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Old 25-05-2014, 09:57   #46
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Re: Cheeki Rafiki

If we could leave aside the " Ive heard Beneteau has a problem" or " Its common knowledge " etc and present some facts and statistics. Then a reasonable conclusion could be arrived at .

Nor do we know what really happened to Cheeki, nor do we know what happened previously. Hence in that void of knowledge the OP is engaging in speculation

To say "keels" should never fall off. Is nonsense. There is always some combination of forces and events that will destroy any part of ANY boat.

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Old 25-05-2014, 10:07   #47
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Re: Cheeki Rafiki

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Originally Posted by Cavalier View Post
What if the prop was dyneema too?

ROTFLMAO
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Old 25-05-2014, 10:14   #48
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Re: Cheeki Rafiki

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Originally Posted by goboatingnow View Post
If we could leave aside the " Ive heard Beneteau has a problem" or " Its common knowledge " etc and present some facts and statistics. Then a reasonable conclusion could be arrived at .

Nor do we know what really happened to Cheeki, nor do we know what happened previously. Hence in that void of knowledge the OP is engaging in speculation

To say "keels" should never fall off. Is nonsense. There is always some combination of forces and events that will destroy any part of ANY boat.

Dave
Nonsense you say? I guess we have far different expectations.

Attaching a narrow fin keel in the manner Bene and others use is similar to edge gluing wood - something that is extremely difficult in any structural application. Why is it acceptable here?

My point was that if an extremely narrow foil is required that there should be a keel stub or cantilever or some device that prevents the total and catastrophic failure of the keel. Even a sacrificial element in the lower portion of the keel which would prevent total loss would be an improvement. The point of failure should be removed from the actual keel attachment point.

And if we don't have lofty expectations, how do things improve?
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Old 25-05-2014, 10:15   #49
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Re: Cheeki Rafiki

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Racing

You know racing puts more stress on any boat often to the point of breaking and with the number of vessels built is it a common occurrence? It is not the only racing monohull that has lost a keel and turned turtle.

I would expect no manufacturer would warrant nor should warrant a 10 year old racing boat.

The unfortunate event simply suggests to all First 40.7 vessels racing should consider a keel rebuild. Consider it racing induced maintaince.

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I'm sorry but I don't believe for a minute that racing puts anything near the stress on the boat as heavy weather does. Being slammed broadside by a large wave, or dropping off one puts severe stresses on the under water part of the hull, keel and rudder. Sailing fast is not even comparable. Boats should be built to take this or be sold as "not suitable for offshore use".
I never for a minute had doubts regarding my molded internal ballast keels in any weather. A bolted on keel would always be in the back of my mind in such conditions. There really is no adequate way to know the condition of the bolts. There are tests and schemes to do so but none of them are conclusive.
Light built boats lose keels in rough conditions, I cant remember how many times I've seen pics of overturned hulls in a world race. No keel attached! These boats were heavily engineered, but the world has a lot of variables....
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Old 25-05-2014, 10:31   #50
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Re: Cheeki Rafiki

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Originally Posted by redsky49 View Post
Nonsense you say? I guess we have far different expectations.

Attaching a narrow fin keel in the manner Bene and others use is similar to edge gluing wood - something that is extremely difficult in any structural application. Why is it acceptable here?

My point was that if an extremely narrow foil is required that there should be a keel stub or cantilever or some device that prevents the total and catastrophic failure of the keel. Even a sacrificial element in the lower portion of the keel which would prevent total loss would be an improvement. The point of failure should be removed from the actual keel attachment point.

And if we don't have lofty expectations, how do things improve?

I not arguing that narrow chord keels present attachment issues. I suspect an examination of Cheeki damage, would show considerable structural damage where the bolts pulled through. I doubt its possible reasonable a reasonable cost, to fix the keel on any better. There are considerable trade-offs in that type of design.

The fact is if you sail that type of boat ( and remember this was a Charter boat) and the crew were just delivery crew. You need to maintain the keel hull joint , just like any other mechanical system on the boat. Its not a "fit and forget" the trouble is , its treated like that .

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Old 25-05-2014, 10:32   #51
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Re: Cheeki Rafiki

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There really is no adequate way to know the condition of the bolts. There are tests and schemes to do so but none of them are conclusive.
Light built boats lose keels in rough conditions, I cant remember how many times I've seen pics of overturned hulls in a world race. No keel attached! These boats were heavily engineered, but the world has a lot of variables....

Correct, and unless regularly dropped and inspected ( like any other mechanical system) it cannot be relied on.


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Old 25-05-2014, 10:37   #52
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Re: Cheeki Rafiki

Are these not SS bolts in a cast iron keel? Sound like a recipe for corrosion to anyone else? I wonder if the European construction standard which says boat fittings are required to last five years and no more comes into play here. They install brass thru hulls based on the same guidelines, knowing they are only going to last a bit more than that five years. Wonder if the same type of reasoning applies here? If you asked them, would they tell you you are expected to drop the keel for inspection after five years and regularly thereafter? If so, are they telling prospective clients this beforehand? Seems like the added cost of regular inspection of integral structural parts of the boat would defray any savings made by buying a cheaper brand...


Using a cast iron ballast keel also restricts construction to keel bolts, instead of the usual studs or "J" bolts which are cast into a lead keel. This means you are relying on the thread of the SS bolt and the thread of the cast iron keel to hold things together. Big difference between this and a cast in J stud.
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Old 25-05-2014, 10:59   #53
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Re: Cheeki Rafiki

Stainless bolts are the cheap seats for holding on keels, yes I know all the production builders use them but crevice corrosion is alive and well with this method.
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Old 25-05-2014, 11:06   #54
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Re: Cheeki Rafiki

Unfortuately lead in hulls is slowly ( or quickly ) going the way of the do do bird. Environmental and safety at work regulations now make it very difficult in Europe to handle lead without serious additional cost.

Stainless in steel in itself isn't really the issue, its the ingress of seawater thats does the damage.

Ive delivered three chartered racing yachts, Other then one which was nearly new, they all looked like they were worked hard.

No easy answer to your question.

Nor is this an issue for European regulations, its important to realise that the RCD is merely a minimum requirement, furthermore to my knowledge there is currently no specific standards on Keels or Keel attachments. There is a draft ISO 12215-9 standard on Keel scantlings, but Im not sure it has been adopted yet. ( it was first published around late 2010)

Heres what the draft ISO standard says

A
Quote:
Alloys containing zincs shall not be used.
All copper based alloys of Table B.1 may be used.
Stainless steels are protected by their oxide layer, which is true when the surrounding medium is oxidant, and when it is clean, polished and passivated. Where this is not true, stainless steel can corrode or rust, particularly Martensitic stainless steel. Some keel bolts have been corroded in places where oxygen is lacking, which is the case when bilge water is stagnant. It is good practice to seal the bolt heads and nuts using sealant or paint.
Fasteners made of metal quoted A2 (AISI 304) in Table B.4 are not recommended if there is any risk of them being under water.
Fasteners made of metal quoted A4 (AISI 316) in Table B.4 are highly recommended, but might be subject to corrosion in a non-oxidizing medium. Care shall be taken when using them on wooden craft where they will be submerged in de-oxidized water.
the primary thrust of ISO 12215-9 is that the forces on the keel are capable of being carried by the structure

The draft can be read here https://law.resource.org/pub/bg/ibr/...215-9.2012.pdf ( ignore the first few pages in Bulgarian, the standard is in English)

This is an extremely technical standard and is an indication of how the later ISO standards for small craft are becoming more rigours and science based.

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Old 25-05-2014, 11:19   #55
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Re: Cheeki Rafiki

Yes Dave I understand that you need saltwater to get SS to corrode but there are other choices that are very strong and impervious to crevice corrosion but a builder who saves a few bucks installing brass thru hulls will never spend the extra money would they?
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Old 25-05-2014, 11:27   #56
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Re: Cheeki Rafiki

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Yes Dave I understand that you need saltwater to get SS to corrode but there are other choices that are very strong and impervious to crevice corrosion but a builder who saves a few bucks installing brass thru hulls will never spend the extra money would they?
This all boils down to the "limits of the envelope " design argument, No more then using brass or often DNZ or stainless underwater argument, the issue is about where you draw the line. Builders like Beneteau and others have been in business a long time, so I suspect that they have built up considerable knowledge on what works and what doesnt.

Ive been on countless European boats with 10 year + thru hulls, sitting happily above the water. !

Equally I don't know the precise specification of the bolts on the hulls it could be enhanced stainless, like Aquamet or similar etc. I don't really know.

I don't really think this is the issue, this was a charter racing boat, taken in a area known for bad weather, when other routes were clearly available. We don't know what storm surviual actions were taken, nor have we any idea of the "event cascade" that always precedes such tragedies. The keel being ripped off, is merely the end result we see.


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Old 25-05-2014, 11:28   #57
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pirate Re: Cheeki Rafiki

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Originally Posted by robert sailor View Post
Yes Dave I understand that you need saltwater to get SS to corrode but there are other choices that are very strong and impervious to crevice corrosion but a builder who saves a few bucks installing brass thru hulls will never spend the extra money would they?
I'm sure they'd be only to happy.. if you'd be prepared to pay the higher price.. however.. usually that's the rub..
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Old 25-05-2014, 11:32   #58
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Re: Cheeki Rafiki

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Originally Posted by socaldmax View Post
If it was a design flaw, you'd have seen keels falling off left and right. A few keels falling off here or there could be lack of maintenance, prior damage that went uninspected or unrepaired, or being subjected to repeated abuse/forces/weather beyond that which it was designed for.
Not really. There have been a couple of cases where keels have hit something big enough to sheer keel bolts. Especially SS in Iron where an egress of salt water can corrode them to an hour-glass shape. What might appear to be a 25mm.+ bolt could easily be corroded down to 12 mm. A good joly might do the rest. Remember most plastic bars of soap end up being dock queens. Not much can hurt them in a safe slip.

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Originally Posted by goboatingnow View Post
If we could leave aside the " Ive heard Beneteau has a problem" or " Its common knowledge " etc and present some facts and statistics. Then a reasonable conclusion could be arrived at .

Nor do we know what really happened to Cheeki, nor do we know what happened previously. Hence in that void of knowledge the OP is engaging in speculation

To say "keels" should never fall off. Is nonsense. There is always some combination of forces and events that will destroy any part of ANY boat.

Dave
I would go out on a limb and say my 3/4 full keel HR, won't be falling off anytime soon.
[QUOTE=robert sailor;1549508]Stainless bolts are the cheap seats for holding on keels, yes I know all the production builders use them but crevice corrosion is alive and well with this method.[/QUOTE+1...Yes...see my first comment.
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Old 25-05-2014, 11:33   #59
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Re: Cheeki Rafiki

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Originally Posted by minaret View Post
Are these not SS bolts in a cast iron keel?...
The early First series used steel bolts in cast iron.
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Old 25-05-2014, 11:37   #60
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Re: Cheeki Rafiki

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Originally Posted by goboatingnow View Post
If we could leave aside the " Ive heard Beneteau has a problem" or " Its common knowledge " etc and present some facts and statistics. Then a reasonable conclusion could be arrived at .

Nor do we know what really happened to Cheeki, nor do we know what happened previously. Hence in that void of knowledge the OP is engaging in speculation

To say "keels" should never fall off. Is nonsense. There is always some combination of forces and events that will destroy any part of ANY boat.

Dave
Never seen an example of a molded in keel parting with the boat... unless it was abandoned on a rocky beach!
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