Wharro wins!
 

Do you know what exactly was wrong with the cylinders? Did
he know beforehand that they were not right?

Scotty


OzOne wrote in message
...
http://www.boatingoz.com.au/?Page=18260


Oz1...of the 3 twins.

I welcome you to crackerbox palace,We've been expecting
you.

Wharro wins!
 

"Scotty" scribbled thusly:
Do you know what exactly was wrong with the cylinders? Did
he know beforehand that they were not right?



OzOne wrote:
They weren't strong enough and broke.
I believe they thought they were to spec.


Are they 100% positive the rams weren't up to spec? Is it
also possible that the spec was undershooting for the loads?

But as for the supplier not giving you the right stuff, I'm
sad to say it happens all the time. In most cases it's
because they've been gypped themselves, not because they're
trying to con anyone.

The only way to be sure is to establish your own test lab,
buy 10 of them, test 9 to destruction and draw up a graph,
then install the 10th one with full knowledge of what it
will take.

That's really really expensive. Not even the America's Cup
guys do it that way. Shucks, even the U.S. Gov't (the worlds
heavyweight champion money spenders) doesn't, except in very
special cases.

DSK

Wharro wins!
 

DSK wrote:
"Scotty" scribbled thusly:
Do you know what exactly was wrong with the cylinders? Did
he know beforehand that they were not right?



OzOne wrote:
They weren't strong enough and broke.
I believe they thought they were to spec.


Are they 100% positive the rams weren't up to spec? Is it
also possible that the spec was undershooting for the loads?

But as for the supplier not giving you the right stuff, I'm
sad to say it happens all the time. In most cases it's
because they've been gypped themselves, not because they're
trying to con anyone.

The only way to be sure is to establish your own test lab,
buy 10 of them, test 9 to destruction and draw up a graph,
then install the 10th one with full knowledge of what it
will take.

That's what we do with mission critical stuff. In fact we built our own
test bed to test to destruction wire swages and the like.

That's really really expensive. Not even the America's Cup
guys do it that way. Shucks, even the U.S. Gov't (the worlds
heavyweight champion money spenders) doesn't, except in very
special cases.

Yeah. I'd be interested in knowing just what spec the yacht designer
gave the hydraulics people so they could decide on the ram strength,
and how they knew that the load wasn't exceeded (ie, the failure was
due to inadequate spec rather than inadequate equipment). Personally I
wouldn't trust *anything* done by a racing yacht designer - look at the
failures, they obviously aren't using commercial standards for safe
working margins. Gear I use, the SWL is AT MOST 4X the actual failure
load, often 8X the actual failure load. And by actual failure load, I
mean one that's been determined by testing to destruction a
representative sample.

I suspect this is a case of deep pockets.....

PDW

Wharro wins!
 

The only way to be sure is to establish your own test lab,
buy 10 of them, test 9 to destruction and draw up a graph,
then install the 10th one with full knowledge of what it
will take.


Peter wrote:
That's what we do with mission critical stuff. In fact we built our own
test bed to test to destruction wire swages and the like.


A straight tension pull-tester isn't too difficult to
construct. Can you put on impulse loads and calibrate the
application of each successive load precisely?

It would be really difficult to test actuating gear the size
& strength of Skandia's keel canting mechanism. The best &
simplest way to do it would be to take the biggest tower
shaker... a gizmo cobbled up in the 1970s to test
installations at nuke power plants & simulate earthquake
conditions... pick up the boat by the keel with it, and give
it a hell of a shaking. I'm not sure that would be enough
and I'm not sure there are any around (Tadpole would likely
know).

The benefit is that that would also test the keel, the
trunnions, the hull panels.... the whole assembly.



Yeah. I'd be interested in knowing just what spec the yacht designer
gave the hydraulics people so they could decide on the ram strength,
and how they knew that the load wasn't exceeded (ie, the failure was
due to inadequate spec rather than inadequate equipment). Personally I
wouldn't trust *anything* done by a racing yacht designer - look at the
failures, they obviously aren't using commercial standards for safe
working margins.

Of course not, if they were, they'd lose ;)

OTOH contrary to popular opinion, racing yachts are built
very strongly. The failures tend to get a lot of publicity
and of course they always come at a bad time. It's also the
nature of the beast that very few are soft, gradual
failures. The breakage of Skandia's keel was about as benign
as could be.


I suspect this is a case of deep pockets.....


Has Australia learned so much from the American tort system
so fast??

Fresh Breezes- Doug King

Wharro wins!
 

OzOne wrote in message
...
On Tue, 08 Aug 2006 09:35:45 -0400, DSK

scribbled thusly:

"Scotty" scribbled thusly:
Do you know what exactly was wrong with the cylinders?
Did
he know beforehand that they were not right?



OzOne wrote:
They weren't strong enough and broke.
I believe they thought they were to spec.


Are they 100% positive the rams weren't up to spec? Is it
also possible that the spec was undershooting for the
loads?

But as for the supplier not giving you the right stuff,
I'm
sad to say it happens all the time. In most cases it's
because they've been gypped themselves, not because
they're
trying to con anyone.

The only way to be sure is to establish your own test
lab,
buy 10 of them, test 9 to destruction and draw up a
graph,
then install the 10th one with full knowledge of what it
will take.

That's really really expensive. Not even the America's
Cup
guys do it that way. Shucks, even the U.S. Gov't (the
worlds
heavyweight champion money spenders) doesn't, except in
very
special cases.

DSK

They were under spec.


in what way?

Wharro wins!
 

DSK wrote:
The only way to be sure is to establish your own test lab,
buy 10 of them, test 9 to destruction and draw up a graph,
then install the 10th one with full knowledge of what it
will take.


Peter wrote:
That's what we do with mission critical stuff. In fact we built our own
test bed to test to destruction wire swages and the like.


A straight tension pull-tester isn't too difficult to
construct. Can you put on impulse loads and calibrate the
application of each successive load precisely?

Nope, don't need to for our applications.


It would be really difficult to test actuating gear the size
& strength of Skandia's keel canting mechanism. The best &
simplest way to do it would be to take the biggest tower
shaker... a gizmo cobbled up in the 1970s to test
installations at nuke power plants & simulate earthquake
conditions... pick up the boat by the keel with it, and give
it a hell of a shaking. I'm not sure that would be enough
and I'm not sure there are any around (Tadpole would likely
know).

The benefit is that that would also test the keel, the
trunnions, the hull panels.... the whole assembly.

And when you find the failure point - you build a new hull :-)

Yeah. I'd be interested in knowing just what spec the yacht designer
gave the hydraulics people so they could decide on the ram strength,
and how they knew that the load wasn't exceeded (ie, the failure was
due to inadequate spec rather than inadequate equipment). Personally I
wouldn't trust *anything* done by a racing yacht designer - look at the
failures, they obviously aren't using commercial standards for safe
working margins.

Of course not, if they were, they'd lose ;)

OTOH contrary to popular opinion, racing yachts are built
very strongly.

Don't doubt that at all - depending on your definition of 'strongly'.
It comes back to the designer's margins for the material used. As I
said, most of what I use is designed to a load 1/4 to 1/8 of the tested
breaking load. If I planned on loading something up to 90% of its
breaking strain, and it broke, I wouldn't consider it 'strong' and I
wouldn't be blaming the materials.

One quite expensive bit of gear I use puts heave strains on a cable
that are 2/3 of its tested breaking strain. We have heave compensation,
tension controls etc to minimise the risks. Even so, we've lost 2 over
the years. Due to the depths and other operating constraints, we can't
really do anything about it. Losing gear in this case is the cost of
doing business. WRT racing boats, breaking stuff - ditto.

WRT Skandia, if a piece of supplied equipment from a 3rd party failed
at less than its specified load, it was faulty. If it was overloaded to
failure point, the design was inadequate. The article Oz quoted doesn't
have any details.

The failures tend to get a lot of publicity
and of course they always come at a bad time. It's also the
nature of the beast that very few are soft, gradual
failures. The breakage of Skandia's keel was about as benign
as could be.

Note there was no backup plan, or if there was, it hadn't been tested &
known to work.

I suspect this is a case of deep pockets.....


Has Australia learned so much from the American tort system
so fast??

Unfortunately - yes.

PDW

Wharro wins!
 

I thought Pete meant the ram co. had deep pockets?



That's because you're an idiot.



RB
35s5
NY

Wharro wins!
 

OzOne wrote in message
...
On Wed, 9 Aug 2006 08:51:30 -0400, "Scotty"

scribbled thusly:



They were under spec.


in what way?



From the article.
The supplier of the hydraulic cylinders that controlled
the canting
keel on Skandia in the 2004 Rolex Sydney Hobart Race was
found to have
breached their contract and supplied inadequate hydraulic
cylinders
for the duty specified by the yacht’s designer.
IOW, the yacht designer did not have the necessary
knowledge to design
the rams.
He instead gave a duty spec to the experts (the ram
suppliers and
their engineers) who supplied rams that did not meet the
duty spec.


OK, the rams failed,but I still don't know what broke.


Oh and it's not about deep pockets.
Skandia was built using Wharro's own money, he sold his
house to
complete the yacht which was uninsured.

I thought Pete meant the ram co. had deep pockets?

Scotty

Wharro wins!
 

OzOne wrote:
From the article.
The supplier of the hydraulic cylinders that controlled the canting
keel on Skandia in the 2004 Rolex Sydney Hobart Race was found to have
breached their contract and supplied inadequate hydraulic cylinders
for the duty specified by the yacht’s designer.
IOW, the yacht designer did not have the necessary knowledge to design
the rams.
He instead gave a duty spec to the experts (the ram suppliers and
their engineers) who supplied rams that did not meet the duty spec.


Well, I'm not trying to be a jerk, but how did they know
that the spec was not exceeded by the stresses on the boat
in the storm?

The only way to be sure the rams were strong enough is if
the boat's hull broke around them.

This is a matter of professional interest for me.


Oh and it's not about deep pockets.
Skandia was built using Wharro's own money, he sold his house to
complete the yacht which was uninsured.


Right, I read the same... now *that's* devotion. I hope he
manages to get the yacht sailing again.

The 'deep pockets' phrase refers to lawyers (at least here
in America) going after the richest target to sue; not
necessarily the most culpable party if they have fewer
assets to plunder. For example, don't sue the MacDonald's
counter help for serving coffee so hot that it causes severe
burns if you're clumsy enough to spill it on yourself... no
no, sue the MacDonald's chain corporation. It happens in
medical suits, also.

Fresh Breezes- Doug King

Wharro wins!
 

DSK wrote:
OzOne wrote:
From the article.
The supplier of the hydraulic cylinders that controlled the canting
keel on Skandia in the 2004 Rolex Sydney Hobart Race was found to have
breached their contract and supplied inadequate hydraulic cylinders
for the duty specified by the yacht's designer.
IOW, the yacht designer did not have the necessary knowledge to design
the rams.
He instead gave a duty spec to the experts (the ram suppliers and
their engineers) who supplied rams that did not meet the duty spec.


Well, I'm not trying to be a jerk, but how did they know
that the spec was not exceeded by the stresses on the boat
in the storm?

Bingo. That's exactly my concern as well. Seems to be a case of 'oh,
the rams broke. Must have been defective/inadequate'. Now that might be
true, but it also might not.

If I was given a spec to build an instrumented sheave capable of
handling a SWL of 2 tonnes and somehow the cable hooked up on
something, had a breaking strain of 10 tonnes, and the block shattered
under the excess load, it's not the fault of the design *or* the
construction. The load is outside the spec.

How do Wharro et al know that the applied load at failure was within
design spec? If the yacht designer, naval architect etc didn't provide
a spec with numbers then IMO the hydraulics guy was foolish in
accepting the job. Hindsight is a wonderful thing of course.


The only way to be sure the rams were strong enough is if
the boat's hull broke around them.

Which is exactly what'll happen next time, I predict. Alternatively, no
ram supplier will touch the job unless the designer specs the rams &
hydraulics in detail.


This is a matter of professional interest for me.

Me, too. This reinforces my resolve to *never* do private jobs for
people, too.



Oh and it's not about deep pockets.
Skandia was built using Wharro's own money, he sold his house to
complete the yacht which was uninsured.

Yes, I understand that. But from an engineering POV it's irrelevant. I
regard racing as an inherently high risk activity. Nobody designs for
the worst case strains etc because if they did, they'd never win a
race. It's hardly surprising if something breaks in a storm.

PDW