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Old 05-04-2016, 19:10   #76
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Re: Dutch couple found dead, their sailboat found upturned

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Originally Posted by Polux View Post
The information is not related to the article but with a search ISAF had made regarding the causes of 72 keel failures since 1984, regarding all types of keel boats and it seems to me that welded fins means just that, fins that are secured through welding and that can only regards aluminium or steel boats.
That (Bold) Pollux is where we disagree.

Maybe Someone can source the ISAF and confirm. I think it's a case of the writer mucking up the language. I know that's hard to believe.
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Old 05-04-2016, 19:14   #77
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Re: Dutch couple found dead, their sailboat found upturned

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Once, a long time ago I tried to figure out how much foam I would need to float my boat. Can't recall details but it ain't gonna happen. You would end up with a coffin for an interior.
I'm short about 100 cubic feet of foam for a buoyant Panope. I could achieve this by sacrificing the lazarette and storage underneath bunks and settees. For my current use of the boat (no live-aboard, no big off-shore trips, etc.), this is feasible.

Steve
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Old 05-04-2016, 19:21   #78
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Re: Dutch couple found dead, their sailboat found upturned

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Yeah, that language in the article is poor. But in the context of the article it is absolutely clear he is talking of modern production boats. I think if he used the word "bulb" it would have been more clear that he was talking about an appendage on the bottom of a keel. He clearly makes a distinction between a "fin" and a "keel."

I PRESUME these "fins" are of welded construction, thus "welded fin". Obviously you can't weld to fiberglass. So these fins were welded to attachments coming down from the boat or had long threads going through the hull into the boat. I don't know, how would you attach a bulb or torpedo to a keel?

I THINK his point was that the Failure can be at the top of the ballast fin, not where the bolts come through the keel into the hull.
Again, that research it has nothing to do with article but it is a research made to all type of boats since 1984 by ISAF, obviously mostly not modern boats.

Only very high performance high quality racers have welded keels, using a light welded structure as a foil to where a lead bulb is attached and not welded and not many.

Bulbed keels on production boats or torpedo keel are not welded and torpedo keels are only used recently on mass production boats and are all iron. Not any problem with the torpedos regarding those.

On that survey they talk about keels suspended by bolts and immediately after about keels secured by welding. It seems to me that the meaning is clear.
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Old 05-04-2016, 19:23   #79
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Re: Dutch couple found dead, their sailboat found upturned

Pollux,

Let's not argue. I found a link to the ISAF tabulation. You can decipher this a whole lot easier than I can.

Please take a look and see what you make of it. At my first glance I don't see any steel boats on the list but I could be wrong.

http://www.sailing.org/tools/documen...ailuresdatav2-[17112].pdf
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Old 05-04-2016, 19:27   #80
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Re: Dutch couple found dead, their sailboat found upturned

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I'm short about 100 cubic feet of foam for a buoyant Panope. I could achieve this by sacrificing the lazarette and storage underneath bunks and settees. For my current use of the boat (no live-aboard, no big off-shore trips, etc.), this is feasible.

Steve
Right, you are aluminum, I'm steel. I'm live aboard cruiser.
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Old 05-04-2016, 19:33   #81
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Re: Dutch couple found dead, their sailboat found upturned

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...
What about swing keels? Any comments on those? One would think that as those boats will sail even with the keel all the way up, due to having a stub keel, that they would not have a problem.
....
They talk about two cases with a swing keel system and I know at least one. Probably both refer to cases with IMOCA boats that had lost the keel without any collision. The problem was identified and had to do with a inadequate stress evaluation in what regarded metal fatigue.

That had to do with swing keels being used for the first time extensively in several circumnavigation races and several transats. After those cases all the boats started using mandatorily a common system as a way to gather faster information regarding eventual problems, but till now, several years after that none of the boats had problems in what regards the canting mechanism and the way the keel is hold.
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Old 05-04-2016, 19:36   #82
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Re: Dutch couple found dead, their sailboat found upturned

Pollux,

Here I looked up the first one mentioned, ACCONIA.

Deffinetly NOT a steel or aluminum hull.

Quote:
The ACCIONA 100% Ecopowered also features a range of new materials and naval engineering innovations resulting from exhaustive research and quality controls carried out with ultrasound technology.

The keel -the part of the hull below the waterline- is made from new-generation composite materials and has been put through its paces with non-destructive testing. Its hydrodynamic design came after seven prototypes tested on a 1:7 scale in a hydrodynamic testing channel and as a result of software studies based on fluid dynamics in order to determine the optimum configuration. The final keel was analyzed on a scale of 1:3 with a range of appendage configurations at the hydrodynamic testing station at El Pardo (Madrid, Spain).

The vessel's deck was conceived as a structural element to keep down the number of struts for the hull; it has a superstructure (coach roof) based on "stealth" aircraft made from carbon fiber which is lightweight and reduces drag as the yacht moves forwards.

The carbon fiber mast is set back slightly compared to a conventional IMOCA 60: this reduces the surface of the mainsail and the weight of the boom and increases the surface of the sails at the bow, improving performance with the wind in favor.
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Old 05-04-2016, 19:39   #83
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Re: Dutch couple found dead, their sailboat found upturned

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Pollux,

Let's not argue. I found a link to the ISAF tabulation. You can decipher this a whole lot easier than I can.

Please take a look and see what you make of it. At my first glance I don't see any steel boats on the list but I could be wrong.

http://www.sailing.org/tools/documen...ailuresdatav2-[17112].pdf
I like your attitude and if I am wrong I will be the first to tell but the link you provide does not work. Please try again, maybe something missed when you posted it.

Edit: I accessed it and it is an odd list. Almost all the boats are race boats and they even got wrongly one of the few that is not a race boat but a cruiser racer. It was a Bavaria Match 42 and not 38 that lost the keel, as it is stated there and even I know about some more keels lost on cruising boats than the ones that are listed there.

And yes you are right nothing of that has to do with steel or aluminium boats but with canting keel boats, canting mechanisms, welds there and probably on the type of keel structure that I mentioned previously.

Who would thought that on an article about cruising boats they would refer information regarding keels lost on pure racing boats whose keels have little to do with the ones of cruising boats, even with the ones of cruising racers.
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Old 05-04-2016, 19:46   #84
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Re: Dutch couple found dead, their sailboat found upturned

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Originally Posted by Panope View Post
I'm short about 100 cubic feet of foam for a buoyant Panope. I could achieve this by sacrificing the lazarette and storage underneath bunks and settees. For my current use of the boat (no live-aboard, no big off-shore trips, etc.), this is feasible.

Steve
That's interesting Steve maybe a watertight lazarette and an airbag or two would be a good compromise? It might also be possible to pump out water and fuel tanks and use them as extra buoyancy, and at least one small boat has made some of the foam cushions out of closed cell foam (or covered in watertight material) to add some extra floatation. Perhaps also a couple of good big inflatable fenders strapped to the outside of the hull for stability...

Anyway, back to Talagoa, certainly in this case with the keel missing and the probable foam insulation plus watertight compartments it would seem possible, even likely that she would float quite well. There has been some speculation about just how watertight a bulkhead can be, and certainly wiring looms, hatches and the like make it hard to completely seal the compartments, but most of these leak points are up high on the bulkhead. The lower sections of the bulkheads are normally only pierced by the bilge pumping pipework, which probably has a closed valve on one end. And with the boat upside down this section would likely trap a considerable amount of air for a long period of time, further enhancing the buoyancy.

So I don't think there is any good reason the boat couldn't have lost its keel and then drifted quite some distance to where it was found, though its also quite possible that something else happened. Too little info at the moment.
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Old 05-04-2016, 19:48   #85
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Re: Dutch couple found dead, their sailboat found upturned

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Originally Posted by Polux View Post
I like your attitude and if I am wrong I will be the first to tell but the link you provide does not work. Please try again, maybe something missed when you posted it.

Sorry. I googled

ISAF keel loss

Seeking to learn from keel failures >> Scuttlebutt Sailing News

That page has links on the bottom of the article. The "details" link brings me to this PDF.

http://www.sailing.org/tools/documen...ailuresdatav2-[17112].pdf

There are other links to discussions and presentations I did not follow.

http://www.sailing.org/tools/documen...5b17113%5d.pdf
Good luck.
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Old 05-04-2016, 20:09   #86
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Re: Dutch couple found dead, their sailboat found upturned

[QUOTE=hpeer;2090401]Sorry. I googled

ISAF keel loss

Seeking to learn from keel failures >> Scuttlebutt Sailing News
<SNIP>[QUOTE]

Very interesting, if slightly sobering reading. Definantly from the list of designers and boat names all (or almost all) of the boats listed under the welded keel failure are high tech racing machines made from foam core with a narrow cord fabricated and welded keel fin, with a bulb attached.

Its actually quite scary how many cases there are, and the list of designers is pretty varied and talented. But as far as I could see, there are no steel or aluminium yachts on that list.
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Old 05-04-2016, 20:12   #87
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Re: Dutch couple found dead, their sailboat found upturned

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Corten steel? It's used because it is more surface corrosion resistant, but there was something about Corten steel in bridge girders in New York (USA) state (they salt the roads in winter) failing unexpectedly after only a few years from a crack form of corrosion (I've forgotten the correct term) in the 1980s. Crack corrosion moves fast.
The steel boat I built was designed by George Sutton, one of the most respected steel boat builder on the East Coast. When picking my plans, I used the opportunity to pick his mind as much I could. For what its worth, he told me not to use Corten Steel. I didn't ask him why, and I wish I did, but whatever Mr. Sutton recommended I did. Tragic loss.
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Old 05-04-2016, 20:19   #88
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Re: Dutch couple found dead, their sailboat found upturned

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Originally Posted by hpeer View Post
Sorry. I googled

ISAF keel loss

Seeking to learn from keel failures >> Scuttlebutt Sailing News

That page has links on the bottom of the article. The "details" link brings me to this PDF.

http://www.sailing.org/tools/documen...ailuresdatav2-[17112].pdf

There are other links to discussions and presentations I did not follow.

http://www.sailing.org/tools/documen...5b17113%5d.pdf
Good luck.
Yes, that was the document I accessed on a more legible version. I had already posted about on a post above (previous post).
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Old 05-04-2016, 20:32   #89
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Re: Dutch couple found dead, their sailboat found upturned

Anything other than an instantaneous failure would give LOUD audible warnings that no sailor would ignore - and these were very experienced sailors.

I know every sound my boat makes and investigate anything the least bit unusual, as I'm sure we all do.

Even if keel plating were to be welded to hull plating with a single circumferential overhead fillet weld as seems to be suggested by Nick, it would have to fail around the whole circumference of the keel in an instant for there to be no warning.

I don't actually believe for one moment that any Dutch yard - or even a home builder - would use such a crazy method of construction.

If the keel is required to be fitted after transport there's no difficulty. One just provides for welding access to the joint from inside the hull. Keel frames would be welded to hull floors/frames as a matter of course. Nobody half-competent would even think of just welding keel plating to hull plating.

Yes, the external weld would likely be 4F but a complete keel relying on one such weld?
The Dutch have been world-renowned for a century as the best builders of small steel boats.

And by the way, I have done more than my fair share of industrial welding

It's my opinion that the keel must, sadly, have been bolted on and that the bolts failed.
When, how and why that may have happened I could only guess.
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Old 05-04-2016, 21:56   #90
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Re: Dutch couple found dead, their sailboat found upturned

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That's interesting Steve maybe a watertight lazarette and an airbag or two would be a good compromise? It might also be possible to pump out water and fuel tanks and use them as extra buoyancy, and at least one small boat has made some of the foam cushions out of closed cell foam (or covered in watertight material) to add some extra floatation. Perhaps also a couple of good big inflatable fenders strapped to the outside of the hull for stability...
Those are good ideas to add buoyancy. However, I might be closer than I think to having positive buoyancy as I find myself always filling nooks and crannies (with foam) every time I do rip-out/rebuild down below. Even last years ice-box project added 6 cubic feet of foam.

If Panope could be made to float no lower than the main deck level, that would leave the pilot house unflooded from the settees up. That would make a decent survival shelter provided the boat was not rolling and plunging like a pig. Gotta be better than a raft. I could even unbolt the mast and send it overboard if it helped.

Any ideas on seakeeping ability of a fully flooded/barely floating monohull (with keel attached)? Seems like it might be fairly stable as long as the water is high enough to not 'slosh'. Sorta like how a FULL water tank is safer than a sloshing one at 1/2 full.

Steve
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