Hull Failure!

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No, not the S28. This was on a large (60ft+), new-ish, and very expensive American sportfisher type thingy with a cored hull which didn't like the bumpy bits. Manufacturer name omitted to spare the blushes.

I think the sea trial can safely be classified as a "Fail".

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Wow that's some failure. I'd heard stories about a cruiser manufactured in EU where the hull was layed and fabricated in two separate halves (ie port and starboard) but then joined down the length of the keel. Seems a recipe for disaster, and there were mutterings about leakes and splits down the keel. It doesn't bear thinking about what could happen in a decent head sea!
 
that is a Bertram 630 a US builder part of Ferretti Group since 1998, I was gonna make a post of it today as it is running in US forums since last week
big hull delamintation, full stop
from a builder who has build its reputation for building never ending trouble free hulls from this sort of thing and other stuff like blistering, Bertram used to be osmosis free boats in the worst period of this disease
apart the superb performance Bertram offered
who made the mistake hard to know...
only builder to do this not really I can make a list of all builders in boating really, but Bertram where not able to cover up this
interesting is David Pascoe YachtSurvey.com comments here
 
LOL that which seperated is the gelcoat and first polyester coat
you still have the fibre mat which in the picture most of it seems to be down in the Atlantic and the coring so it is not that really thin
the gelcoat seems to be about 2 / 1.5 mm so it is normal really if not better than most
I worked on a FL43 and 1/1.5 mm gelcoat in the bottom the same an AZ46
 
Reading David Pascoes 'survey' report makes for some chilling reading. He highlights the challenges in making vacuum bagged foam core structures. Size for size these are much stiffer than solid mouldings whilst being much lighter, good qualities but quality control is paramount. When you are paying for a brand label QC is what you expect to be paying for.

The voids and faults in the layup are plainly visible. A complete failure in their QC I'd say.

In response to the post about boats in two halves ....

Sailplanes fuselages and wings are made as two shell halves. Fuselage left and right joined longitudinally and wings top and bottom joined along leading and trailing edges. The joints tend to be the over engineered parts!

There was an incident a few years back where following the in flight brakeup of an aircraft a bunch of wings were found to have somewhat less than a safe amount of glue connecting the top and bottom halves of the wings.
 
Just out of interest would a standard survey pick up such a catastrophic problem ? (I mean before it fell apart ...) /forums/images/graemlins/shocked.gif

The linked story on the US site re : the balsa cored 72' er is a bit of an eye opener too, although thats not a new problem.

Not that I've got a few million burning a hole in the pocket sad to say ..

But its a shocker all the same.
 
on the other US forums many surveyor say they can spot this
I think it is very difficult from a brand new build perspective, unless you dont have a hard costing cash equipement
I have a review in an Italian mag of a few years ago where there is laser sonar equipment which can check the tickness and tell what materials more or less it has whether it is fiber etc and give you a reading of the materials
this costed a few tens of thousand euros and if memory tells me right it is patented
to be honest but then it is the builder who really has to check and buy this, the bigger the name the more they have to check
you dont pay a million plus for a boat and then have this result or do you
 
Hi there, im new here but i saw this happen once on a jet ski, the reason was quite simple - after a long debate between the repairer and the builder.But this is what was found..

The gel coat was applied in the mould at the factory in the usual way and as soon as the gel was tacky the first layer of matting was applied, so far so good but this was on a friday afternoon...

On the monday the next layer of matting was applied in the normal way and the construction contiuned.. Modern resins are quite 'waxy' its a side effect of reduced styrene emmission. So a fresh layer of resin and matt were applied to a 'waxy' dry layer causing a weak connection and it fails to bond correctly so in principle you have a weak bond between the primary bond and the secondary bond which can realese and the consequeses are quite dramatic. Se pictures above

Can you tell if this exists before it fails? Very difficult, a core sample gets too hot to really give you any useful data unless its big enough to remain cool in the middle of the sample. A extremly skilled surveyor/ boat builder could hear the 'loose' connection with a hammer test but its not gauranteed.

Basically the boat builder needs to be very competant with any lay ups that are left to 'dry' are keyed up with abrasives and softened with acetone prior to further lay up.
 
I would think a hammer test would have picked this up - when we had our boat surveyed for MCA cert. was surprised that the only equipment the quite expensive surveyor arrived with for out of water survey was a clipboard and hammer! Wasn't keen on him hitting my new boat with it but he insisted /forums/images/graemlins/frown.gif
 
here is what someone nicknamed Bertram09 said on the US Yachtforum, look someone official from the company really
QUOTE
Bertram Yacht's Response- 630

Based on the information presently available and evaluations made to date by Bertram, the situation with the 630 is an isolated problem unique to that particular boat and does not represent a systemic problem in design or construction present on other 630 hulls.
UNQUOTE

I hope that they check all ther new and recent boats (2008)after this mess so it is sure it will not be repeated. First is because that is a lovely boat 2 is because this is a legendary name and it is a pity if it finishes for this. Hell better going bankrupt as in the past for building over expensive and super enginnerred boats.
 
Hmmm. Fact is they don't know. They didn't know the laminates on this were held together by fresh air so how do they know about the other hulls they've made?
 
Re hulls being laid up in two longitudinal halves and then being bonded together - the FRP Mersey class carriage launched lifeboats operated by the RNLI are all built this way..... but they do have a VERY substantial joint along the keel!

Many sailing yachts with tumblehome (where the beam at deck level is less than the maximum hull beam) had to (of necessity) be built this way, as otherwise they would not be able to pull the hull from the mould.
 
On photograph number 5,what looks like some impact damage is visible in the centre of the loose sheet of laminate.
Looks as though this was caused by the boat hitting something external,a pile or finger berth,perhaps this was the first thing that caused the subsequent problems.
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