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Grande Mastere Dreade

Showtime capsize on return trip

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WS have been looking into in build validation for several years, but the level of bureaucracy and costs for an industry where margins are already tight isn’t adding up. Steps are gradually being taken though 

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5 hours ago, Boink said:

Ncik, how on earth are they going to investigate meaningfully, when the two critically important parts, remain missing?

Good intentions or not, this is a highly flawed approach.

Boink,

 

It’s a pity it’s a Olympic year, other wise AS would of started a search and rescue for the boat to bring it back no matter what the cost. This way they could make their investigation meaningful. I understand that the Tasmanian Department of AS are still on standby if the president give the orders. 

 

Well, at least they have the Olympic gravetrain for the management to attend this year and the name change to consider to help improve their corporate image.

 

Pulpit

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5 hours ago, Fiji Bitter said:

Show me the drawings, and we possibly don't need any more evidence. 

 

Fiji,

 

What is  having the drawings going to do other than say the well respected naval architect designed a Keel to a standard. It’s only 1 part of the picture. Without the Boat or the Keel the drawings are meaningless and any report will just be speciation and will lead to legal action by 1 of the concerned parties if AS are not careful 

 

Pulpit

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Found the other ISO weld.......

The Excalibur was built at the Applied Alloy Yachts factory in Bayswater, Melbourne, where Cittadini was both a co-director and supervising engineer.

Alex Cittadini, the director and engineer of Applied Alloy Yachts, the now-defunct company that built the yacht, was found guilty on four counts of manslaughter in the NSW District Court.
The jury found Cittadini either knew about the cut and reweld, or should have.
Adrian Presland, the man who built the keel under Cittadini's supervision, was acquitted of manslaughter charges earlier this week.

EDIT appealed and charges dropped, looks like pranksters broke into the workshop, cut the keel and welded it back together...

 

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Just now, pulpit said:

Fiji,

 

What is  having the drawings going to do other than say the well respected naval architect designed a Keel to a standard. It’s only 1 part of the picture. Without the Boat or the Keel the drawings are meaningless and any report will just be speciation and will lead to legal action by 1 of the concerned parties if AS are not careful 

 

Pulpit

Pulpit,

The drawings will not tell the whole story, of course, but they may tell something.

Like, was it indeed designed to the required standard, and was it approved according to the rules.

And even if it was all 100% correctly approved, several of the pundits here may be critical of the construction anyway. I myself know a little bit about the Drum keel, and this case may be similar.

And legal action? It sounds like AS is not so worried about it, and neither am I... ;)

Many of you Aussie's seem so oversensitive about AS, that it is blurring your vision. I don't follow the AS thread, and neither all the Queensland shit, but from this tread alone it is obvious that there is a deep mistrust. I do remember something crooked with the Olympic selection, much like that infamous case in the US, I believe. And yes, that and a lot of other stuff would make me mad too.

But many here just want to find out as much as possible why the keel failed. There have been far to many keel accidents, and far to many bad ones I am afraid, and one bad one  affected me personally. And I personally know and talked to several of the lucky survivors, of three boats with clean breaks, and one was still shaking a couple of days after the dramatic rescue. This subject is important to me.

 

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25 minutes ago, Fiji Bitter said:

Pulpit,

The drawings will not tell the whole story, of course, but they may tell something.

Like, was it indeed designed to the required standard, and was it approved according to the rules.

And even if it was all 100% correctly approved, several of the pundits here may be critical of the construction anyway. I myself know a little bit about the Drum keel, and this case may be similar.

And legal action? It sounds like AS is not so worried about it, and neither am I... ;)

Many of you Aussie's seem so oversensitive about AS, that it is blurring your vision. I don't follow the AS thread, and neither all the Queensland shit, but from this tread alone it is obvious that there is a deep mistrust. I do remember something crooked with the Olympic selection, much like that infamous case in the US, I believe. And yes, that and a lot of other stuff would make me mad too.

But many here just want to find out as much as possible why the keel failed. There have been far to many keel accidents, and far to many bad ones I am afraid, and one bad one  affected me personally. And I personally know and talked to several of the lucky survivors, of three boats with clean breaks, and one was still shaking a couple of days after the dramatic rescue. This subject is important to me.

 

the engineering is guesstimation  not tested to failure to create a standard, canting keels proved that

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53 minutes ago, Sailabout said:

EDIT appealed and charges dropped, looks like pranksters broke into the workshop, cut the keel and welded it back together...

And that happened how long ago, again?

https://www.smh.com.au/national/yacht-disaster-a-tragedy-waiting-to-happen-20050326-gdl073.html

(From page 1, by fastyacht)

 

Just now, Sailabout said:

the engineering is guesstimation  not tested to failure to create a standard, canting keels proved that

Not sure what you are on about, but plenty were tested to failure, and some of those reported on very extensively.

 

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The Showtime incident is surely not due to lack of maintenance as it was a new keel, ie 12 months old?

Not apparent without understanding the design point and the construction. There are lots of programs with keel fins that require regular maintenance and inspection after every event.

the engineering is guesstimation  not tested to failure to create a standard, canting keels proved that

This is total bullshit. The engineering is the engineering. It is based on an assumptions package and a design package. Done correctly, it delivers a solution within those assumptions for that design that works. Period. There is no guesstimation; it is applied math. To claim this is to demonstrate your complete ignorance of not only engineering, but science itself.

Engineering a keel fin and its attachment is no different to any of 1000s of other engineering applications from bridges to buildings to sewers to space ships. None of these are ever tested to failure. Yes, there are occasional engineering mistakes. Far more often, on analysis of failures, the assumptions are proven to be short sighted. But the biggest source of failure is not recalling the design package - for example, launching a space shuttle in sub-freezing weather.

And yet, one must have a design package and an assumption set. Your house has a roof with a design life and an assumption about live load due to snow. These are based on cost and climate and accepted standards of risk. One cannot engineer a roof with an infinite design life or an infinite load bearing ability. That someone chose a 25 year life and a 500 kg/m2 live load limit does not make the engineering behind that roof wrong should it begin to leak.

More to the point, why do you think there's even a problem with keel design? As near as I can tell, 6259 yachts have started the Sydney Hobart. So between races and deliveries, there have been 12518 passages. I can't find any clear answers for keel failures, but let's say 5, which is 0.04% failure rate. That's pretty small for a race that many claim is the "holy grail" (you just can't make this shit up) of yacht racing. By comparison, in 1018 F1 races, 52 drivers have been killed. That's 5%.

Now I understand you don't trust applied math, but this is simple statistics. The odds of being killed in an F1 race, historically, are 128 times greater than losing a keel fin in the Sydney Hobart. How much safer does elite high performance sailing actually need to be and at what cost?

 

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9 hours ago, Boink said:

 

This does have some parallels as to how the EU has become a bureaucratic juggernaut. 

How you get to your Dystopian reference of camps is worrisome. Lighten up.

EU budget : €148.2 billions

US federal budget : $4450 billions

Despite what the rightwing press says, the EU is simply not a "juggernaut", it is a relatively lightweight political organisation for one that encompass 450 millions inhabitants (compare to the 330 millions of the USA).

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2 hours ago, Moonduster said:

The Showtime incident is surely not due to lack of maintenance as it was a new keel, ie 12 months old?

Not apparent without understanding the design point and the construction. There are lots of programs with keel fins that require regular maintenance and inspection after every event.

the engineering is guesstimation  not tested to failure to create a standard, canting keels proved that

This is total bullshit. The engineering is the engineering. It is based on an assumptions package and a design package. Done correctly, it delivers a solution within those assumptions for that design that works. Period. There is no guesstimation; it is applied math. To claim this is to demonstrate your complete ignorance of not only engineering, but science itself.

Engineering a keel fin and its attachment is no different to any of 1000s of other engineering applications from bridges to buildings to sewers to space ships. None of these are ever tested to failure. Yes, there are occasional engineering mistakes. Far more often, on analysis of failures, the assumptions are proven to be short sighted. But the biggest source of failure is not recalling the design package - for example, launching a space shuttle in sub-freezing weather.

And yet, one must have a design package and an assumption set. Your house has a roof with a design life and an assumption about live load due to snow. These are based on cost and climate and accepted standards of risk. One cannot engineer a roof with an infinite design life or an infinite load bearing ability. That someone chose a 25 year life and a 500 kg/m2 live load limit does not make the engineering behind that roof wrong should it begin to leak.

More to the point, why do you think there's even a problem with keel design? As near as I can tell, 6259 yachts have started the Sydney Hobart. So between races and deliveries, there have been 12518 passages. I can't find any clear answers for keel failures, but let's say 5, which is 0.04% failure rate. That's pretty small for a race that many claim is the "holy grail" (you just can't make this shit up) of yacht racing. By comparison, in 1018 F1 races, 52 drivers have been killed. That's 5%.

Now I understand you don't trust applied math, but this is simple statistics. The odds of being killed in an F1 race, historically, are 128 times greater than losing a keel fin in the Sydney Hobart. How much safer does elite high performance sailing actually need to be and at what cost?

 

yes they used well know engineering standards of a load they didnt understand which I think is what you were saying?

The world is covered in welded structures yet only bad welders weld keels up?

How many common structures have critical welds in them, do keels have critical welds?

If so they need to be inspected like a helicopter as failure will usually mean death?

So when it was built the critical welds were x-rayed and that is on file?? not

Can we separate fabricated fins in this discussion which is where the problem seems to be not keels in general

How many Hobart starters had fabricated fins?

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2 hours ago, Fiji Bitter said:

And that happened how long ago, again?

https://www.smh.com.au/national/yacht-disaster-a-tragedy-waiting-to-happen-20050326-gdl073.html

(From page 1, by fastyacht)

2 hours ago, Fiji Bitter said:

And that happened how long ago, again?

https://www.smh.com.au/national/yacht-disaster-a-tragedy-waiting-to-happen-20050326-gdl073.html

(From page 1, by fastyacht)

 

Not sure what you are on about, but plenty were tested to failure, and some of those reported on very extensively.

 

so somebody had a jig to bolt a keel to and shake it to see how many cycles before failure.

Love to read that report.

 

 

 

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1 hour ago, Panoramix said:

EU budget : €148.2 billions

US federal budget : $4450 billions

Despite what the rightwing press says, the EU is simply not a "juggernaut", it is a relatively lightweight political organisation for one that encompass 450 millions inhabitants (compare to the 330 millions of the USA).

Considering the EU is not a nation (yet) and that all the sovereign costs of each small European nation are not part of that 148 billion, I'd say the cost of the EU is staggering...hahaha.

 

 

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1 hour ago, Panoramix said:

EU budget : €148.2 billions

US federal budget : $4450 billions

Despite what the rightwing press says, the EU is simply not a "juggernaut", it is a relatively lightweight political organisation for one that encompass 450 millions inhabitants (compare to the 330 millions of the USA).

OK, don't Lighten Up.

Instead, you justify one example of excess by comparing it to another even worse case of excess.

Way to go Einstein.

The point you still fail to grasp in the comparison - is that of insidious overreach. As well as the accompanying culture for excessive spending with little apparent oversight or control, that creates no tangible value nor positive outcomes.

Take it to Political Anarchy - where someone might give you the pat on the back that you seek.

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7 hours ago, Fiji Bitter said:

one bad one  affected me personally. And I personally know and talked to several of the lucky survivors, of three boats with clean breaks, and one was still shaking a couple of days after the dramatic rescue. This subject is important to me.

You have personal involvement in 4 different Keel failures? You must either be a investigator, ambulance chaser or a bullshit artist. From your posting history I am going with the latter.

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1 hour ago, LB 15 said:

You have personal involvement in 4 different Keel failures? You must either be a investigator, ambulance chaser or a bullshit artist. From your posting history I am going with the latter.

Or be a really bad welder in the marine business! ;)

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5 hours ago, fastyacht said:

Considering the EU is not a nation (yet) and that all the sovereign costs of each small European nation are not part of that 148 billion, I'd say the cost of the EU is staggering...hahaha.

 

 

Yes, it isn't a nation, it is a minimalist organisation that let member state a lot of freedom (for a start you can leave it without creating a civil war!) but let them club together when needed. It upsets a lot of outside people because it is efficient! Do you really think that Germany or France alone would have managed to make Zuckerberg admit that he had to pay taxes like others?

4 hours ago, Boink said:

OK, don't Lighten Up.

Instead, you justify one example of excess by comparing it to another even worse case of excess.

Way to go Einstein.

The point you still fail to grasp in the comparison - is that of insidious overreach. As well as the accompanying culture for excessive spending with little apparent oversight or control, that creates no tangible value nor positive outcomes.

Take it to Political Anarchy - where someone might give you the pat on the back that you seek.

I didn't start to talk about the EU, I just reacted to the parroting of anti-EU propaganda. There is oversight and there are results, document yourself, you are the one who should go to political anarchy!

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143 billion with a B minimalism. Not sure whart the anti EU sentiment is. Well there is an EU fact--that is that 12215 is a European regulation  taht was made into an ISO standard. Can't get around that. So if you are in Australia or the US your custom racing yacht has to be designed and signed off to that standard--even though apparently the only place you are going to find someone to do that for you is either DNVGL, RINA, or somewhere in France. However I will put this into some perspecitve. In the old metre boat days they had to be built to Lloyd's Rules. The big challenge with Courageous was to get a path forward through the LR with aluminium substituted for the wooden scantlings.   12 metres weren't cheap. A measurable part of that was building under survey.

 

(The civil war comment was stupid)

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1 hour ago, fastyacht said:

Well there is an EU fact--that is that 12215 is a European regulation  taht was made into an ISO standard. Can't get around that.

Can you add to that. In my experience ISO's are generated from existing standards but can't go forward without US support.

I don't know how Rob Schofield is but from his website

Quote

Rob was the U.S. representative on the International Standards Organization (ISO) TC188 WG18 committee, and co-developed the new international boat structures standard, ISO 12215, for marine craft under 24 meters (79 ft). The European Union Parliament mandated in 1994 that all craft manufactured and sold in Europe after July 1998 be designed, built, and certified EU-wide set of standards. The ISO committee was convened in response to that mandate. Rob’s participation was funded by the National Marine Manufacturers Association and by the American Boat & Yacht Council, under a U.S. Coast Guard grant for that work

  This implies that the standard was developed with US input at least.

 

Its also worth noting from the preamble to the standard that custom racing yachts are not intended to be in scope.

Quote

During the latter stages of the development of the ISO 12215 series, and after publication of key parts, a number of authorities adopted this International Standard for the assessment of high-performance racing
yachts. While, in theory, a category A blue-water cruising yacht could experience the same loads as a competitive racing yacht, the latter has not been the principal focus of ISO 12215. Consequently, designers are strongly cautioned against attempting to design high-performance racing craft such that nearly all structural components only just comply.

 

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6 hours ago, Sailabout said:

so somebody had a jig to bolt a keel to and shake it to see how many cycles before failure.

Love to read that report.

You've got a funny way of quoting me.

Never mind that, but you have also never heard of field testing. The keel field test is usually concluded with a float test, I would suggest that you try that one yourself.

 

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4 minutes ago, Fiji Bitter said:

You've got a funny way of quoting me.

Never mind that, but you have also never heard of field testing. The keel field test is usually concluded with a float test, I would suggest that you try that one yourself.

 

Fiji can you guide me to where I could find a description of how a keel field test should be carried out?

I'd be worried about the ability of a field test to say anything other than: "a given keel, with a comparable previous use history, should be able to withstand the loads applied in the field test".

How is a field test set up to test the repetitive loading cycle and load extremes that would be experienced over ocean racing and survival conditions across a couple of decades of use?

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40 minutes ago, JohnMB said:

Can you add to that. In my experience ISO's are generated from existing standards but can't go forward without US support.

I don't know how Rob Schofield is but from his website

  This implies that the standard was developed with US input at least.

 

Its also worth noting from the preamble to the standard that custom racing yachts are not intended to be in scope.

 

Thank you for bringing this up. In fact while an American was involved, it is not a statutory requirement in the US to build to the ISO standard. The involvement of the NMMA was one of those things that if you go back through ol Professional Boatbuilder articles, you can find stuff on it. Do note that the ABYC is preexisting and continues to this day (I won't say any more on that but to say take a look).

The point about "excluding racing yachts was of course not going to stop IYRU from jumping right in and citing the standard. That is a fact. If you read my snips from World Sailing you will see that regardless of any protestations or disclaimers made previously by the rulemakers, IYRU insists on using it for thier puproses.

Note that this sort of bastard use is a COMMON PROBLEM in EVERY DISCIPLINE. Look no further than the Body Mass Index or BMI which the guy who wrote it EXPRESSESLY STATED that it was NOT APPROPRIATE to be generalized and that in fact it merely fit a narttow set of data he was studyignb (all engineers and thinkking people see why the BMI CANNOT WORK--it has a SQUARe thather than a CUBE term in it!!!!!!).

There are other exAMPLES. Look at the rules for lamintated glass, and the specific tests being required----you'll see the same bullshit misapplication of "stancards" going on.

You see, once someonte takes the time to write something, all the other lazy bastards say, "OK GREAT THERE IT IS."

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3 hours ago, fastyacht said:

143 billion with a B minimalism. Not sure whart the anti EU sentiment is. Well there is an EU fact--that is that 12215 is a European regulation  taht was made into an ISO standard. Can't get around that. So if you are in Australia or the US your custom racing yacht has to be designed and signed off to that standard--even though apparently the only place you are going to find someone to do that for you is either DNVGL, RINA, or somewhere in France. However I will put this into some perspecitve. In the old metre boat days they had to be built to Lloyd's Rules. The big challenge with Courageous was to get a path forward through the LR with aluminium substituted for the wooden scantlings.   12 metres weren't cheap. A measurable part of that was building under survey.

 

(The civil war comment was stupid)

It isn't a regulation, it is a standard! The EU on requires compliance but only in the EU! If you don't like our standards, write your own standard!

As for the anti-EU rhetoric, even non EU media accept it as a fact : https://money.cnn.com/2017/02/23/news/economy/europe-eu-trump/index.html

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5 hours ago, LB 15 said:

You have personal involvement in 4 different Keel failures? You must either be a investigator, ambulance chaser or a bullshit artist. From your posting history I am going with the latter.

Or a piss poor welder/engineer....

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1 hour ago, KC375 said:

Fiji can you guide me to where I could find a description of how a keel field test should be carried out?

I'd be worried about the ability of a field test to say anything other than: "a given keel, with a comparable previous use history, should be able to withstand the loads applied in the field test".

How is a field test set up to test the repetitive loading cycle and load extremes that would be experienced over ocean racing and survival conditions across a couple of decades of use?

I would imagine that the racing Showtime did before the S2H would have been considered sufficient testing. It would be highly unlikely that she was not taken out of the water and inspected before the S2H

Fiji sounds like he's talking rubbish as usual.

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Nobody has to have a fabricated keel so you paid for a performance gain on a custom project therefore....

I can see a requirement for annual (and or pre offshore overnight), pressure testing of fabricated keels as insurance companies get smarter...

why not just have the gauge inside the boat so you know when its failing, wireless car tyre system, too simple?

 

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14 hours ago, Fiji Bitter said:

Pulpit,

The drawings will not tell the whole story, of course, but they may tell something.

Like, was it indeed designed to the required standard, and was it approved according to the rules.

And even if it was all 100% correctly approved, several of the pundits here may be critical of the construction anyway. I myself know a little bit about the Drum keel, and this case may be similar.

And legal action? It sounds like AS is not so worried about it, and neither am I... ;)

Many of you Aussie's seem so oversensitive about AS, that it is blurring your vision. I don't follow the AS thread, and neither all the Queensland shit, but from this tread alone it is obvious that there is a deep mistrust. I do remember something crooked with the Olympic selection, much like that infamous case in the US, I believe. And yes, that and a lot of other stuff would make me mad too.

But many here just want to find out as much as possible why the keel failed. There have been far to many keel accidents, and far to many bad ones I am afraid, and one bad one  affected me personally. And I personally know and talked to several of the lucky survivors, of three boats with clean breaks, and one was still shaking a couple of days after the dramatic rescue. This subject is important to me.

 

Let’s hear the details on the four missing keels. I’m calling bullshit. 

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1 hour ago, Sailabout said:

Nobody has to have a fabricated keel so you paid for a performance gain on a custom project therefore....What?

I can see a requirement for annual (and or pre offshore overnight), pressure testing of fabricated keels as insurance companies get smarter... What is pressure testing? How is it applied to a monolithic milled fin?

why not just have the gauge inside the boat so you know when its failing, wireless car tyre system, too simple? That should be perfect when your 1,000 nm away from land! Just call the lads at home to pic you up in a few........

 

 

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7 hours ago, Hitchhiker said:

 

We are talking about fabricated hollow fins as in made from sheets of steel not milled from a billet ( med cup rule) or a cast one.

You must have been wondering where the welding got involved in a milled fin?

Anyone ever heard of a milled fin failing?

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23 hours ago, Moonduster said:

 

More to the point, why do you think there's even a problem with keel design? As near as I can tell, 6259 yachts have started the Sydney Hobart. So between races and deliveries, there have been 12518 passages. I can't find any clear answers for keel failures, but let's say 5, which is 0.04% failure rate. That's pretty small for a race that many claim is the "holy grail" (you just can't make this shit up) of yacht racing. By comparison, in 1018 F1 races, 52 drivers have been killed. That's 5%.

Now I understand you don't trust applied math, but this is simple statistics. The odds of being killed in an F1 race, historically, are 128 times greater than losing a keel fin in the Sydney Hobart. How much safer does elite high performance sailing actually need to be and at what cost?

 

I generally agree with your post, but this stat is a fair way off. Your 5% is based on fatalities : races started. The odds of being killed would be fatalities drivers starting races.

1018 races with 20 drivers on average (don’t know how accurate that is) = 20,360 starts. To 52 fatalities, that’s 0.2%. So if there’s been 5 keels lost over the years the risk of dying in an F1 race is something like 5 times greater than losing your keel in a Hobart.

Of course the comparison isn’t apples for apples, so I’m not sure how helpful it is at all. IMO it’s enough to just note a 0.04% failure rate to prove the risk is piddling.

I wouldn’t be surprised if the overall keel failure rate, across all sailboats everywhere doing anything, is less than 0.04% 

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People dying because keels fall off, particularly close friends or people you have known for the best part of your life and were stalwarts of the sport, is a good enough reason to find out what & why it happened. 

So f8ck off with your statistics.

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On 1/7/2020 at 1:05 PM, fastyacht said:

Yes--thank you! That's the one. Not as recdent as I remember. God time flies.

https://www.smh.com.au/national/yacht-disaster-a-tragedy-waiting-to-happen-20050326-gdl073.html

From memory I read the white paper on the Excalibur incident which was a failed weld and at some stage a more junior member of the build team could have been doing the work? But please don't hold me on this my memory isn't as good as it used to be. The builder was charged with Manslaughter also from memory. Lot's of water to go under the bridge on this incident so speculation albeit aspects of it appear obvious is probably best left to when we get some sort of report?

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1 hour ago, Sailabout said:

We are talking about fabricated hollow fins as in made from sheets of steel not milled from a billet ( med cup rule) or a cast one.

You must have been wondering where the welding got involved in a milled fin?

Anyone ever heard of a milled fin failing?

Must say having had a boat that was built with a solid stainless 316 fin that when we hit sunfish I was never worried about the keel but more so the rudder. I was told by a particular member of my team the rudder was way over engineered. It (The Rudder) broke not long after one such Sunfish escapade via  a box weld failure. Whilst I know some people say welding is fine I would much prefer a structure with no possible points of failure. Money shouldn't be an option if you are racing a boat in a race like the Hobart with lives at stake IMO.

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1 hour ago, terrafirma said:

Must say having had a boat that was built with a solid stainless 316 fin that when we hit sunfish I was never worried about the keel but more so the rudder. I was told by a particular member of my team the rudder was way over engineered. It (The Rudder) broke not long after one such Sunfish escapade via  a box weld failure. Whilst I know some people say welding is fine I would much prefer a structure with no possible points of failure. Money shouldn't be an option if you are racing a boat in a race like the Hobart with lives at stake IMO.

your fin was milled from stainless? fark

you rudder was stainless and had welds, thats not safe under water, hard to believe anyone would do that?

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It is no coincidence that the VO70 rule required solid steel fin structures with no welds and the VO65  and IMOCA OD fins are forged and milled with no welds.

Also interesting that the Rambler 100 fin broke where a crack found in milling of the forged billet was ground out and welded over.

It is also interesting that some moan about the ISO/EN rules when prior to them we all relied on ABS (AMERICAN Bureau of Shipping) rules and no one complained (too loud). DNV-GL, RINA or ICNN will provide certification worldwide, as they did with the Showtime keel designed and built in Australia. Not really a big hurdle to deal with in this day and age.

 

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7 hours ago, Sailabout said:

 

You must have been wondering where the welding got involved in a milled fin?

 

No. Just wondering where you were coming from with that whacky pressure testing theory.  But, seeing your choice of avatar from Whacky Races it becomes more clear :ph34r:.

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On 2/18/2020 at 5:33 AM, Moonduster said:

The Showtime incident is surely not due to lack of maintenance as it was a new keel, ie 12 months old?

Not apparent without understanding the design point and the construction. There are lots of programs with keel fins that require regular maintenance and inspection after every event.

the engineering is guesstimation  not tested to failure to create a standard, canting keels proved that

This is total bullshit. The engineering is the engineering. It is based on an assumptions package and a design package. Done correctly, it delivers a solution within those assumptions for that design that works. Period. There is no guesstimation; it is applied math. To claim this is to demonstrate your complete ignorance of not only engineering, but science itself.

Engineering a keel fin and its attachment is no different to any of 1000s of other engineering applications from bridges to buildings to sewers to space ships. None of these are ever tested to failure. Yes, there are occasional engineering mistakes. Far more often, on analysis of failures, the assumptions are proven to be short sighted. But the biggest source of failure is not recalling the design package - for example, launching a space shuttle in sub-freezing weather.

And yet, one must have a design package and an assumption set. Your house has a roof with a design life and an assumption about live load due to snow. These are based on cost and climate and accepted standards of risk. One cannot engineer a roof with an infinite design life or an infinite load bearing ability. That someone chose a 25 year life and a 500 kg/m2 live load limit does not make the engineering behind that roof wrong should it begin to leak.

More to the point, why do you think there's even a problem with keel design? As near as I can tell, 6259 yachts have started the Sydney Hobart. So between races and deliveries, there have been 12518 passages. I can't find any clear answers for keel failures, but let's say 5, which is 0.04% failure rate. That's pretty small for a race that many claim is the "holy grail" (you just can't make this shit up) of yacht racing. By comparison, in 1018 F1 races, 52 drivers have been killed. That's 5%.

Now I understand you don't trust applied math, but this is simple statistics. The odds of being killed in an F1 race, historically, are 128 times greater than losing a keel fin in the Sydney Hobart. How much safer does elite high performance sailing actually need to be and at what cost?

 

When ever anyone here quotes F1 it usually turns out to be bullshit..why you would equate F1 driver deaths to keel failures in the SH and return baffles me. Your numbers are totally bogus, F1 driver deaths occur in races, practice and and thousands of hours of testing....it used to be that 4-5 deaths would occur each year but as safety has increased out of all recognition there have been 5 deaths in the last 30 yrs.

You say it’s simply statistics, in your case...it’s not...

 

 

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It is no coincidence pathetic that the VO70 rule required solid steel fin structures with no welds and the VO65  and IMOCA OD fins are forged and milled with no welds.

That the VOR went one-design and the IMOCA went one-design on masts and keels is even more pathetic. These were/are the top development classes in the sport. Some development. Some sport.

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32 minutes ago, Moonduster said:

Some development. Some sport.

just raise the money that will allow the development to return and everything will be solved. 

Oh, you don't know where to find the money?  That's what they said.

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15 minutes ago, MR.CLEAN said:

just raise the money that will allow the development to return and everything will be solved. 

Oh, you don't know where to find the money?  That's what they said.

Don't stop a good sanctimonious Moonduster rant bro.

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2 hours ago, Chimp too said:

when prior to them we all relied on ABS (AMERICAN Bureau of Shipping) rules and no one complained (too loud

ABS Offshore Racing Yachts was very minimal on the subject of keel construction. About 1 page total where rudders were many pages. Only 2 design conditions: the 90 degree knockdown case and the grounding case.

image.thumb.png.e5ff02ae8192f29709d0a81fcca1f0db.pngimage.png.473487e3481509a092db2e486f16fd93.png

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well if that's the case then your failure to bring together the sources of money and the development-favoring teams is one of the reasons for the pathetic state you find the sport in today.

It's not too late though.  Make those calls!

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4 hours ago, Moonduster said:

It is no coincidence pathetic that the VO70 rule required solid steel fin structures with no welds and the VO65  and IMOCA OD fins are forged and milled with no welds.

That the VOR went one-design and the IMOCA went one-design on masts and keels is even more pathetic. These were/are the top development classes in the sport. Some development. Some sport.

Inevitable consequence of commercial funding.   A longer-term view/frame of reference says that the sport is harmed by failures of on-the-edge structures as the public only sees the headlines and/or potential fatalities.  Corporate sponsors can't have their brands associated with those sorts of failures.  

Of course, one design masts and keels in IMOCO have slowed development and constrained designers at one level, but they have also spawned clever design developments.  What is clear is that these constraints have delivered a demonstrably reliable fleet over the last few years that in general hasn't been hitting the headlines for all the wrong reasons.  

So sure, walk away from one-design risk mitigation in the interests of pure development.  And walk away from financial sustainability at the same time.

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Somehow Elf and Kool and Winston and Tide and Nextel and and and have been okay with smashing cars every weekend and a string of dead drivers. I don't get it.

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11 hours ago, terrafirma said:

I would much prefer a structure with no possible points of failure

No such structure exists.  Everything has a failure mode.  One of the practices in building resilient systems is to assume the element has failed and then assess the impacts across the rest of the system. 

All too often people try to guess why it might fail.  If they can't, they assume the risk to be minimal.  this can lead to solution designs that are inherently less resilient to failure than other options.  Even experienced engineers are not immune to this and there are many famous examples (like the challenger disaster) where an assumed low risk proved to be vastly inaccurate. 

I know little or nothing about keel design, but back of the envelope, even a forged keel will have failure points.  The bolts, the hull structure, the right angle flange at the top of the fin, thinner material mid span to the bulb.  Lots of opportunity for failure, but perhaps more reserved capacity for failure in the system.

There was also a presentation at the Institute of engineers (I think) a few years back.  One of the big boat programs here put a load cell on their keel and I think were genuinely surprised by the extremes of the dynamic loadings.  That led them to update their keel maintenance & inspection program but I think was still within design parameters.  I seem to remember a paper on it,  (maybe this one?) but I can't be arsed looking for it too hard.

That paper  above though suggests the loadings were as high as the "ultimate loading" they thought the keel would endure, but also that the nature of those loadings was pretty specific to each boats design.  I guess that leads to one of the earlier assertions about guesstimating the loads.

At any rate, I guess that's a long way of saying in any dynamic critical system,  you're always better off assuming a component might fail, and acting accordingly than the opposite

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31 minutes ago, Spoonie said:

No such structure exists.  Everything has a failure mode.  One of the practices in building resilient systems is to assume the element has failed and then assess the impacts across the rest of the system. 

All too often people try to guess why it might fail.  If they can't, they assume the risk to be minimal.  this can lead to solution designs that are inherently less resilient to failure than other options.  Even experienced engineers are not immune to this and there are many famous examples (like the challenger disaster) where an assumed low risk proved to be vastly inaccurate. 

I know little or nothing about keel design, but back of the envelope, even a forged keel will have failure points.  The bolts, the hull structure, the right angle flange at the top of the fin, thinner material mid span to the bulb.  Lots of opportunity for failure, but perhaps more reserved capacity for failure in the system.

There was also a presentation at the Institute of engineers (I think) a few years back.  One of the big boat programs here put a load cell on their keel and I think were genuinely surprised by the extremes of the dynamic loadings.  That led them to update their keel maintenance & inspection program but I think was still within design parameters.  I seem to remember a paper on it,  (maybe this one?) but I can't be arsed looking for it too hard.

That paper  above though suggests the loadings were as high as the "ultimate loading" they thought the keel would endure, but also that the nature of those loadings was pretty specific to each boats design.  I guess that leads to one of the earlier assertions about guesstimating the loads.

At any rate, I guess that's a long way of saying in any dynamic critical system,  you're always better off assuming a component might fail, and acting accordingly than the opposite

Off course everything has the ability to fail. But some more so than others and with greater loads and impact resistance. We don't use Kevlar in new race boats today because it's heavier than carbon for example but Kevlar has it's advantages. Jason Ker mentioned that the client chose a more cost effective option in this case. The client went outside the original designer and so the boat shouldn't be a Ker anymore. Chutzpah was designed by Reichel Pugh but is called a Caprice for example. Some designers are stricter than others when it comes to mods outside of the original designer. 

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2 hours ago, fastyacht said:

Somehow Elf and Kool and Winston and Tide and Nextel and and and have been okay with smashing cars every weekend and a string of dead drivers. I don't get it.

come back and make that comparison after you've packed the stands with 150k paying fans of sailing

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8 hours ago, Hitchhiker said:

No. Just wondering where you were coming from with that whacky pressure testing theory.  But, seeing your choice of avatar from Whacky Races it becomes more clear :ph34r:.

Seems like you still dont understand what a fabricated fin is, they are hollow so can be pressure tested.

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1 hour ago, Spoonie said:

There was also a presentation at the Institute of engineers (I think) a few years back.  One of the big boat programs here put a load cell on their keel and I think were genuinely surprised by the extremes of the dynamic loadings.  That led them to update their keel maintenance & inspection program but I think was still within design parameters.  I seem to remember a paper on it,  (maybe this one?) but I can't be arsed looking for it too hard.

We put a load cell on the sheave pin on one of our oceanographic winches once. The results showed us just how close to the edge of failure we'd been (broken data cable that was also the load carrying cable - data wires down the core). The result was we downgraded the total allowable mass of the instrument package attached. This caused some angst from the scientists but that was too bad. Better than leaving *another* expensive instrument package on the bottom of the ocean.

If you can't measure it, you're guessing.

FKT

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16 minutes ago, Fah Kiew Tu said:

We put a load cell on the sheave pin on one of our oceanographic winches once. The results showed us just how close to the edge of failure we'd been (broken data cable that was also the load carrying cable - data wires down the core). The result was we downgraded the total allowable mass of the instrument package attached. This caused some angst from the scientists but that was too bad. Better than leaving *another* expensive instrument package on the bottom of the ocean.

If you can't measure it, you're guessing.

FKT

YES YES YES

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Just now, Fah Kiew Tu said:

We put a load cell on the sheave pin on one of our oceanographic winches once. The results showed us just how close to the edge of failure we'd been (broken data cable that was also the load carrying cable - data wires down the core). The result was we downgraded the total allowable mass of the instrument package attached. This caused some angst from the scientists but that was too bad. Better than leaving *another* expensive instrument package on the bottom of the ocean.

If you can't measure it, you're guessing.

FKT

 

Just now, Sailabout said:

YES YES YES

NO NO NO

On 2/19/2020 at 12:33 AM, Moonduster said:

the engineering is guesstimation  not tested to failure to create a standard, canting keels proved that

This is total bullshit. The engineering is the engineering. It is based on an assumptions package and a design package. Done correctly, it delivers a solution within those assumptions for that design that works. Period. There is no guesstimation; it is applied math. To claim this is to demonstrate your complete ignorance of not only engineering, but science itself.

 

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Some interesting info.

https://www.sailing.org/classesandequipment/offshore/plan_review.php

 

A little up from the bottom, in black and white, is a clear indication that there were many layers of QC applied prior to construction.

  • A standard ISO 12215
  • An engineer
  • A class society

Then during construction there should be QC processes of the builder. This may've even been inspected or qualified by the class society.

Then after construction there is inspection processes of the owner.

Hopefully the review looks at all 5 of those, because here we have a keel that went through all the processes laid down by WS...and still failed...

Why?

World Sailing are missing a golden opportunity to review their process. They should be biting the bullet and getting that hull back to shore to enable a thorough forensic engineering analysis without the risks associated with a fatal incident coroners review. No-ones going to jail over this, insurance can't void the policy because the process has clearly been followed, emotions are lower, experts can be involved and make their own recommendations rather than relying on a coroners interpretation. This needs to happen.

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29 minutes ago, Fiji Bitter said:

 

NO NO NO

 

you still dont get it the loads were guessed in canters when fully canted and the boat jumps of a wave, sure they used  well known structural calculation to design them, didnt work as the loads were outside their design criteria.
In many cases it was fatigue failures from very high cycling loads that were not taken into consideration

Is there any industry that has as many catastrophic failures as keels on yachts considering the money and engineering that goes into them??

We are working  with materials that are well known so some part of the equation has been guessed hasnt it!

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1 hour ago, Sailabout said:

Seems like you still dont understand what a fabricated fin is, they are hollow so can be pressure tested.

You would be wrong.  Again.

This is one I'm working on currently. 

What, exactly are the standards and pressures that would be used to NDT this structure?

IMG_2015.jpg

IMG_5305.jpeg

Btw, note that the NA of this keel made sure that there was No Top Plate!

 

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Sailing yachts are experimental craft ( well quite a few of them especially race boat one offs).

There aren't any standards. (Pretend 12215 is a standard. But it isn't. Only for a narrow subset of possible design choices).

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what failure was there with that?

Anyway thats what i'm saying the industry doesnt have any standard so what do you do?
Assuming it was built with common engineering standards the same engineer can calculate how much max pressure to put in it?

They pressure test ships tanks (and rudders as they are hollow) with low pressure but over several days it will find a leak.
Industry standards,

but yachts..guesswork, looks good, paint it?

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There are wise assembly designs and there are foolish assembly designs. Designing a Chinese Puzzle that cannot be examined and tested non destructively for critical strength continuity and absence of crack starters may not be a wise idea...

I don't know anything about this particular design. MAybe the fab was bad. Maybe the design. Maybe both. Maybe the materials were not to spec. Maybe the NDT was not carried out properly and failed to show a critical flaw.

All speculation.

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3 hours ago, Fiji Bitter said:

This is total bullshit. The engineering is the engineering. It is based on an assumptions package and a design package. Done correctly, it delivers a solution within those assumptions for that design that works. Period. There is no guesstimation; it is applied math. To claim this is to demonstrate your complete ignorance of not only engineering, but science itself.

Nah... as an applied mathematician, it's a guesstimation.  you build a model, plop in some boundary assumptions & conditions, and spit out some numbers.  Your model could be wrong, your assumptions could be wrong, or both.  Chances are you're wrong somewhere.  They're certainly called assumptions for a good reason.  

Newtonian physics being what it is, they could be highly educated guesses, but they're still just an approximation of the real thing.  Especially when you add hydrodynamic loading into that picture.

You can see from the paper I posted above, the numbers used were relatively arbitrary.  1G loadings with a safety factor of 3 using "quasi-static analysis".   In testing, Hugo Boss bumped up against those numbers from time to time.  WOXI was a little more comfortable inside the comfort factor, but definitely over the 1G spec.

1g and 3x are too convenient for me.   IMHO someone's made an educated guess.  Maybe there was some real data that informed those numbers who knows.  In some circles though, breaching the comfort factor would be considered an engineering failure. 

Either way, as fastyacht pointed out, race boats are experimental engineering.  There's precisely one of them (in many cases) built to withstand at a bare minimum, the structural needs to get them around whatever race course they're on.  With all due respect to the NA's here, to suggest they have a perfect understanding of the dynamic loads placed on those boats, I think would be giving them a lot of credit.  Especially the big fancy ones (Boats, not NA's) 

*shrug*

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2 hours ago, Hitchhiker said:

Btw, note that the NA of this keel made sure that there was No Top Plate!

 

so now its rusty and cant be cleaned and inspected to determine if its still strong enough so it goes in the bin or there is there an ISO standard to work to?

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22 minutes ago, Sailabout said:

so now its rusty and cant be cleaned and inspected to determine if its still strong enough so it goes in the bin or there is there an ISO standard to work to?

Why don't you get out your pressure kit with no standards and come down and test it? We're using real world experience and common sense engineering. That was my point earlier.  There are no standards.  

Really don't know what you are trying to say here.  Maybe some real world experience on your part would help.

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I’m wondering what a pressure test would reveal except that the welds remains airtight. Doesn’t address whether there’s fatigue? Whether the welds may have caused temperature enbriddlement? Perhaps inappropriate concentration of stress?

 

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1 minute ago, Miffy said:

I’m wondering what a pressure test would reveal except that the welds remains airtight. Doesn’t address whether there’s fatigue? Whether the welds may have caused temperature enbriddlement? Perhaps inappropriate concentration of stress?

 

It's the airtight bit. If the pressure changes, there's most likely to be a fatigue crack somewhere. Early warning before catastrophic failure because cracks propagate, sometimes really fast. Time to haul out & do a dye pen test or similar.

When we had a new sea chest fitted to one of our ships it had to be x-rayed afterwards to check the weld soundness. Luckily the welders did a professional job because when you're x-raying 40mm plate you need a serious machine and the safety precautions equally so. Don't want to have to do it twice. Dry dock job in Garden Island Sydney.

FKT

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But depending on the alloy and weld, it isn’t a good early detection because fatigue cracks propagation is not going to be the same path as internal pressure. 
 

I mentioned this earlier in the thread, you’re better off putting epoxy coated metal spokes tensions along the load path flat against the keel. Spec the spoke to fracture before the keel - actually observable without a haul out. 

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4 hours ago, Miffy said:

I’m wondering what a pressure test would reveal except that the welds remains airtight. Doesn’t address whether there’s fatigue? Whether the welds may have caused temperature enbriddlement? Perhaps inappropriate concentration of stress?

 

pressure test says get ready for a failure rather then snap too late, versus currently fingers crossed she'll be right on the night?

A few more failures and maybe IRC will likely hammer them as in get rid of them as the technology is too immature for the industry as they keep proving.

Or start to ask for x rays?

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5 hours ago, Hitchhiker said:

Why don't you get out your pressure kit with no standards and come down and test it? We're using real world experience and common sense engineering. That was my point earlier.  There are no standards.  

Really don't know what you are trying to say here.  Maybe some real world experience on your part would help.

pressure test I agree is just for imminent failure assuming it cracks first but better than nothing.

What is the issue you have, failure or just inspection?
You mentioned the NA asked not to enclose it, what did he have in mind for maintenance?

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14 hours ago, fastyacht said:

Somehow Elf and Kool and Winston and Tide and Nextel and and and have been okay with smashing cars every weekend and a string of dead drivers. I don't get it.

Because it’s profitable. Towards the end of the last millennium one of my tasks as assigned was a biggish marketing budget so I got to see lots of research on this stuff. The NASCAR demographic beat all others in their willingness to align their shopping behaviour to the sponsors of their favoured team...AND if the category was not branded on their favoured team they would seek product from brands supporting anything NASCAR. Closer to cult/religion than rational economic decision making. The occasional sacrifice merely demonstrates the purity of the endeavour. Few things are more profitable than religion. (in fairness NASCAR teams work pretty hard at protecting their drivers)

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13 hours ago, Spoonie said:

No such structure exists.  Everything has a failure mode.  One of the practices in building resilient systems is to assume the element has failed and then assess the impacts across the rest of the system. 

...

At any rate, I guess that's a long way of saying in any dynamic critical system,  you're always better off assuming a component might fail, and acting accordingly than the opposite

Wise words, for any system or operation.

One of the most talented software development teams I’ve come across emphasised this. They educated me on just how many “bugs” were in typical devices we assumed were actually sorted out.

They talked about designing to “fail gracefully”. If you could not build in multiple redundancies then at least instrument the system to let you know it is in the process of dying on you so you had time to respond – ideally so users never know.

I’ve tried to keep that theme in mind when thinking about any process or operations – especially ones involving people as they seem very prone to malfunction or unexpected outputs.

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8 hours ago, Spoonie said:

... There's precisely one of them (in many cases) built to withstand at a bare minimum, the structural needs to get them around whatever race course they're on.  ...

And one of the design challenges is to get them around the course the fastest (and maybe within a budget)..so designers may have to make choices with imperfectly understood loads, about how far to increase margins of safety, while minimizing weight and or choosing cost effective materials...

Some would argue if it never breaks then you’ve given up too much performance.

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10 hours ago, KC375 said:

And one of the design challenges is to get them around the course the fastest (and maybe within a budget)..so designers may have to make choices with imperfectly understood loads, about how far to increase margins of safety, while minimizing weight and or choosing cost effective materials...

Some would argue if it never breaks then you’ve given up too much performance.

"The car should fail just as it crosses the finish line"

Colin Chapman

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Or use the Benny Lexen process,  make it as light as you think you can,  if it doesn't break- drill a hole in it.

Repeat until failure & you then know how many holes to drill in the new one!

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On 2/20/2020 at 1:02 PM, Hitchhiker said:

Why don't you get out your pressure kit with no standards and come down and test it? We're using real world experience and common sense engineering. That was my point earlier.  There are no standards.  

Really don't know what you are trying to say here.  Maybe some real world experience on your part would help.

all jokes aside, I dont fancy being in your position to inspect that and put it back on unless following the builder/NA's instruction re future liability?

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On 2/19/2020 at 12:14 AM, Fiji Bitter said:

..............

Not sure what you are on about, but plenty were tested to failure, and some of those reported on very extensively.

 

 

On 2/19/2020 at 10:41 AM, Fiji Bitter said:

You've got a funny way of quoting me.

Never mind that, but you have also never heard of field testing. The keel field test is usually concluded with a float test, I would suggest that you try that one yourself.

 

 

On 2/19/2020 at 10:52 AM, KC375 said:

Fiji can you guide me to where I could find a description of how a keel field test should be carried out?

I'd be worried about the ability of a field test to say anything other than: "a given keel, with a comparable previous use history, should be able to withstand the loads applied in the field test".

How is a field test set up to test the repetitive loading cycle and load extremes that would be experienced over ocean racing and survival conditions across a couple of decades of use?

 

Sorry KC375, I've been a kind of busy this week with a refit and some family matters, and since you are an eloquent poster in the Brexit thread, I feel I owe you a decent answer.

When I said "plenty were tested to failure", I really meant, a bit tongue in cheek, just all keel failures. I thought I made that clear when I joked about the float test.

Nevertheless, your question remains a valid one, but my experience is limited to nonscientific "field tests", some quite spectacular, but personaly I never concluded one with a float test, and the only collected "data" was in the form of damaged keels, keel structures, bolts, or crew.

One example of a proper keel test is this one by SP/Gurit. Don't remember where I came across it, may have been in the Hugo Boss thread. And it may well be that they have done something similar with the new one, but they are not telling us yet, naturally.

https://www.researchgate.net/publication/265323930_MEASUREMENT_OF_ACCELERATIONS_AND_KEEL_LOADS_ON_CANTING_KEEL_RACE_YACHTS

There must be plenty more, but most of it will be held privately, I suppose. Anyone knows of similar tests?

As for your last question, I don't think you can expect any of those modern high performance keels to last a couple of decades, not without overbuilding them and/or proper inspection. And proper inspection of any of those keels, periodically or after an adverse event, is a subject I would like to hear more about myself.

 

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2 hours ago, Fiji Bitter said:

 

 

 

Sorry KC375, I've been a kind of busy this week with a refit and some family matters, and since you are an eloquent poster in the Brexit thread, I feel I owe you a decent answer.

When I said "plenty were tested to failure", I really meant, a bit tongue in cheek, just all keel failures. I thought I made that clear when I joked about the float test.

Nevertheless, your question remains a valid one, but my experience is limited to nonscientific "field tests", some quite spectacular, but personaly I never concluded one with a float test, and the only collected "data" was in the form of damaged keels, keel structures, bolts, or crew.

One example of a proper keel test is this one by SP/Gurit. Don't remember where I came across it, may have been in the Hugo Boss thread. And it may well be that they have done something similar with the new one, but they are not telling us yet, naturally.

https://www.researchgate.net/publication/265323930_MEASUREMENT_OF_ACCELERATIONS_AND_KEEL_LOADS_ON_CANTING_KEEL_RACE_YACHTS

There must be plenty more, but most of it will be held privately, I suppose. Anyone knows of similar tests?

As for your last question, I don't think you can expect any of those modern high performance keels to last a couple of decades, not without overbuilding them and/or proper inspection. And proper inspection of any of those keels, periodically or after an adverse event, is a subject I would like to hear more about myself.

 

Thanks looks like an interesting read. I look forward to digesting it.

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On 2/23/2020 at 9:24 PM, Fiji Bitter said:

 

 

 

Sorry KC375, I've been a kind of busy this week with a refit and some family matters, and since you are an eloquent poster in the Brexit thread, I feel I owe you a decent answer.

When I said "plenty were tested to failure", I really meant, a bit tongue in cheek, just all keel failures. I thought I made that clear when I joked about the float test.

Nevertheless, your question remains a valid one, but my experience is limited to nonscientific "field tests", some quite spectacular, but personaly I never concluded one with a float test, and the only collected "data" was in the form of damaged keels, keel structures, bolts, or crew.

One example of a proper keel test is this one by SP/Gurit. Don't remember where I came across it, may have been in the Hugo Boss thread. And it may well be that they have done something similar with the new one, but they are not telling us yet, naturally.

https://www.researchgate.net/publication/265323930_MEASUREMENT_OF_ACCELERATIONS_AND_KEEL_LOADS_ON_CANTING_KEEL_RACE_YACHTS

There must be plenty more, but most of it will be held privately, I suppose. Anyone knows of similar tests?

As for your last question, I don't think you can expect any of those modern high performance keels to last a couple of decades, not without overbuilding them and/or proper inspection. And proper inspection of any of those keels, periodically or after an adverse event, is a subject I would like to hear more about myself.

 

 

I don't know where you go it, but I posted it in reply to you up above.  

It's not a proper keel test.  They're attempting to validate design assumptions on acceleration and forces, as opposed to confirming the failure mode of the as built design meets expectations.

One of those boats in that paper would go on to have a catastrophic ram failure though.  

A good example of a proper test would be the work that went into the de Havilland Comet

https://en.wikipedia.org/wiki/De_Havilland_Comet

I would suggest such a test is cost prohibitive in most yacht design scenarios.

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13 hours ago, Spoonie said:
.....A good example of a proper test would be the work that went into the de Havilland Comet


https://en.wikipedia.org/wiki/De_Havilland_Comet

I would suggest such a test is cost prohibitive in most yacht design scenarios.

This thread is getting very circular.

On 1/14/2020 at 3:51 PM, jack_sparrow said:

Interestingly in the regular listing of top 25 or 50 product fails structural failure rarely makes the grade. Drinks and electronic devices are the majority, though the 1980's smokeless cigarette is a regular.

The only regular potential structural failure and a fair way down the list was the the world’s first commercial jet airliner, the British De Havilland Comet DH106. Launched in 1952 3 years after its 1949 first flight, it had within a year several unexplained crashes and even exploding in midair. 

Three Comets that were lost within twelve months were after suffering catastrophic in-flight break-ups. Two of these were found to be caused by structural failure resulting from metal fatigue in the airframe in less than a year, a phenomenon not fully understood at the time. The other one was due to overstressing of the airframe during flight through severe weather.

The Comet was withdrawn from service and extensively tested. Design and construction flaws, including improper riveting and dangerous concentrations of stress around some of the square windows, were ultimately identified. As a result, the Comet was extensively redesigned, with oval windows, structural reinforcements and other changes. Rival manufacturers meanwhile heeded the lessons learned from the Comet while developing their own aircraft.

Learning from mistakes is the name of the game.

DH-106-Comet.jpeg

 

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15 hours ago, Spoonie said:
 

I don't know where you go it, but I posted it in reply to you up above.  

It's not a proper keel test.  They're attempting to validate design assumptions on acceleration and forces, as opposed to confirming the failure mode of the as built design meets expectations.

One of those boats in that paper would go on to have a catastrophic ram failure though.  

A good example of a proper test would be the work that went into the de Havilland Comet

https://en.wikipedia.org/wiki/De_Havilland_Comet

I would suggest such a test is cost prohibitive in most yacht design scenarios.

That was almost predicted by the paper.

"the loads in the keel structure were significantly lower than would be calculated using a quasi-static analysis with the measured accelerations. This discrepancy is due to the flexibility of the keel structure, which effectively results in the keel bulb seeing a lower acceleration than the rigid body acceleration that the boat would suggest."

I interpreted that to imply the “keel structure” – presumably including the ram – was taking on more than expected.

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Showtime has been recovered.

Picture I was shown, shows what appears to be a clean break where the keel joins the hull. Minimal tearing of the outer skin on the port side suggesting that's the way it separated.

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12 minutes ago, Gorn FRANTIC!! said:

Showtime has been recovered.

Picture I was shown, shows what appears to be a clean break where the keel joins the hull. Minimal tearing of the outer skin on the port side suggesting that's the way it separated.

Now there might be something to learn from

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On 2/18/2020 at 11:51 AM, Panoramix said:

EU budget : €148.2 billions

US federal budget : $4450 billions

Despite what the rightwing press says, the EU is simply not a "juggernaut", it is a relatively lightweight political organisation for one that encompass 450 millions inhabitants (compare to the 330 millions of the USA).

Talk about comparing apples and pears. Have a think about all the things the US federal government pays for that European nations individually pay for. I will start you off with defence as one example.

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25 minutes ago, bdu98252 said:

Talk about comparing apples and pears. Have a think about all the things the US federal government pays for that European nations individually pay for. I will start you off with defence as one example.

Take it to PA