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Harry Manko

J80 Loses Keel

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Going back to the early J24 sump problems Jboats has usually come up with a fix of some type that is a least a starting point of repairing a boat

 

Structural Repair Considerations

For J/80s, the owner and a certified SAMS (www.marinesurvey.org) surveyor or composites expert should (1) determine the extent of cracking, distortion, wetness or delamination and (2) if there is any evidence discovered in step #1 that indicates a potential problem, the surveyor should then conduct destructive or non-destructive testing and, depending on the results of the test, recommend a repair procedure that is carried out by a qualified repair facility.

 

There response to J80 owners to go out get a survey and then figure out on your own a way to beef up OR repair the issue is a poor answer

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It's ridiculous. I like the J family, but it's safe to say that there are some major quality control issues at TPI. Does anyone know of Beneteaus or other production boats that have had as many catastrophic failures? How about Moore 24's? Have any of those keels fallen off in over 30 years? They have certainly been raced hard enough. As for the "it's a race boat" argument, the J/80 is so far from an all out racing boat that it's not even worth joking about. It's a moderate performance production one design. The keels should stay on. My guess (me no engineer) is that if it was a design issue it would have shown up earlier in the life of the J/80 class as it did with the Melges 30'. The randomness is the scary part about the J/boat keel drama.

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It's ridiculous. I like the J family, but it's safe to say that there are some major quality control issues at TPI. Does anyone know of Beneteaus or other production boats that have had as many catastrophic failures? How about Moore 24's? Have any of those keels fallen off in over 30 years? They have certainly been raced hard enough. As for the "it's a race boat" argument, the J/80 is so far from an all out racing boat that it's not even worth joking about. It's a moderate performance production one design. The keels should stay on. My guess (me no engineer) is that if it was a design issue it would have shown up earlier in the life of the J/80 class as it did with the Melges 30'. The randomness is the scary part about the J/boat keel drama.

 

how many j boat catastrophic failures have their been? I count two - the two j80s. The j109 had keel issues, but I believe they were all resolved - by J - before any catastrophically failed. There was a J120 or J133 or something too I think that had to be repaired. I'm not saying you're wrong, but can you please provide your citation?

 

FWIW, I've had two boats built by TPI/Pearson Composites, and the keels haven't fallen of either one. (Anecdotal evidence is the worst way to support an argument, regardless of the argument's merits).

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Going back to the early J24 sump problems Jboats has usually come up with a fix of some type that is a least a starting point of repairing a boat

 

Structural Repair Considerations

For J/80s, the owner and a certified SAMS (www.marinesurvey.org) surveyor or composites expert should (1) determine the extent of cracking, distortion, wetness or delamination and (2) if there is any evidence discovered in step #1 that indicates a potential problem, the surveyor should then conduct destructive or non-destructive testing and, depending on the results of the test, recommend a repair procedure that is carried out by a qualified repair facility.

 

There response to J80 owners to go out get a survey and then figure out on your own a way to beef up OR repair the issue is a poor answer

 

What sump problems are you referring to? I thought it was the vermiculite that was the problem not the actual sump?

 

Just did a verm job on my nephews 1979 J24, just curious.

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Structural Repair Considerations

For J/80s, the owner and a certified SAMS (www.marinesurvey.org) surveyor or composites expert should (1) determine the extent of cracking, distortion, wetness or delamination and (2) if there is any evidence discovered in step #1 that indicates a potential problem, the surveyor should then conduct destructive or non-destructive testing and, depending on the results of the test, recommend a repair procedure that is carried out by a qualified repair facility.

 

There response to J80 owners to go out get a survey and then figure out on your own a way to beef up OR repair the issue is a poor answer

 

Was this a statement issued by J-boats?

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What sump problems are you referring to? I thought it was the vermiculite that was the problem not the actual sump?

 

Just did a verm job on my nephews 1979 J24, just curious.

There has been a quite scholarly study done on the J24 (strain gages sailing, F.E. analysis, etc.) which concluded that in several areas the fiberglass laminate was being stressed near, or beyond, reasonable fatigue limits. They cut sections out of older examples and tested the laminate to destruction to determine what the fatigue limits were.

 

Not to pick on J boats necessarily, but I have seen several J-boat keels prior to attachment to the hull, which gives you an opportunity to appreciate what is being used to accomplish the attachment. From these observations, I conclude that the real surprise is not how many have fallen off, but rather how many have stayed on.

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What sump problems are you referring to? I thought it was the vermiculite that was the problem not the actual sump?

 

Just did a verm job on my nephews 1979 J24, just curious.

There has been a quite scholarly study done on the J24 (strain gages sailing, F.E. analysis, etc.) which concluded that in several areas the fiberglass laminate was being stressed near, or beyond, reasonable fatigue limits. They cut sections out of older examples and tested the laminate to destruction to determine what the fatigue limits were.

 

Not to pick on J boats necessarily, but I have seen several J-boat keels prior to attachment to the hull, which gives you an opportunity to appreciate what is being used to accomplish the attachment. From these observations, I conclude that the real surprise is not how many have fallen off, but rather how many have stayed on.

To strike a contrarian view here. ...and yet the keels have stayed on so either your observation is not based in engineering science or something else is at play here. I don't know if you have an engineering background, I just pointing out that statistically the numbers are on JBoat's side.

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It's ridiculous. I like the J family, but it's safe to say that there are some major quality control issues at TPI. Does anyone know of Beneteaus or other production boats that have had as many catastrophic failures? How about Moore 24's? Have any of those keels fallen off in over 30 years? They have certainly been raced hard enough. As for the "it's a race boat" argument, the J/80 is so far from an all out racing boat that it's not even worth joking about. It's a moderate performance production one design. The keels should stay on. My guess (me no engineer) is that if it was a design issue it would have shown up earlier in the life of the J/80 class as it did with the Melges 30'. The randomness is the scary part about the J/boat keel drama.

 

How many J/80's are there now - 1,000? Both of the TWO that lost their keels were allowed to bounce around on rocks earlier in their lives, setting up the later failures. Frankly I don't know why J Boats hasn't come out and stated this publicly - I suspect the owners' insurance companies had something to do with it.

 

A couple of guys sailed a J/80 across the Atlantic. I wouldn't rule out doing a TransPac in one, but for the cabin/cockpit layout and the race being mostly DDW.

 

J/World has a whole fleet of early ones (most 1993-94) and beats the crap out of them.

 

 

This is an old thread - why are we rehashing it all again?

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It's ridiculous. I like the J family, but it's safe to say that there are some major quality control issues at TPI. Does anyone know of Beneteaus or other production boats that have had as many catastrophic failures? How about Moore 24's? Have any of those keels fallen off in over 30 years? They have certainly been raced hard enough. As for the "it's a race boat" argument, the J/80 is so far from an all out racing boat that it's not even worth joking about. It's a moderate performance production one design. The keels should stay on. My guess (me no engineer) is that if it was a design issue it would have shown up earlier in the life of the J/80 class as it did with the Melges 30'. The randomness is the scary part about the J/boat keel drama.

 

How many J/80's are there now - 1,000? Both of the TWO that lost their keels were allowed to bounce around on rocks earlier in their lives, setting up the later failures. Frankly I don't know why J Boats hasn't come out and stated this publicly - I suspect the owners' insurance companies had something to do with it.

 

A couple of guys sailed a J/80 across the Atlantic. I wouldn't rule out doing a TransPac in one, but for the cabin/cockpit layout and the race being mostly DDW.

 

J/World has a whole fleet of early ones (most 1993-94) and beats the crap out of them.

 

 

This is an old thread - why are we rehashing it all again?

What is the basis/proof of your statement about the history of the two boats with failed keels (one of which used to belong to me)? There is no merit to it. The sumps are simply too thin! Several owners of double digit hulls have had their sumps reinforced.

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What sump problems are you referring to? I thought it was the vermiculite that was the problem not the actual sump?

 

Just did a verm job on my nephews 1979 J24, just curious.

There has been a quite scholarly study done on the J24 (strain gages sailing, F.E. analysis, etc.) which concluded that in several areas the fiberglass laminate was being stressed near, or beyond, reasonable fatigue limits. They cut sections out of older examples and tested the laminate to destruction to determine what the fatigue limits were.

 

Not to pick on J boats necessarily, but I have seen several J-boat keels prior to attachment to the hull, which gives you an opportunity to appreciate what is being used to accomplish the attachment. From these observations, I conclude that the real surprise is not how many have fallen off, but rather how many have stayed on.

DDW

 

Can you point me to the J24 stuff I'd like to read that.

I always wondered about the 90 degree corner where the sump meets the hull...thats not stong in FRP?

 

Thanks

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To strike a contrarian view here. ...and yet the keels have stayed on so either your observation is not based in engineering science or something else is at play here. I don't know if you have an engineering background, I just pointing out that statistically the numbers are on JBoat's side.

Yeah...5200 is amazing stuff, huh? I do have an engineering background and I attribute the relative lack of failures due to most boats not getting used that much, or that hard. I will grant you that 1/500 is not a high failure rate in a hand built product, if it were a winch or a deck cleat or even the mast this might be acceptable. However a keelboat dropping the keel is more like the wings falling off an airplane: it is very likely to lead to death, and in this instance no failures are acceptable, in my opinion. They certainly weren't necessary in most of the recent cases, and could have been reliably prevented by proper structural analysis and/or proper manufacture. I don't give J-boats a pass on their stated attitude that (to paraphrase) 'these boats are getting old and some of them are likely to be coming apart'.

 

Can you point me to the J24 stuff I'd like to read that.

I always wondered about the 90 degree corner where the sump meets the hull...thats not stong in FRP?

 

Thanks

Linky

 

Note that in this paper they were primarily concerned with slamming loads in the forward sections, not keel loads.

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I know that with old race powerboats everyone is warned dont race old boats as they have been seriously weekened by slamming loads.

Several have failed thats why they say it.

There is no test that I know of to determine if the laminates are failing ( cut a piece of hull out) so when they get older as you say they are no longer at the designed strength and being a non homogonous material there will be plenty of Friday layups and or Friday in the chemical factory as well.

 

I wonder how they will test the new Dreamliner to determine its still as built?

Cheers

Sailabout

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I wonder how they will test the new Dreamliner to determine its still as built?

Cheers

Sailabout

I have to believe that the Dreamliner was engineered to a higher standard than a J80. At least I hope so.

 

There have been certified fiberglass aircraft built since around 1970 or so. Initially the thinking was that you could measure the stiffness of the structure (which you can do non-destructively) as in tests it tracks the reduction in ultimate strength well. For example my sailplane built in 1999 came with a figure for the natural frequency of the wing: you bounce it up and down and time the period. If this changes over time (gets longer) you know that it has weakened some amount. This is no longer done because there are too many complications in doing it accurately.

 

Nevertheless, in properly engineered composite aircraft, the fatigue life has proven to be longer than was feared. Remember that aluminum has a fatigue limit too. Schleicher recently petitioned the LBA to have the fatigue life limits on their two place trainers removed, because it has proven unnecessary. Originally 3000 hrs had to be inspected by factory, this was subsequently lengthened to 9000 hours, then 18000 hours, now "on inspection" due to experience with the fleet.

 

However I doubt that a J80 had anything like the engineering and testing that goes into even these very limited production aircraft. Take a look at this for an example and a laugh.

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Yes seen that before. The vid of a 747 wing being worked up and down is more impressive I think the tip deflects 18 feet before over stress.

But how about the same test after years of use?

Not to pick on J boats here either the industry is all the same.

What was that model of Swan's where if you tapped the keel the hull always had a 10' x10'x fracture in it. I've seen 2 in Asia (S&S ones in think)

The recognised the failure and re designed the frame and the laminate spec.

 

I want to know who dropped a canter from a height on its side to see how much load was transferred to the rams just before they punch out of the boat.

As far as I can see its all guess work.

This can be calculated of course but that miles about any standards..and where did the standards guys do their testing?

I remember Hobie doing a real world test on a 33 as in dropping it into te water...should be more of it.

 

Maybe buying 4knt SB's and testing to destruction could be a business and sell the data to the insurance companies after the forensics on the failure.

They could love you...upping the premiums on dangerous old boats...mmmmm

 

(Then again they still let J24's sail with their dangerous stability)

PS I will be sailing mine in nice warm water so dont mind a swim but its real deep)

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