem with
a low temperature brittle phase of steel. (I think steel,
not iron.) It seems that the Titanic was built with both
steel and iron, for both rivets and plates, during the transition
from one to the other.

-- glen
From: Jerry Avins on 7 May 2010 15:22
On 5/7/2010 2:54 PM, glen herrmannsfeldt wrote:
> Jerry Avins<jya(a)ieee.org> wrote:
> (snip)
>
>> The Titanic was built with steel -- particularly rivets -- that didn't
>> meet spec. The force of the collision popped all the rivets in one
>> strake, opening the side of the ship like (if you remember them) a
>> key-opened coffee can.
>
> According to a book I had not so long ago, they used both steel
> and wrought iron. Steel was new, and there were many required
> tests to assure that it met spec., and the spec. was strict.
>
> Wrought iron was well understood, and it was believe that it
> didn't need to be tested so carefully. Before this book, I
> didn't really know about wrought iron. (And they didn't really
> understand it back then, either.) As I understand it, the
> wrought iron process separates the iron from the impurities.
> When done right, the impurities form fibers that strengthen
> the result in a specific direction. That is, the resulting
> material is anisotropic. In a rivet, you want the strong
> direction to be along the rivet axis, which would happen if
> done according to the well known process. It seems, though,
> that construction was rushed. (To meet schedule, maybe even
> already selling tickets for a specific date.)
>
> The claim, then, is that it was the poor quality wrought iron
> rivets that caused the problem. There was even a test done
> on one brought up from the wreck, showing that the grain was
> in the wrong direction, and it failed way to easily.
>
> Also, it seesm not to be the previously thought problem with
> a low temperature brittle phase of steel. (I think steel,
> not iron.) It seems that the Titanic was built with both
> steel and iron, for both rivets and plates, during the transition
> from one to the other.

Thank you. I knew that the failed rivets were wrought iron, but
oversimplified. You did a good thing to set the record straight.

Jerry
--
"I view the progress of science as ... the slow erosion of the tendency
to dichotomize." --Barbara Smuts, U. Mich.
�����������������������������������������������������������������������
From: glen herrmannsfeldt on 7 May 2010 18:42
Jerry Avins <jya(a)ieee.org> wrote:
(snip on Titanic rivets, steel, and wrought iron)

> Thank you. I knew that the failed rivets were wrought iron, but
> oversimplified. You did a good thing to set the record straight.

I think it was:

"What really sank the Titanic : new forensic discoveries /
Jennifer Hooper McCarty and Tim Foecke"

-- glen
From: Phil Martel on 8 May 2010 12:47

"Jerry Avins" <jya(a)ieee.org> wrote in message
news:vaWEn.176$gv4.169(a)newsfe09.iad...
> On 5/7/2010 10:34 AM, Clay wrote:
>> On May 6, 11:21 pm, Jerry Avins<j...(a)ieee.org> wrote:
>>> On 5/6/2010 3:08 PM, HardySpicer wrote:
>>>
>>> ...
>>>
>>>> Go and do an Elec End Major and find out...
>>>> Amateurs...
>>>
>>> Noah was an amateur. The Titanic and the Andrea Doria were built by
>>> professionals.
>>>
>>
>> Well with the Titanic and the Andrea Doria, the main problem seems to
>> be not how they were built but how they were captained. They each ran
>> into a large object. You know that more scuba divers have died on the
>> wreck of the Andrea Doria than passengers died on the ship when it
>> sank? I've been on some deep wrecks but not that deep - it is too
>> dangerous.
>
> The Titanic was built with steel -- particularly rivets -- that didn't
> meet spec. The force of the collision popped all the rivets in one strake,
> opening the side of the ship like (if you remember them) a key-opened
> coffee can.
>
> The Andrea Doria was designed for the luxury trade. To spare the
> upper-deck passengers the need to duck through those oval doorways, the
> bulkheads ended one deck below the weather deck. Design calculations
> showed (correctly) that flooding any one compartment wouldn't impair the
> ships maneuverability, and that it would stay afloat even with two flooded
> compartments on each side. That's where bad captaining came in.
>
> The Stockholm hit the Andria Doria right on a bulkhead, opening two
> compartments to the sea. The Stockholm's prow penetrated the Andrea
> Doria's hull above the waterline. (An Andrea Doria passenger was later
> found unhurt in the Stockholm' chain room.) The crumpled bulkhead caused
> the leaks. The crew delayed (or neglected) flooding a compartment on the
> other side to minimize list. When she listed far enough to put the top of
> the short bulkheads under water, flooding spread from compartment to
> compartment and she eventually capsized.
>
> The Stockholm returned to port under her own power, carrying many of the
> Andrea Doria survivors. Actually, the Andrea Doria went down because I had
> put a hex on it the day before. Story on request.
>
> Jerry
> --
> "I view the progress of science as ... the slow erosion of the tendency
> to dichotomize." --Barbara Smuts, U. Mich.
> ��

Ok Jerry,

I'm curious. If you dn't want to post the sory to comp.dsp, please e-mail
it to me.

Best wishes,
--Phil Martel


First  |  Prev  |  Next  |  Last
Pages: 1 2 3 4
Prev: about dead-band used in pwm
Next: Confusing Spectrogram of a chirp signal