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45 minutes ago, fastyacht said:

It's got its own good and bad. Youd have to desicribe in more details to know. Just for shits and gigles there have been some catastrphic copmpsite failed keels. Melges 30...look that one up. It became the 32 (same mold I understand) but they sorted out the keel. Apparently from scuttlebut the Melges guys dodn't do the keel itself. I heard (in the mid 90s) about the bad design but someone else might have better info.

One advantage to composites is that, provided you have a baseline, it is possible to measure fatigue through deflection. Never heard it done on a keel though but on rotorblades yes

Fatigue behavior of compsietes varies widely too. Carbon is the sort of stuff that goes Bang! Fiberglass often goes "crackle crackle oh shit do something" more like wood--but details matter. Everything matters.

Composites are both a material and a structure. Boat construction is still "experimental" to a significant extent. You see those airplanes on youtube with "EXPERIMENTAL" on the spar behind the pilot? Every sailboat probably aught to say that right where the IMO or CG documentation number goes...

Let me add that the S-N (stress versus number of cycles) curves for most composites have a different character than for steel. Maybe I'll go put some up for comparison if I can make a decent comparison.

A lot of the good work out there that allows contrasting materials is in the bicycle industry. Some manufacturers have the same basic rider frame geometry modeled out in fluid formed 6000, cromoly and carbon composite. 
 

the keel specialist producers that have cast iron molds for lead castings are probably the only folks who do enough volume to begin to approximate that level of detail in the industry. 

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Sad to see one of our designs lost, and relieved that crew are all ok.  I should clarify However that that particular keel was not designed by us or built by McConaghy,  Apparently there were lower co

We've designed many keels and not lost one. Our reputation is important to us, and in all other cases of keel replacement that I know of for our designs, we've done the designs and it would be natural

Certainly when someone modifies our design without our involvement it ceases to be our problem technically, but it remains important to make sure people are aware of that as our name is in on the boat

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1 minute ago, fastyacht said:

In "the new sciens of strong materials" J.E. Gordon used the Comet as an example of what should have been known from Griffith's work and otehr staete of the art knowledge. IT took the Comet and some other things to get it to sink in. (Liberty ships too--but for them it was the DBTT or ductiel to brittle transition temperature which is a characteristie weirdnessof BCC crystal structures (and to a far lesser extent HCP as well). FCC structures (aluminum, austenitic sstanklesss steel) are immune.

 

At least none of them decided to try and fix basic center of gravity issues with mounting a large high bypass on an obsolete fuselage and wing right?!

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3 minutes ago, Miffy said:

A lot of the good work out there that allows contrasting materials is in the bicycle industry. Some manufacturers have the same basic rider frame geometry modeled out in fluid formed 6000, cromoly and carbon composite. 
 

the keel specialist producers that have cast iron molds for lead castings are probably the only folks who do enough volume to begin to approximate that level of detail in the industry. 

Tehre were some pretty spectacular fuckups in early composite and ally bicycles. And steel & alumium frames were prefectly designed fatigue machiens. I should know. I broke more htan four! of them that way. So did my brother.

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2 hours ago, fastyacht said:

Tehre were some pretty spectacular fuckups in early composite and ally bicycles. And steel & alumium frames were prefectly designed fatigue machiens. I should know. I broke more htan four! of them that way. So did my brother.

I've always been given to understand that if a steel bicycle frame is done right it flexes within its elastic limit and fatigue is a non-issue. 

 ...and anyway, you don't weld steel bike frames, you braze them!

Cheers,

               W.

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2 hours ago, fastyacht said:

In "the new sciens of strong materials" J.E. Gordon used the Comet as an example of what should have been known from Griffith's work and otehr staete of the art knowledge. IT took the Comet and some other things to get it to sink in. (Liberty ships too--but for them it was the DBTT or ductiel to brittle transition temperature which is a characteristie weirdnessof BCC crystal structures (and to a far lesser extent HCP as well). FCC structures (aluminum, austenitic sstanklesss steel) are immune.

 

A book that should be on every engineer and manufacturers bookshelf. 

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9 hours ago, Zonker said:

Sheesh. It's a one off race boat. Nobody gives you a fatigue life because 

(a) its impractical to measure the actual loads in service for years and then apply to  the structure. "Mr. Rich Dude your keel has only 1 more ocean race allowed before we need to give you a new keel"

(b) most designers would have no idea how to even do the calcs. Best they can do is a damage and fatigue tolerant design.  Ferrari doesn't give you anything like if you buy a limited edition track car either. They don't say "well it's done 500 km on a track so time for new control arms".

 

so its not safe to go out on yacht with a welded keel as nobody knows when it will fall off?

( perhaps they should be sealed and pressurized, loss of pressure is the warning to get back to the dock)?

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5 hours ago, Boink said:

@fastyacht 

"DBTT or ductiel to brittle transition temperature which is a characteristie weirdnessof BCC crystal structures"

Is this phenomena the same that caught out the series of Iron Ore & Bulk carrier ships that were lost? c.30+ years ago?

I doubt it. Like the Derbyshrire? That was a hatch failure. There were over 300 bulk carrier sinkings durinkg that period iirc. Hatches are fundamentally flawed. The lip gets torn off from below it when you have a breaking wave impinging on the coaming.

The think with bukers is the cargo is dense and it also shifts. Troubble wit hcapital T. Kind like that croce song.

There's in my opinion a simple fix (thought of it in 90s) to keep hatch covers on:

 

 

flange for hatch.png

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6 hours ago, WGWarburton said:

I've always been given to understand that if a steel bicycle frame is done right it flexes within its elastic limit and fatigue is a non-issue. 

 ...and anyway, you don't weld steel bike frames, you braze them!

Cheers,

               W.

Even if done right, if you weight 100 kg you are gong to fatigue a traditional frame because the tubing is only available in a narrow set of thickness specs at the butts.

Both brazing and welding have HAZ issues. Silver solder versus brass was all the rage in the 70s because the former is at lower heat the idea being you can prevent excessive grain growth. The heat treated manganese molyb=denum by Reynolds (753) could only be silver soldered -- you had to submit test joint to reynolds to build with it!  Still, I fatitgued one.

Fatigue occurs in the elastic limit. That's part of the problem. Unit stress has ti be well below elastic to get to a steel fatigue limit. Aluminum doessnt have a fatigue limit 10^12 CYCLES or something basically is the same thing.

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9 minutes ago, fastyacht said:

Even if done right, if you weight 100 kg you are gong to fatigue a traditional frame because the tubing is only available in a narrow set of thickness specs at the butts.

 

So that's why my 50yr old lug jointed bike is still going strong, I have never weighed 100kg  :).

Out of interest, where did you find the fatigue cracks starting? I can do a proper check when I next look over the frame.

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4 minutes ago, fastyacht said:

Even if done right, if you weight 100 kg you are gong to fatigue a tradition al frame because the tubing is only available in a narrow set of thickness specs at the butts.

Both brazing and welding have HAZ issues. Silver solder versus brass was all the rage in the 70s because the former is at lower heat the idea being you can prevent excessive grain growth. The heat treated manganese molyb=denum by Reynolds (753) could only be silver soldered -- you had to submit test joint to reynolds to build with it!  Still, I fatitgued one.

Fatigue occurs in the elastic limit. That's part of the problem. Unit stress has ti be well below elastic to get to a steel fatigue limit. Aluminum doessnt hVE A FATIGUE LIMIT BUT 10^12 CYCLES or something basically is the same thing.

There's no such thing as a "traditional" aluminium frame, they didn't go beyond experimental until well into the 60s... :-). It's a crap material to make road bikes out of. There may be some benefits for off-road use but I'll leave that to others to argue, it's not my thing.

 What was it that failed on your Reynolds? I've heard of a few breaking, often because the thin walls are vulnerable to dings that weaken them, but not come across fatigue issues... was it the tube or the lug?

 I'm still riding the 531 touring frame my father bought when he was demobbed after WW2 (JohnMB, I'll see your 50 and raise you 10). It's lovely, though he was and I am both nearer 80Kg than 100...

Cheers,

              W.

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Just now, JohnMB said:

So that's why my 50yr old lug jointed bike is still going strong, I have never weighed 100kg  :).

Out of interest, where did you find the fatigue cracks starting? I can do a proper check when I next look over the frame.

donw tube HAZ (3 of those in the family)

botom bracket shell (twice)

chainstay haz at dropout. (twice on my bikes)

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11 minutes ago, WGWarburton said:

There's no such thing as a "traditional" aluminium frame, they didn't go beyond experimental until well into the 60s... :-). It's a crap material to make road bikes out of. There may be some benefits for off-road use but I'll leave that to others to argue, it's not my thing.

 What was it that failed on your Reynolds? I've heard of a few breaking, often because the thin walls are vulnerable to dings that weaken them, but not come across fatigue issues... was it the tube or the lug?

 I'm still riding the 531 touring frame my father bought when he was demobbed after WW2 (JohnMB, I'll see your 50 and raise you 10). It's lovely, though he was and I am both nearer 80Kg than 100...

Cheers,

              W.

That wasn't suppost to be Al that whas bad typing, Just traditional.

Traditional aluminum is a thing though. Dveloped in 60s sold as ALAN or as GUERCIOTTI. Epoxy glued tubes. First carbon bikes simply swapped out the Al tubes for carbon. "modern" Aluminum "invented" by Klein. Actually the BMX guys really figured it out too. At the same time.

Tubes. But in haz. point on a lug involved in most of them.

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15 minutes ago, WGWarburton said:

 I'm still riding the 531 touring frame my father bought when he was demobbed after WW2 (JohnMB, I'll see your 50 and raise you 10). It's lovely, though he was and I am both nearer 80Kg than 100...

Cheers,

              W.

Mine is also a touring frame, I suspect that the curvy forks on this type of frame  may also help as this should reduce the peak road loads on the frame.

Have we morphed into ancient bike anarchy, or are we still on materials science anarchy? (I have an average of 2 copies of both of Gordon's books on my bookshelf, one each of the old penguin edition which are not allowed to leave a radius of 50m from my desk, and loaner copies of the Princeton edition, which I don't care if I loose.)

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Yes to penguin!

Bicycles are perfect materials science teaching tools haha. Low Cost Home Fatigue Testing Machines. I've lost count of all the spokes and rims I've fatigued And axles.Perfect fatigue testing profile.

I weighted 170 to 190 lbs during the bulk of my fatigueing (what that in the 70 to 85 kg). But I was racing. High output and rough roads.Perfect fatigue testing profile.

I'm convinced that the frame tubesets at Columbus and Reynolds developed around 150 lb riders.

 

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On boats I've had fatigue failures too. Twice to plywood centerboards (505 and GP14). Rolling shear is a bitch. Every shroud I've borken (3 times!) has been corrosion + stress. The most noticable fatigue on boats is the softening of the hull in bending. That's a composite behavior and especially prevalent in chopped strand mat in polyester. You couldn't build a better limited bending life material.

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13 hours ago, Zonker said:

 

Well no. About 15 years or more ago I was doing it on an average CAD desktop PC. It's just faster now. Not even time to get coffee because multiple core processors mean you can do other stuff while the solver is running in the background. Actually now I get to delegate it to my clever peons who report back with nice reports with many coloured pictures that I can understand.

Zonker

     One of my favorite applications (actually a plug-in for Rhino3D) was called 'CoffeeBreak'. It was written by a brilliant coder who was still at the university at the time and made it freely available for Rhino3D v4 users. You just drag and dropped it onto a running instance of Rhino and the next time you started Rhino it was installed and even had cute little tool button showing a cup of steaming coffee to invoke the command. I just looked to see if it was still available and was surprised to see it so I downloaded and tried to see if it still worked in Rhino6 but sadly no. Then I opened RhinoV5 and it still works so I took a screengrab to share with you Zonk. 

 

image.png.002c59396feb29791b47aaf5e68803f2.png

 

    What the screengrab doesn't show are the scrolling windows and the everchanging 'FEA Solution Events' in the upper right hand window. The green bar graphs are constantly updating their status to show the "FEA Progress" but there is no 'remaining time' readout. That is because all the fancy calculations that seem to indicate a sophisticated Finite Element Analysis calculation that the poor desktop computer is feverishly grinding its poor CPU to death on is all just smoke and mirrors. The author wrote is as a joke or sorts so that one could start the busy little app and take as long a coffee break as one wished and if a boss or manager happened to walk by and see you not at your desk or just sitting idly watching the mesmerising data flow you could just casually mention how you needed a computer upgrade since these damned FEA runs were taking so long...

image

 

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1 hour ago, fastyacht said:

Yes to penguin!

Bicycles are perfect materials science teaching tools haha. Low Cost Home Fatigue Testing Machines. I've lost count of all the spokes and rims I've fatigued And axles.Perfect fatigue testing profile.

I weighted 170 to 190 lbs during the bulk of my fatigueing (what that in the 70 to 85 kg). But I was racing. High output and rough roads.Perfect fatigue testing profile.

I'm convinced that the frame tubesets at Columbus and Reynolds developed around 150 lb riders.

 

Not so sure about the low cost factor anymore. Just got back from my morning group ride with about 50 other idiots in their stretchy pyjamas. Stopped at one light and looked around at the array of Carbon, Steel and Alum bikes. Avg cost of say $3k each.  That's the cost of a used race yacht!

Of course it's all relative!

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11 hours ago, fastyacht said:

One advantage to composites is that, provided you have a baseline, it is possible to measure fatigue through deflection. Never heard it done on a keel though but on rotorblades yes

I proposed a way to do this, at least on production boats with a GRP keel stub. Bond a laser on the bottom of the stub shining up on the overhead. Put a sharpie mark there. Observe its excursion while beating (and put sharpie marks at the extreme). If this line of marks starts getting longer after awhile, sell the boat!

Long ago, composite racing sailplanes were sold with the natural frequency of the wings listed in the log book. Idea is you bounce the wing up and down and measure the natural frequency, if it slowed down you had a fatigue problem. Sometimes this was listed as a required measurement at annual inspection. It proved to be impractical, any change in mass due to modifications, repair, paint, etc. changed it. Also very sensitive to how the fuselage was supported. No longer done.

8 hours ago, WGWarburton said:

I've always been given to understand that if a steel bicycle frame is done right it flexes within its elastic limit and fatigue is a non-issue. 

Steel (at least in lower grades) is an almost unique material in that if cycled below a critical stress value (well below the yield BTW) it can be cycled indefinitely without fatigue failure. That is a very rare property in any material, and one of the reasons for its wide use. Aluminum for example will fatigue at very high cycles even at very small stress values. 

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34 minutes ago, Hitchhiker said:

Not so sure about the low cost factor anymore. Just got back from my morning group ride with about 50 other idiots in their stretchy pyjamas. Stopped at one light and looked around at the array of Carbon, Steel and Alum bikes. Avg cost of say $3k each.  That's the cost of a used race yacht!

Of course it's all relative!

You can get really nice used boats for a lot less than that. The problem is when you get one, you cant just hang it up in the garage out of the way, and other garage users start getting pissy when you fill up the space with old race boats :).

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21 minutes ago, DDW said:

I proposed a way to do this, at least on production boats with a GRP keel stub. Bond a laser on the bottom of the stub shining up on the overhead. Put a sharpie mark there. Observe its excursion while beating (and put sharpie marks at the extreme). If this line of marks starts getting longer after awhile, sell the boat!

 

I have video in my files of a C&C 101 underway in a very slight seaway.  I marked the floors with a sharpie on centerline and then video’d the keel studs arcing back and forth on either side of the centerline mark.

Another boat I surveyed, a SC37, the previous crew had drawn marks on centerline of the bulkhead and keel trunk/ table module so they could keep track of how far it moved.

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1 hour ago, Hitchhiker said:

crew had drawn marks on centerline of the bulkhead and keel trunk/ table module so they could keep track of how far it moved.

Heh.  Years ago I did a baja race on one of the early Macgregor-65s (yeah, I know, don't hate).

The boat was so bendy that if you sat in the companionway and looked below, you could watch the hull torque as the stern lifted on a wave, and the bow (eventually) came back into alignment.

I remember thinking at the time I wished I'd had a video camera.  It was sort of mesmerizing (and a little terrifying) to watch the structures flex, wave after wave.

My understanding is they added a whole bunch of stringers in later hulls.  Don't know, don't care, I never set foot on one after that.

 

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There was a big racing extremely light catamaran (FURY a 60' Lindenberg design) that got put out to pasture as a cattlemaran down in the Islands that was so flexible you could see the deck hatches saw back and forth on the edges opposite the hinges. As the monocoque hulls twisted from the sailing loads even in light winds I wondered how the structure could hang together. I used my fingers to gauge the displacement of the hatch center relative to the hatch coaming and it was maybe a half inch or more.  I saw that the hatch was not dogged and pointed that out to the skipper and offered to go below and dog the hatches and he just said not to bother because that would just break the hatch dogs...

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4 hours ago, Rasputin22 said:

Zonker

     One of my favorite applications (actually a plug-in for Rhino3D) was called 'CoffeeBreak'. It was written by a brilliant coder who was still at the university at the time and made it freely available for Rhino3D v4 users. You just drag and dropped it onto a running instance of Rhino and the next time you started Rhino it was installed and even had cute little tool button showing a cup of steaming coffee to invoke the command. I just looked to see if it was still available and was surprised to see it so I downloaded and tried to see if it still worked in Rhino6 but sadly no. Then I opened RhinoV5 and it still works so I took a screengrab to share with you Zonk. 

 

image.png.002c59396feb29791b47aaf5e68803f2.png

 

    What the screengrab doesn't show are the scrolling windows and the everchanging 'FEA Solution Events' in the upper right hand window. The green bar graphs are constantly updating their status to show the "FEA Progress" but there is no 'remaining time' readout. That is because all the fancy calculations that seem to indicate a sophisticated Finite Element Analysis calculation that the poor desktop computer is feverishly grinding its poor CPU to death on is all just smoke and mirrors. The author wrote is as a joke or sorts so that one could start the busy little app and take as long a coffee break as one wished and if a boss or manager happened to walk by and see you not at your desk or just sitting idly watching the mesmerising data flow you could just casually mention how you needed a computer upgrade since these damned FEA runs were taking so long...

image

 

Very much like the "Boss Key" in early pc games that would allow you to instantly pull up a spreadsheet or other work like activity if your boss rounded the corner mid game. Now you can just switch windows.

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I can't find his quote but Moon Duster pointed me to the DNV-GL rules for Yachts which do indeed have fatigue calc requirements for yachts. It's quite detailed and I skimmed but it looks very useful. It took some finding but it it's here. These rules only apply to Yachts of >24m so it is "big sailing yacht" oriented and maybe some loads should be taken with a grain of salt (bigger boats more likely to hit bad weather than smaller 40' which may hide or not attempt too many long ocean races?) but it's something at least and good guidance for fabricated keels. It's here:

Part 3 Hull Chapter 7 Rudder, foundations and appendages, which sends you to:   Part 3 Hull Chapter 4 Metallic hull girder strength and local scantlings -Appendix D

One thing I found interesting "A default value of this design life is 5 years with a fraction of 15% spend at sea, or the pertinent mileage"

"The characteristic cycling regime is intended to provide coverage of min. 60000 miles (depending on boat size) under random sea conditions. The dynamic loadings cumulating to this spectrum are derived from wave encounters resulting in amplified gravitational effects."

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1 hour ago, KC375 said:

Very much like the "Boss Key" in early pc games that would allow you to instantly pull up a spreadsheet or other work like activity if your boss rounded the corner mid game. Now you can just switch windows.

When I worked for a short time in Big Corporate in the late 90s I quickly learned what the sound of "alt tab" was. You'd turn a corner and just before you'd see a screen you'd hear it. The little window someone had open would just disappeared. When I found myself in a pretty big place again in the later aughts I immediately recognized the sound but this time it was myspace windows that were disappearing.

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5 hours ago, Hitchhiker said:

Not so sure about the low cost factor anymore. Just got back from my morning group ride with about 50 other idiots in their stretchy pyjamas. Stopped at one light and looked around at the array of Carbon, Steel and Alum bikes. Avg cost of say $3k each.  That's the cost of a used race yacht!

Of course it's all relative!

Things like this not getting cheaper.

There are many US firms in furniture, electronics, apparel, tires and vacuum cleaners etc who have Chinese supply lines and are struggling because of the trade war between China & US that started 18 months ago. One alternative for them is to find new supply chains in places like Taiwan, Thailand, Vietnam and other Asian countries. However that not often easy.

Seems bicycles are also on that Trump hit list so increases their cost and or impacts upon their supply.

The US/China Phase 1 Trade Deal gets signed today. It will hold off increasing tariffs Trump imposed on bicycles from China. But the 25% tariff on bikes and a host of other products will remain in place to give the U.S. leverage in further talks for Phase 2.

U.S. bike firms face uphill slog to replace Chinese supply chains

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14 minutes ago, fastyacht said:

You'd turn a corner and just before you'd see a screen you'd hear it. The little window someone had open would just disappeared.

Amateurs. 

When I worked for Big Corporate (actually, Big Defense Contractor), my team chipped in to get one of those infrared-beam door-chimes from Radio Shack... you know, the thing that makes a bell go off when someone walks into a small shop?

Wired it to a small light on top of a shared whiteboard, instead of a chime.  Everyone on my team got fair warning that "the boss" was coming down the hall, long before the contents of our screens were visible.

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On 1/14/2020 at 12:50 AM, Miffy said:

The Pogo’s keel and mounting method is one of the most robust out there. 

 

Why thought? Not doubting it, genuinely interested. What makes their breed of lift up keel more robust than welded, wanky matrix configurations, boring old keel bolts etc?

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The large pin that the keel rotates on is mounted horizontally and a hydraulic ram keeps the keep in position. The keel is manufactured with quality assurance of a proper factory and the end installer isn't really being asked to provide some end user installation that can make or break the boat. The yard/design is willing to make the accomodation to the interior of the boat with a rigid supporting structure around the ram/keel assembly - which has more leveraged stiffness because it sits so high in the boat. 

There are bad bolt designs that work on paper but in the real world w/ boat launch services and environmental variables - are just unnecessarily risky. For example, I'd never accept a boat design where the keel bolts are on the same plane and don't mount into a slot in the hull - yet you still find production and custom boats where the keel is supposed to stay rigid without introducing cycling fatigue on the bolts while being compressed against the composite hull in changing temperature & loads & varying service/launching parameters. 

Unless you're managing an America's Cup campaign or some high quality yard services - IMO the designer has to assume the boat will be launched and maintained by monkeys. 

 

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18 hours ago, Zonker said:

One thing I found interesting "A default value of this design life is 5 years with a fraction of 15% spend at sea, or the pertinent mileage"

So, as a direct consequence, the rules preclude racing a boat older than 5 years? Nothing else is logically consistent.....

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On 1/7/2020 at 12:27 AM, Jason Ker said:

Most of the original mass was there so we could tick the 'Solid Iron' box on the IRC form, back when that was important.

Welds in tension are risky, you certainly wouldn't get an airplane certified that had its wings held on that way...

In the construction industry we use weld in tension all the time (https://www.newsteelconstruction.com/wp/wp-content/uploads/TechPaper/NSCTechJune16.pdf). For instance we weld end plates to an I beam with moments in it. There are quite a few out there with my name on it. I would be curious to know why it is unacceptable for boats and planes.

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59 minutes ago, Zonker said:

Cyclic loads I'd say. Direct tension is fine. But on boats the load cycles are real guesses.

Makes sense. It must be really hard to avoid tension everywhere.

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5 hours ago, Panoramix said:

In the construction industry we use weld in tension all the time (https://www.newsteelconstruction.com/wp/wp-content/uploads/TechPaper/NSCTechJune16.pdf). For instance we weld end plates to an I beam with moments in it. There are quite a few out there with my name on it. I would be curious to know why it is unacceptable for boats and planes.

Yep, high numbers of fatigue cycles - even just bobbing around in the dock, plus a highly corrosive environment where minute surface imperfections can easily initiate stress cracks.  Carbon fibre and mixed metals are also a pretty interesting galvanic proposition as I understand it. 

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11 minutes ago, DickDastardly said:

Yep, high numbers of fatigue cycles - even just bobbing around in the dock, plus a highly corrosive environment where minute surface imperfections can easily initiate stress cracks.  Carbon fibre and mixed metals are also a pretty interesting galvanic proposition as I understand it. 

Carbon is so noble that only platinum and titanium behave in contact wth it. Even on my dinghy which is dry sailed, the stanless bits that are in contact woth carbon (tiller bolt etc) are RUSTY like ordinary steel. Thats because it loses passivation.

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So, as a direct consequence, the rules preclude racing a boat older than 5 years? Nothing else is logically consistent.....

Yeah, no. What's logically consistent is that for highly engineered structures with relatively short fatigue life, the owner track actual usage or model fatigue life with data that's more accurate then the GL rule-of-thumb. Let's be clear, these are not mom-and-pop cruising boats, these are aggressive offshore race boats built on large budgets with aggressive aspirations. Tracking hours is the key to maintenance and replacement schedules. I'd think you'd understand that from the things you fly, which I'm sure are maintained by hours-flown, not years owned.

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Hours don't mean much unless you also tracking sea state, speeds, etc etc.

What we really need is to strain gauge lots of parts of keel with lots of real time data collection over 5 years of ocean racing! <sarcasm>

That would be very, very costly and impractical for just about any top end racing program. I do know some Ocean 60s were strain gauged INSIDE the hull to help understand slamming loads when forward bottom structures kept failing. But immersed strain gauges in ocean environments have a poor track record for extended life. Not to mention all the drag from the little wires taped to the exterior of the keel wouldn't be popular!

As a realistic minimum, removing bottom paint and any other coating annually near the kel root for NDT testing is probably a good idea for any high end race program.

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2 hours ago, Moonduster said:

So, as a direct consequence, the rules preclude racing a boat older than 5 years? Nothing else is logically consistent.....

Yeah, no. What's logically consistent is that for highly engineered structures with relatively short fatigue life, the owner track actual usage or model fatigue life with data that's more accurate then the GL rule-of-thumb. Let's be clear, these are not mom-and-pop cruising boats, these are aggressive offshore race boats built on large budgets with aggressive aspirations. Tracking hours is the key to maintenance and replacement schedules. I'd think you'd understand that from the things you fly, which I'm sure are maintained by hours-flown, not years owned.

If it is spec'd that way, then why not limit life that way? It is logically inconsistent. If these structures are going to be as tightly engineered as aircraft (and the consequences nearly as severe) then keeping logbooks of use and requiring inspection or refit at the intervals required of the design is appropriate. These aren't, as you say, mom and pop cruising boats. 

One problem is that once discarded by the high buck race program when past their best-by-date, they often end up in the hands of just above mom and pop programs. Perhaps as this one did here (second hand, lowest bidder keel design/manufacture retrofit).

(And by the way, most GA aircraft in the US are inspected annually, not by hours flown....commercial are hours flown.) 

 

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19 minutes ago, Moonduster said:

No, one doesn't need to track sea state. Averages work. One needs to track days, have a reasonable safety margin and use qualified NDT people and techniques to track performance to predictions.

keels should have PBO tethers like F1 uprights do

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7 minutes ago, Sailabout said:

keels should have PBO tethers like F1 uprights do

That's an interesting idea but how would you set it(them?) up to be useful? There's no gain in simply hanging on to the keel (unless for later repair or analysis.. need to survive & recover first!), as demonstrated by HB cutting theirs away after the attachment failure. You could imagine it could be a liability, as with a broken rig, still attached by rigging, banging holes in your hull...

 I'm not dumping on the idea, just not seeing immediately how to make use of it... what do you have in mind?

Cheers,

              W.

 

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One idea from car racing that might be applicable to a hollow fin fabrication: fill it with nitrogen to 20 psi. Monitor the pressure. If it drops, you've got a problem. Porsche did this in the 917 aluminum tube race car frame, as they knew they would fatigue and crack. I doubt they invented the idea.

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That big Helo of the type that was used for the Iranian hostage rescue attempt (CH-53) had the composite blades pressurised for some of the same reasons. They gas they filled the hollow blades with was doped with radon or tritium or something mildly radioactive and instead on monitoring the pressure they had small geiger counters on the hub that would detect any leaking radioactive gas from small arms fire strikes or other mechanical issues. Apparently that was more effective that trying to plumb all pressure guages steam punk style through all 5 (or 6?) blades through an already complicated hub which gimbaled every which way. Today they would probably just use a sensor that would talk to the flight system wirelessly like via Bluetooth but the system seems to work pretty well. I guess if your rotor just got shot off you wouldn't be worried about a bit of radiation...

CH-53Ds_landing.jpg

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On 1/13/2020 at 1:27 PM, Miffy said:


Not everyone has the production engineering support from TSMC to do the manufacturing ;)

We use those guys for the simple CMOS stuff, which they are very good at... 

 The trade secret stuff we do inside... 

 

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On 1/13/2020 at 2:12 PM, JohnMB said:

Impressive, you must be right at the limit of meaninglessness for a continuum model. I'm guessing those small elements must be only 5-10 atoms across.

On that order; where the dielectric thickness control becomes better due to quantization of the number of molecules in the stack and you can count integer electrons on the memory nodes. This is higher voltage. 

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I did think of the Porsche 917 solution but because cracks that you care about probably start on the outside of the fin, by the time it reaches the interior and starts leaking it might be too late.

And then nobody reads the keel pressure gauge before or during the race anyway.

 

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20 minutes ago, Zonker said:

I did think of the Porsche 917 solution but because cracks that you care about probably start on the outside of the fin, by the time it reaches the interior and starts leaking it might be too late.

And then nobody reads the keel pressure gauge before or during the race anyway.

  

So you make a popup on the MFD much as in your automobile that warns you of tire pressure changes.... 

 

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If you want a quick and easy visual indicator of fatigue early detection - just setup a pair of aluminium spokes completely encapsulated in epoxy and have them tensioned alongside the keel attachment surfaces connecting the keel & the hull. If there's more cycling than anticipated they'll break in short order like spokes in a wheel - when one breaks, you know something is off and the entire wheel needs to be retensioned and inspected. Aluminium spokes will fatigue to failure long before steel or composite structure around the hull. 

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On 1/10/2020 at 4:44 AM, JL92S said:

Besides, said owner of Concise isn’t exactly the most savoury of characters and what comes out of his gob often lands him in trouble and pisses people off

JL, the owner has been one of my closest friends for half a century, and you are the first person I have ever heard say something like that about him. Interesting. Maybe you are confusing him for someone else entirely. The opinion of those who actually know him is pretty much exactly the opposite, and that includes an enormous number of people. He is gregarious and charitable on a global scale.

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3 minutes ago, carcrash said:

JL, the owner has been one of my closest friends for half a century, and you are the first person I have ever heard say something like that about him. Interesting. Maybe you are confusing him for someone else entirely. The opinion of those who actually know him is pretty much exactly the opposite, and that includes an enormous number of people. He is gregarious and charitable on a global scale.

TL  has never been part of the Solent 'in crowd'... I think that's entirely healthy

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1 hour ago, LionessRacing said:

So you make a popup on the MFD much as in your automobile that warns you of tire pressure changes...

The difference between you and me. I read a pressure gauge and have every confidence it's reading keel pressure.

You hope that the electronics transducer in the wet bilge is working and taking to the MFD :-) 

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15 minutes ago, Zonker said:

The difference between you and me. I read a pressure gauge and have every confidence it's reading keel pressure.

You hope that the electronics transducer in the wet bilge is working and taking to the MFD :-) 

Not quite, I hope the that automagic system is going to prompt me to a change in the middle of the drive, not something I would pick up on a walk around, and before I have a deterioration of control that I would notice in the steering. 

Similarly while most people know that they should check the oil level in sump and transmission, and the water level in their batteries, how many actually do it? 

An oil pressure gauge backed up by a buzzer/horn and other alarms that notify you to read a gauge have their place in that they don't forget, though they may fail. 

When it's mission critical, I'm my likely to be setting up a control chart and using SPC software to look at trends to catch problems before excursions. and that's really hard to do with a manual measurement that you don't plot... 

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2 hours ago, Zonker said:

I did think of the Porsche 917 solution but because cracks that you care about probably start on the outside of the fin, by the time it reaches the interior and starts leaking it might be too late.

And then nobody reads the keel pressure gauge before or during the race anyway.

 

It only works well if the crack propagate slowly. I'd guess the cracks actually start on the inside, not the outside. Without extraordinary measures, the inside is the backside of the weld, cannot be filleted at all, and is less likely to be shielded with inert gas (unless backflushed, and even then). It is uninspectable visually. 

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Just now, DDW said:

It only works well if the crack propagate slowly. I'd guess the cracks actually start on the inside, not the outside. Without extraordinary measures, the inside is the backside of the weld, cannot be filleted at all, and is less likely to be shielded with inert gas (unless backflushed, and even then). It is uninspectable visually. 

To accomplish the weld, you need a suitable elding procedure. The weld would then be radiologically inspected. There are plenty of inaccesible back-welds that are critically important and QC'ed to be sure they are OK.

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1 hour ago, fastyacht said:

To accomplish the weld, you need a suitable elding procedure. The weld would then be radiologically inspected. There are plenty of inaccesible back-welds that are critically important and QC'ed to be sure they are OK.

Getting a "suitable Welding procedure" is the key, and being able to validate the results, is an aspect of a third party certification that would make sense. 

The clean process plumbing industry has figured out how to machine electro-weld 316L stainless with 5 9's Argon, but that's unlikely to be found in a boat yard, though you might in a shipyard... 

 

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2 minutes ago, LionessRacing said:

Getting a "suitable Welding procedure" is the key, and being able to validate the results, is an aspect of a third party certification that would make sense. 

The clean process plumbing industry has figured out how to machine electro-weld 316L stainless with 5 9's Argon, but that's unlikely to be found in a boat yard, though you might in a shipyard... 

 

The "excuse" (not you making it) that a "boatyard doesn't have the XYZ" is just crap. If you are going to Run with the Big Dogs, you either Get It Done or you Get Out he Way.

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4 minutes ago, fastyacht said:

The "excuse" (not you making it) that a "boatyard doesn't have the XYZ" is just crap. If you are going to Run with the Big Dogs, you either Get It Done or you Get Out he Way.

Your basic race boat fabricator will do a hell of a lot less critical welding than Bath Iron Works... 

and who ever they would hire to do the welding will do a few keels in a year max...

I could tack weld well enough to get my work piece to the fabricator to burn, with a multi-thousand dollar multi kilowatt welder with gas run a by a guy who welds 6 hrs a day

 

 

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2 minutes ago, LionessRacing said:

Your basic race boat fabricator will do a hell of a lot less critical welding than Bath Iron Works... 

and who ever they would hire to do the welding will do a few keels in a year max...

I could tack weld well enough to get my work piece to the fabricator to burn, with a multi-thousand dollar multi kilowatt welder with gas run a by a guy who welds 6 hrs a day

 

 

There are specialist high technology welding firms scattered all over Connecticut and new England.

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6 minutes ago, LionessRacing said:

Your basic race boat fabricator will do a hell of a lot less critical welding than Bath Iron Works... 

and who ever they would hire to do the welding will do a few keels in a year max...

I could tack weld well enough to get my work piece to the fabricator to burn, with a multi-thousand dollar multi kilowatt welder with gas run a by a guy who welds 6 hrs a day

 

 

If you are going to have a keel supplied in Australia/New Zealand the only go to place is Kawerau Engineering in New Zealand as have all the systems and experienced/qualified welders in place.

https://www.kaweraueng.co.nz/page/keels.html

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11 minutes ago, fastyacht said:

There are specialist high technology welding firms scattered all over Connecticut and new England.

No doubt, and elsewhere as well. 

And then you get into the questions of whether they are familiar with the alloys being used etc. Not saying it can't be done successfully, just that as a point of high stress or as Moonduster says "highly engineered" it behooves the use of not just highly talented staff, but high experience in the particular type of weld, materials preheating, and application. 

Being able to preheat a large/massive/delicate dimension-ed high alloy structure may be beyond the experience of many. 

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14 minutes ago, LionessRacing said:

No doubt, and elsewhere as well. 

And then you get into the questions of whether they are familiar with the alloys being used etc. Not saying it can't be done successfully, just that as a point of high stress or as Moonduster says "highly engineered" it behooves the use of not just highly talented staff, but high experience in the particular type of weld, materials preheating, and application. 

Being able to preheat a large/massive/delicate dimension-ed high alloy structure may be beyond the experience of many. 

No Doubt. But so is building a 50 foot carbon pre-preg hull out of 250 degree cure prepreg. That's the point.

So here's the thing. In the US, there are NO RULES unless you are over 24 meters and a commerical yacht--then you (until last year) couldn't exist in the US--you had to be foreign flagged and that required MCA or other flag and some minimum scantlings requirements etc....

In the US, for pleasure boats, it is Wild West. In EU it is "supposed" to meet "standards" from EN but while there are pretty detailed parts of that set of rules, it isn't a comprehensive engineering rue set. It is generally prescriptive. Some of it is quite good though.

To do things right takes skills and expertise which is not a problem--it just costs money and time.

That some will chose to do things dangerously is the way of the world.

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1 hour ago, Chucky said:

Kawerau Engineering...

Reads like they do things right - but then I see the 52 HVS 316 (image 4 in fixed keel page) and figure that's the sort of design Jason Ker didn't like with side plates welded to the base plate.

Image 5 (Yendys) has what looks like a single row of bolts on centreline. Why when you have a big mounting flange??!?!

Not blaming them, they just build what the designer draws...

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7 hours ago, fastyacht said:

To accomplish the weld, you need a suitable elding procedure. The weld would then be radiologically inspected. There are plenty of inaccesible back-welds that are critically important and QC'ed to be sure they are OK.

Didn't say they wouldn't be "OK" according to some QC procedure. Just guessed that is where the crack will start, because even if "OK" it isn't going to be as good as the one you can get to and see on the front side. On a typical CP type weld the back side looks pretty ugly, in xray or in person. 

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On 1/11/2020 at 2:38 AM, Fiji Bitter said:

 

Heard that story too, I am sure it was an Italian boat, possibly Giorgio Falck's Rollygo in the 81/82 race. Can't find it on the web though.

 

Best Oh Fock I know of was when the designer came to inspect a steel build, and couldn't work out what happened to his interior plan. Until the builder admitted they accidentally put two frames extra in, adding 2ft to it, and suggested to tell the owner that he was getting a bigger boat for the same money. When that boat later won the Bermuda Race they ordered another one, stressing that it had to have the extra frames too!

 

Tales I heard, it was one of the Scandinavian boats, there were quite a few back then.

Also heard this, or similar about a composite build quite a few years ago........no names mentioned.:ph34r::P

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On 1/11/2020 at 2:53 AM, jack_sparrow said:

That was probably the forerunner of modern production boat design and construction techniques. These days you have to take the deck off to replace the cooktop/oven. Replacement engine solution is buy their latest new boat model. 

There's a certain old maxi boat that has had a chunk of cockpit floor cut out more often than you can count, we finally turned it into a proper hatch arrangement. 

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  • 4 weeks later...

This article courtesy of  Sailworld dated 13th Feb, 2020. I would imagine Jason Ker, keel designer, keel builder, boat owner and  the insurance company would be interested in the outcome of this report?

Australian Sailing has determined to conduct a review into the LCE Showtime incident and provide a report on the facts and learnings of the incident.

After completing the CYCA's 2019 Sydney Hobart Yacht Race, race entrant LCE Showtime was being delivered back to Sydney when on 5 January 2020 at 0230 hours the keel failed, and the crew activated its emergency beacon. The NSW police service responded to the incident and all crew were rescued.

Australian Sailing has determined to conduct a review to provide a report on the factual happenings in respect of the incident. The National Safety Committee has appointed Tim Cox (chair), Chris Zonca and Frank Walker to conduct the Review.

Of particular interest to the review are the processes relating to the original design and modifications to the keel, groundings or impacts, administrative procedures and documentation, actions undertaken by the crew at the time of the incident, and the application of the Australian Sailing Sea Safety Survival Course content to the experiences of the crew of LCE Showtime.

Any interested party may make written submissions to the review by emailing technical@sailing.org.au. Parties wishing to be interviewed by the panel should also contact Australian Sailing at the same email.

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And the point of this is exactly

the witnesses are not compellable and the decision makers have no privileges 

and they have no physical evidence

so why would anyone talk to them

unless AS are now saying failure to co operate is rrs 69 territory

and no doubt owners might be saying  to thier contractors where is the duty to co operate that in your Agreement with me

no point with an enquiry if witnesses are not compellable 

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6 hours ago, lydia said:

And like any inquiry and I have done a few , what the the terms of reference

 

Terms of Reference can be found here:

Quote
Quote

Terms of Reference
The Review will examine all the circumstances pertaining to the loss of LCE Showtime and rescue of its crew and in particular:

(a)The Plan Review process relating to the original design and modifications to the keel.

(b)Prior groundings or impacts and subsequent keel inspection methods.

(c)Relevant  administrative  procedures  and  race  management  including boat documentation and organisation.

(d)The safety precautions, procedures and actions undertaken by the crew at the time of the incident.

(e)The application of the Australian Sailing Sea Safety Survival Course content to the experiences of the crew of LCE Showtime.
    If thought fit, the Review will make recommendations as to:
    (a)World Sailing’s Plan Review processes
    (b)Keel inspection procedures and practices(c)Australian Sailing’s Special Regulations

(d)Liferaft stowage(e)Race documents, race administration documentation and procedures(f)Onboard emergency management procedures; and(g)Any other matters relating to the conduct of the race as the Review considers appropriate.

 

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