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post #120 of Old 12-31-2013
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Re: Wow... Bernard Stamm's Open 60 "breaks in half" in the Western Approaches...

Originally Posted by zz4gta View Post
PCP - NA's are still having trouble estimating the dynamic loads on offshore sailboats (hence the change from 4:1 to 5:1). You listed a well published safety factor.
It is not a published factor but a mandatory one. All boats have to have at least that safety coefficient.

Originally Posted by zz4gta View Post
But I'm pretty sure the rest of the boat is not built to a 4:1 safety factor. You're very good at picking and choosing snippets of information that support your argument.
That is an unfounded statement. I do not find snippets of information, I found my opinions. The only one available is that one, the others are obviously a well kept secret.

There is a good reason for that one to be a mandatory coefficient and not any other and the reason is that the keels have been by far the most fragile part of that boat (with the masts). That is why there are a mandatory safety coefficient for keels and not for any other boat part. Hulls have been particularly resistant and did not show any particular weakness being Stamm’s case an exception in many years in what regards a catastrophic breakage.

Originally Posted by zz4gta View Post
Race boats have always been lightly built unless they're under a rating system that gives heavy boats an advantage, like MORC. …
Of course, but contrary to other offshore racers these boats are designed to race a non stop circumnavigation sailed most of the time in high latitudes. If they don’t finish they don’t win.

This is not the kind of offshore boat that makes a Fastnet or a Sydney-Hobart and then are thoroughly verified to see if all is alright or if something needs fixing. On these ones that only happens after a 40 000nm circumnavigation and for that reason they have to be much stronger than the typical offshore carbon racer. That has a reflex in what regards the applied safety coefficient, that is naturally bigger than on racers that race incomparably shorter races, even if offshore ones.

Originally Posted by zz4gta View Post
What you chose to not address what my point about item #4: This boat should not have broke. PERIOD. It was well under powered in the conditions and was either an oversight of the sailors (very likely on a delivery where everyone is not 'dialed in') or it was a build issue/ inspection issue. ……

Item #4: None of this has anything to do with what happened in this incident b/c the boat wasn’t powered up or racing. Heavily reefed on a delivery it got caught in a storm and thankfully no one died. This boat (not the open 60 platform) clearly had some structural issues that weren’t caught on its last inspection and the damn front tried to fall off.
That one I do not understand. You have answered yourself that question: “This boat (not the open 60 platform) clearly had some structural issues that weren’t caught on its last inspection”. Probably Jon is right and that previous delamination (hole) that boat suffered produced structural problems that were not detected neither repaired even if the boat made 60 or 70 000nm after that.

Originally Posted by zz4gta View Post
Let me make it clear, I'm not hear to say that open 60's are unsafe boats, but they don't hold the same safety factors as a Hanse or Hinckley. This is an acceptable risk as I see it. However, you cannot say that carbon race boats don't have failures on a pretty regular basis. And part of this is due to the thin layup, and lack of historical data in regards to cyclical loads on a rough sea. They're still working out the details.
In fact carbon boats can be much stronger than boats built with any other materials and the failures on carbon racers have nothing to do with the material itself but with the fact (as you say) that they are built as light as possible.

There are cruising boats built in carbon and there will be more in the future.

The technology exist for many years and is used not only in boats but cars and airplanes. The details have long been worked….not yet completely in what regards the loads in a canting keel, but that is a different story and that were mostly of steel (and now they are all).

Regarding the reliability of carbon hulls, there are many old Open 60 with 15 years still racing around the world. In fact they have proved so “indestructible” that they are used on a minor circumnavigating race, the Velux 5 Oceans (minor but longer). Each of those boats had already made many circumnavigations and hundreds of thousands of Nm, more than almost any cruising boat on the planet and they have made them racing and many times in high latitudes.

The fragility of carbon racers has to do with being as light as possible regarding the conditions they meet. Inshore carbon racers are more fragile than offshore carbon racers and these ones more fragile than boats designed to race while circumnavigating non stop. This ones have to be necessarily very strong.

Yes, it is possible that a Hinckley or an Hanse have a safety coefficient bigger but that coefficient is related with the forces and conditions the boat have to face and as a IMOCA boat has to face much tougher conditions that does not mean that a Hanse or a Hincley are stronger than an Open 60, quite the contrary. Put them on the big Austral desert facing 50K winds and 10 meters waves and they are more at risk than an Open 60, from breakage and from capsizing, simply because the Open 60 was designed taking those conditions into consideration, not the Hanse or the Hinkley.

That does not mean that I do not agree with you that these boats are so powerful that they cannot be sailed full throttle all the time. The shipper has to manage the power according with the sea conditions but for what we have seen on the last edition…the power these boats can take even in rough conditions is just amazing. In fact I am no sure who would break first, the boat or the skipper.

well, here is already 2014. For the ones that are still in 2013, a good "passage". I am drinking champagne!!!



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Last edited by PCP; 12-31-2013 at 09:37 PM.
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