ANOTHER MAJOR KEEL FAILURE: What Really Happened to Polina Star III?

[dom]

Obviously the keel falling off is never a good situation, but if it were to happen to me I would rather have 6 minutes warning than nothing

Yeh, I think we basically agree; all I'm saying is that the six minutes was a function of the vessel being in med F3 as opposed to a Pacific F10, where it might have been more like 15 seconds. So a vital time advantage appeared, but by good fortune as opposed to good design.

 

[bedouin]

Yeh, I think we basically agree; all I'm saying is that the six minutes was a function of the vessel being in med F3; in a Pacific F10 it might have been more like 15 seconds. So a vital time advantage appeared, but by good fortune as opposed to good design.

Yes - but we are guessing. In this instance the boat was good enough for the crew to survive - so it a bit harsh to say that is completely down to luck.

Given that the failure caused the hull to peel rather than sheer off (a la Bavaria Match or Beneteau 40) suggests that even in a Pacific F10 there would have been a bit of warning

 

[Owl]

Taking a step back, standard engineering practice for critical systems would be to match the inspection regime to the time from the problem being detected to failure.

In the case of a cruising yacht this means the keel should last around 1 year from any problem starting given that cruising boats only come out of the water once per year.

This isn't impossible - the safety systems on a car need to have a similar failure timescale given modern maintenance schedules.

An alternative might be to embed detectors (strain gauges, breakable wires) in the hull & keel to provide early warning, although making such detectors reliable in the marine environment would be a problem in itself. Probably wouldn't cost too much if added at build time.

 

[30boat]

I think the same whenever I see a car transporter or modern cruise ship.

Occasionally we yottie's have our instincts proven right ( thing on it's side on Bramble Bank, Costa A Carreera ) but generally these motor vessel people seem to work on the ' Stagecoach Principle '; " The last one made it, off you go ! "

If I were helming one of those boats I'be be really careful with the trottle when turning.

 

[dunedin]

U

Yes - but we are guessing. In this instance the boat was good enough for the crew to survive - so it a bit harsh to say that is completely down to luck.

Given that the failure caused the hull to peel rather than sheer off (a la Bavaria Match or Beneteau 40) suggests that even in a Pacific F10 there would have been a bit of warning

This reminds me of John McEnroe - "you can not be serious!"

This was a world cruising boat - and the whole keel structure reportedly broke off in very moderate conditions. It simply should be engineered so it could never come off, certain not in these circumstances. 6 minutes to capsize is perhaps just due to the light conditions and inherent form stability, like the amazing Jeaneau SO.
But almost no time for a sleeping crew to get out - and in any form of rough weather might have been much quicker. As for a proper storm in an ocean ......

 

[JumbleDuck]

It transpires that the trawler yacht was 8000lbs heavier to port and had less ballast on board than reported to the naval architect (http://www.ntsb.gov/investigations/AccidentReports/Reports/MAB1514.pdf). It was never going to make it....

Good job the owner had someone on hand to check the quality of the work. Perhaps in retrospect it would have been better to have someone on hand who was actually qualified to check the quality of the work, but hindsight is easy.

 

[bedouin]

There was a lot of discussion about detecting pending failures in the follow up to the Cheeki Rafiki incident - I am no expert but I seem to recall the consensus was that it was virtually impossible to do in that case.

In this case we need a reasonable hypothesis of what was trigger for the failure before we could suggest what form of precautions could be taken.

 

[dom]

In this case we need a reasonable hypothesis of what was trigger for the failure before we could suggest what form of precautions could be taken.

The trouble is a hypothesis needs facts to explain, but all we have here are some carefully finessed legal/PR statements from Oyster and some shocking photos from an intrepid Russian journalist.

 

[pmagowan]

Taking a step back, standard engineering practice for critical systems would be to match the inspection regime to the time from the problem being detected to failure.

In the case of a cruising yacht this means the keel should last around 1 year from any problem starting given that cruising boats only come out of the water once per year.

This isn't impossible - the safety systems on a car need to have a similar failure timescale given modern maintenance schedules.

An alternative might be to embed detectors (strain gauges, breakable wires) in the hull & keel to provide early warning, although making such detectors reliable in the marine environment would be a problem in itself. Probably wouldn't cost too much if added at build time.

That is interesting. I think it was Viv who brought up about keel bolts with strain detection on them in another thread. This seems like a reasonable idea but it would also be interesting if it was possible to monitor the strain in the hull itself. Another thing is that parcels are now often monitored to detect if they have been manhandled. A boat could easily be fitted with a collision detector in order to help maintain a proper history of groundings and repairs.

An interesting paper on this:
http://www.usna.edu/Users/naome/phmiller/j-24fatigue.html

 

[bbg]

Taking a step back, standard engineering practice for critical systems would be to match the inspection regime to the time from the problem being detected to failure.

In the case of a cruising yacht this means the keel should last around 1 year from any problem starting given that cruising boats only come out of the water once per year.

This isn't impossible - the safety systems on a car need to have a similar failure timescale given modern maintenance schedules.

An alternative might be to embed detectors (strain gauges, breakable wires) in the hull & keel to provide early warning, although making such detectors reliable in the marine environment would be a problem in itself. Probably wouldn't cost too much if added at build time.

I'm sorry but that is not a serious suggestion. Keels should be designed not to fail at all. It is difficult to imagine that kind of structure failing slowly and safely. The objective should not be to design something that, if it fails, fails safely. The objective should be to design things that don't fail. If that means building in some safety margins, that should be done.

In this particular instance there seem (to me) to be four possibilities. Failure in design, failure in materials, failure in workmanship or misoperation. Or a combination.

But we must also remember how many yacht roll out of yards each year. Although this is a catastrophic failure it is extremely uncommon. So uncommon that, apart from outright push-the-envelope racers, I can think of only a handful of keel failures from boats built in the last 15 years or so, and at least three of those were eventually put down to groundings that were not properly reported or repaired. In fact this is the only non-racer that I can think of that had keel failure without any reported "incident".

 

[Tranona]

In fact this is the only non-racer that I can think of that had keel failure without any reported "incident".

Really important to remember this. The safety margins are normally massive as anyone who has read the ISO and the explanation of its formulation from the Wolfson Institute when it was recently revised, will know.

Clearly in practice the safety margins are robust as failures in "normal" use - that is from forces experienced in sailing boats in the conditions for which they were designed - are almost non existent. So there seems something about this boat and failure that is atypical which makes it even more important that a proper analysis of the cause(s) is made available for all.

The way Oyster are handling this reminds me of the way Bavaria handled the loss of the keel of a Match 42 in Croatia. There was almost certainly a rational explanation as all sister boats to similar designs were subsequently modified, but Bavaria refused to admit any failure, blaming it on third party actions. The lack of openness did them a lot of harm such that even 10 years later the "jokes" on the subject still circulate. Poor handling of a negative incident has a long lasting effect as Thomas Cook are now discovering after their appalling handling of the deaths of two children in Corfu. No doubt it will take years for VW group to recover from their current woes as well.

 

[johndove]

Cheeki Rifiki took 48 hours approx when warning and problem started, then keel was lost. Also on old well used boat.

This Oyster took 6 minutes, almost new boat

Are the safety margins to small now? Was on this one. We would expect Oyster to have a very good quality control.

Are safety margins on new boats to small. Never heard of a yacht tested like new car design are. Test to destruction.

All calculations by the design team. Guess designers always trying to save weight as weight equals cost and speed.

Are they going to far, time will tell.

 

[sailorman]

Cheeki Rifiki took 48 hours approx when warning and problem started, then keel was lost. Also on old well used boat.

This Oyster took 6 minutes, almost new boat

Are the safety margins to small now? Was on this one. We would expect Oyster to have a very good quality control.

Are safety margins on new boats to small. Never heard of a yacht tested like new car design are. Test to destruction.

All calculations by the design team. Guess designers always trying to save weight as weight equals cost and speed.

Are they going to far, time will tell.

Where is the logic in saving build weight only to all 1 tonne of lead ingots in the bows

 

[johndove]

Where is the logic in saving build weight only to all 1 tonne of lead ingots in the bows

Thought it was bricks and concrete? That is the design team getting it wrong.

 

[sailorman]

You need to do more reading :encouragement:

 

[sailorman]

More PISH Sailorman. This loophole was closed years ago, you cant just go in and say I dont want to pay the VAT.....

More PISH here Losser


Re: Buying from Belgium

Originally Posted by rlw
Regarding the VAT question as long as the boat is registered in Belgium it means that the VAT status has been verified. Otherwhise you cannot get a registration number.
You have to prove VAT status on the application.



theoretically that is correct, but I have one example where I didn't have proove, and another example where I didn't pay vat on the boat, and I got perfectly legally a Belgium registration,

The Karnic, I have bought by my Belgian company from a Austrian dealer, ex vat (Intra community)
Boat is owned by a Belgium VAT registered co, and I 've got a B registration without a problem,
(when I ever sell her in Belgium, I have to charge VAT ofcause, on the remaining value)

Blue Angel, I bought from a Italian co, ex vat in a Belgium VAT registered company.
actually one of the previous owners has paid VAT in Italy, selling the boat from one co to another, but I have no proove of that,
so officially no Vat payed, and I've got a B registration.

but back to the topic here;
IIRC the boat that OP wants to buy, has been sold new to the first owner, by current broker / dealer,
so they can provide clean VAT paperwork


http://www.ybw.com/forums/showthread.php?445278-Buying-from-Belgium

​

 

[Seajet]

Yeh, I think we basically agree; all I'm saying is that the six minutes was a function of the vessel being in med F3 as opposed to a Pacific F10, where it might have been more like 15 seconds. So a vital time advantage appeared, but by good fortune as opposed to good design.

I'm sure most people would be jolly glad of the 6 minutes to get off - weather being kind - but as I have a Scottish Dad & upringing, if I'd signed the cheque I might be a bit miffed, to the point of ' doing a Braveheart ' but a better ending via lawyers !

 

[mainsail1]

Keel failure in modern cruising yachts is not rare. What is rare is that the failure is not detected before a disaster occurs. Thank goodness for luck! When the keel on my Bavaria 44 nearly fell off after delaminating the surrounding hull the surveyor said he had seen at least ten previous examples amongst modern AWBs. To my mind, it is unforgivable for a keel to fall off even if it has hit fishing nets or run aground. Some modern yacht builders seem to have forgotten that when it comes to keel attachment the design has to follow a 'belt and braces' route.

 

[lw395]

There is also a bit of an elephant in the room here, any guesses ?

Begins with ' D ' and ends with ' M '.

Darwinism?

 

[Tranona]

More PISH here Losser


Re: Buying from Belgium

Originally Posted by rlw
Regarding the VAT question as long as the boat is registered in Belgium it means that the VAT status has been verified. Otherwhise you cannot get a registration number.
You have to prove VAT status on the application.



theoretically that is correct, but I have one example where I didn't have proove, and another example where I didn't pay vat on the boat, and I got perfectly legally a Belgium registration,

The Karnic, I have bought by my Belgian company from a Austrian dealer, ex vat (Intra community)
Boat is owned by a Belgium VAT registered co, and I 've got a B registration without a problem,
(when I ever sell her in Belgium, I have to charge VAT ofcause, on the remaining value)

Blue Angel, I bought from a Italian co, ex vat in a Belgium VAT registered company.
actually one of the previous owners has paid VAT in Italy, selling the boat from one co to another, but I have no proove of that,
so officially no Vat payed, and I've got a B registration.

but back to the topic here;
IIRC the boat that OP wants to buy, has been sold new to the first owner, by current broker / dealer,
so they can provide clean VAT paperwork


http://www.ybw.com/forums/showthread.php?445278-Buying-from-Belgium

​

None of that has any relevance to this boat and owner, nor as indicating there is any validity to the general point you are trying to make about how boats such as Oysters are owned and whether they are liable for VAT.

Please if you want to contribute to this thread, restrict yourself to discussion about the design and build of the boat, not going off into irrelevant subjects, particularly as you seem to know very little about them.