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

Tranona said:
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.
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It was a reply to LOSSER who doubted the funding of yachts via a 3rd party to off-set interest charges & VAT liability , .
The whole discussion here as to the design is pure conjecture & i am sure you would be amongst the first to agree.
 
Owl said:
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.
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Again this would be long standing aircraft technology, but I seem to remember Very Large tankers etc have bow pressure plates so the skipper can judge if he's pushing too hard 1'000 ' ahead.

The snag with strain guages, fire wires etc is they all introduce complexity and training; a laudable idea, were it not for the shipping industry practice of employing cheap clueless eastern crews interspinkled with drunk European skippers...

Maybe better spend development money on a robot arm to vigorously prod the OOW every few minutes with a pointy stick.
 
Seajet said:
Again this would be long standing aircraft technology, but I seem to remember Very Large tankers etc have bow pressure plates so the skipper can judge if he's pushing too hard 1'000 ' ahead.

The snag with strain guages, fire wires etc is they all introduce complexity and training; a laudable idea, were it not for the shipping industry practice of employing cheap clueless eastern crews interspinkled with drunk European skippers...

Maybe better spend development money on a robot arm to vigorously prod the OOW every few minutes with a pointy stick.
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I think you will find there is a load cell; under the mast foot to assist with setting up the rig loads
 
sailorman said:
It was a reply to LOSSER who doubted the funding of yachts via a 3rd party to off-set interest charges & VAT liability , .
The whole discussion here as to the design is pure conjecture & i am sure you would be amongst the first to agree.
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It may be conjecture given the shortage of reliable information, but I bet much of it will turn out to be close to the mark.

On the other hand everything you have tried to say about VAT in relation to this type of boat is nonsense.

It would help if you want to raise it as an issue you do so in a separate thread and explain clearly what it is you are trying to say instead of your usual garbled one liners or inappropriate posting of bits out of other peoples' posts.
 
pmagowan said:
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.
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I would not be surprised to find that in this case the keel bolts were torqued correctly but movement between the outer hull and inner grid structure caused a relaxation in the tension of the bolts. The same occurred in subsequent retorquing. I would be really surprised if Oysters QC did not ensure the bolts were correctly tightened. Any failure would be why the need to re tighten these bolts was not investigated. That was definitely a suck it and see attitude.

It must be difficult to establish the adequacy of the bonding of inner grid structure and the hull. The photos indicate to me that the way the hull was peeled away it was not bonded adequately irrespective of whether the basic design was inadequate
 
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Sailfree said:
I would not be surprised to find that in this case the keel bolts were torqued correctly but movement between the outer hull and inner moulding caused a relaxation in the tension of the bolts. The same occurred in subsequent retorquing. I would be really surprised if Oysters QC did not ensure the bolts were correctly tightened. Any failure would be why the need to re tighten these bolts was not investigated. That was definitely a suck it and see attitude.

With the bonding of inner and outer hulls it must be difficult to establish its adequacy. The photos indicate to me that the way the other hull was peeled away it was not bonded adequately irrespective of whether the basic design was inadequate
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I didn't see any evidence of an inner hull.Only stringers.
 
bbg said:
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.
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Everything fails sooner or later - the trick is to design it so that we do something before it causes a problem. While it is fairly straight forward to design a long-keeler to take most things that can be thrown at it - including grounding, nets, poor maintenance etc - with a modern high-aspect keel this is very hard to do. If the end of a high-aspect keel hits something other than water the loads will be huge, and given the materials used, weight limits and cost limits something is likely to break.

So how do we know that a failure has started before it becomes critical? As structures become more optimised it gets harder and harder to inspect the structure while any damage or imperfections become more critical.
 
Tranona said:
It may be conjecture given the shortage of reliable information, but I bet much of it will turn out to be close to the mark.

On the other hand everything you have tried to say about VAT in relation to this type of boat is nonsense.

It would help if you want to raise it as an issue you do so in a separate thread and explain clearly what it is you are trying to say instead of your usual garbled one liners or inappropriate posting of bits out of other peoples' posts.
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Post 100 is perfectly clear
set-up a Co ( in Belgium ) & buy a boat VAT free + any running costs would also be VAT free, What do you not understand about that post
 
sailorman said:
Post 100 is perfectly clear
set-up a Co ( in Belgium ) & buy a boat VAT free + any running costs would also be VAT free, What do you not understand about that post
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That is not what he was saying. He was just explaining specific situations, not a general rule. You can set up a company in the UK and reclaim VAT on a boat IF you meet the HMRC requirements for it to be considered a business asset.

I am afraid the lack of understanding is on your part - just reading what you want to see, rather than actually understanding what is being said.

There are many ways in which a boat can be owned with or without paying VAT, but all those that avoid VAT come with constraints on private usage of the boat. The boat in this thread is a good example. The owner is non EU resident, the boat is normally outside the EU, it is registered outside the EU. So there is no basic reason why he should pay VAT. If he wishes to bring it into EU waters he has to apply for TI and that brings restrictions on its use. I am pretty sure that he will comply with all the rules, and probably use his captain to ensure that he does. Other buyers of boats such as Oysters will arrange their affairs to minimise their tax and there is nothing illegal about it. You could do exactly the same if you were prepared so accept the same conditions.

So the notion that just setting up a company in Belgium and you can avoid VAT is, as I said just nonsense.
 
Owl said:
Everything fails sooner or later - the trick is to design it so that we do something before it causes a problem. While it is fairly straight forward to design a long-keeler to take most things that can be thrown at it - including grounding, nets, poor maintenance etc - with a modern high-aspect keel this is very hard to do. If the end of a high-aspect keel hits something other than water the loads will be huge, and given the materials used, weight limits and cost limits something is likely to break.

So how do we know that a failure has started before it becomes critical? As structures become more optimised it gets harder and harder to inspect the structure while any damage or imperfections become more critical.
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That is just wrong. The vast majority of yachts built today have fin keels attached to the hull in some manner. Not long keels. So it can't be "very hard to do" because it is in fact done, to the tune of tens of thousands of boats each year.

Again, I am not aware of a single instance in which a boat with a fin keel grounded (your scenario) and immediately sank. Of course I am aware of some instances where there was a grounding and the keel subsequently fell off, but not immediately.

Cars are specifically designed to have crumple zones to protect the occupants. They could be designed to be undamaged in a collision up to 20 mph but they aren't. Does the fact that the might be written off in a 10 mph fender bender mean the design is bad? Of course not.

A fin keel boat might need repairs after hitting a rock at hull speed and will certainly need to be carefully inspected. Repairs might not be economical. But that doesn't make it a bad design. And once again, I am unaware of a normal (non-racer) boat that has immediately lost its keel upon impact with something. Can you point us to an example?

If the problem with the Oyster yacht turns out to be a problem of materials or workmanship, that cannot be an indictment of fin keels. Even if it turns out to be a design flaw, that is not an indictment of all fin keels, just a reflection on the design of this one.
 
bbg said:
Again, I am not aware of a single instance in which a boat with a fin keel grounded (your scenario) and immediately sank. Of course I am aware of some instances where there was a grounding and the keel subsequently fell off, but not immediately.
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It happens - there have been a couple of examples in the Solent where yachts have hit Brambles bank and lost their keels.
 
As an Oyster owner (an old one - 485) I do think that the design has moved to a more intrinsically weaker design. When looking at the hulls I preferred the "wine glass" shape of the hull blending into the keel rather than the bolting of a perpendicular keel to a semi circular hull. Not as fast as the modern design but the stresses in the older (Holman & Pye) hull are, by common sense, less acute. I was much reassured that when I had to put a new hull penetration in last year the fibre glass was just shy of 50mm thick near the curve of the hull towards the keel.

Sadly it does appear to me that the new owners are putting more emphasis on profit rather than fine building. Their move into the large super-yacht market is a shame since I think they built very fine yachts in the '80s and 90s without compromise, although even then there were some notable dodgy hulls with balsa laminate being extended below the water line on some models. You need to be careful buying one of those lest you buy some balsa mush!!!

Still companies are always going up or down. I think the downturn came when the original inspiration for the "Oyster" retired from the organisation. i.e. Richard Matthews

For my part I think the yacht is first rate and as I have dug around it repairing and replacing I have only found a really good quality build from Windboats - (built in Wroxham too!!!)

cheers,
 
DickB said:
As an Oyster owner (an old one - 485) I do think that the design has moved to a more intrinsically weaker design. When looking at the hulls I preferred the "wine glass" shape of the hull blending into the keel rather than the bolting of a perpendicular keel to a semi circular hull. Not as fast as the modern design but the stresses in the older (Holman & Pye) hull are, by common sense, less acute. I was much reassured that when I had to put a new hull penetration in last year the fibre glass was just shy of 50mm thick near the curve of the hull towards the keel.

Sadly it does appear to me that the new owners are putting more emphasis on profit rather than fine building. Their move into the large super-yacht market is a shame since I think they built very fine yachts in the '80s and 90s without compromise, although even then there were some notable dodgy hulls with balsa laminate being extended below the water line on some models. You need to be careful buying one of those lest you buy some balsa mush!!!

Still companies are always going up or down. I think the downturn came when the original inspiration for the "Oyster" retired from the organisation. i.e. Richard Matthews

For my part I think the yacht is first rate and as I have dug around it repairing and replacing I have only found a really good quality build from Windboats - (built in Wroxham too!!!)

cheers,
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That's interesting. There's a queer diffence between your 50mm and this one's 15mm, and with an obviously weaker shape.
 
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AndrewfromFal said:
What looks like a pretty comprehensive response has just been put out by Oyster

http://www.oysteryachts.com/breaking_news/304/Update-on-Polina-Star-III-Southampton-08-December-2015/

It's light on specific technical detail, but the bottom line appears to be that they found a possible build process defect on the sisterships and have corrected it, and will be reverting to a process used on their other boats.
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To be precise they didn't say they had found the problem on the sister ships.

Sounds like a good and professional response from Oyster - checking all the boats that can possibly be impacted.

I
 
bedouin said:
To be precise they didn't say they had found the problem on the sister ships.

Sounds like a good and professional response from Oyster - checking all the boats that can possibly be impacted.

I
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Agreed. I think the key phrase is

'....our inspection of the other 825s (not including Polina Star III) highlighted a possible weakness in the process used to build the inner structure of those vessels. This process has not been used on any other Oyster Yacht built over the last ~40 years and will not be used again'
 
bedouin said:
To be precise they didn't say they had found the problem on the sister ships.

Sounds like a good and professional response from Oyster - checking all the boats that can possibly be impacted.

I
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A new build process. 3 out 4 boats using that process rebuilt, 1 out of 4 boats sunk, and now abandoning that process from boat 5 onwards. Sounds like a pretty good admission that "we f***ed up" to me.
 
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