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Old 07-10-2014, 01:10 AM   #121
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One thing to remember with "classed" vessels, there are classes within the classification body. So a vessel can be "classed" but perhaps only with in a narrow set of criteria. Say classed for operating no more than X amount of miles offshore. And some classification agencies are know to be a bit more lenient than others. As are some agencies inspectors.
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Old 07-10-2014, 01:46 AM   #122
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Fifty-foot waves, so what's the big deal? A good photo opportunity. One just needs to be in a capable vessel.

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Old 07-10-2014, 02:03 AM   #123
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One thing to remember with "classed" vessels, there are classes within the classification body. So a vessel can be "classed" but perhaps only with in a narrow set of criteria. Say classed for operating no more than X amount of miles offshore. And some classification agencies are know to be a bit more lenient than others. As are some agencies inspectors.
True. Whether classed or insured or regulated, this boat hadn't reached the point where any of them would have been doing stability testing. Now, perhaps some review of design in advance would be a different thing. But then in this case there would appear to have been many precautions that perhaps could have been taken but weren't.

There are also other tricks of deception some builders use. I quote from an article on Nordhavn's site as to what one builder wrote:

Their boats “are certified by ABS and Lloyd’s Register and have achieved the Bureau Veritas ‘unrestricted navigation’ category. This means they also carry a CE Category A ‘ocean’ rating and meet NMMA/ABYC standards.” What?!? ABS is very clear that it doesn’t “certify” boats and does not even look at boats smaller than 79 feet, CE is only for boats going to Europe, and NMMA is not a part of ABYC. We’ve asked magazine editors to be on the lookout for such loose mention of these standards organizations.

I've read "Built to unrestricted classification standards" or similar. Incidentally Nordhavn has built many 86's to class and estimates the added cost at $300,000.

I recommend whether classification or otherwise having someone independent helping to oversee the process. Of course, the best protection ultimately is the quality of the builder.
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Old 07-10-2014, 08:49 AM   #124
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Look at a Forida Bay Coaster (style) or the "Ferry" class houseboats by Jay Benford....
Exactly.

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Old 07-10-2014, 01:36 PM   #125
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Thanks Tad.

To what degree does the 10 page Roddan study represent the kind of detail needed? Also, do you find the fact that the maximum stable heel angle even if ballasted as recommended is only 65 degrees as shown in appendix 4 to be worrisome? Seems like there would be a lot of conditions I could imagine her being exposed to as the 'Ultimate World Cruiser' that might result in a greater heel angle.
First of all I have no interest in criticizing anyone, I am interested in the problem and in helping people understand what happened.

To the degree that it was a snapshot 10 months prior to launch the Roddan report is fine. In my office such a report represents a file folder full of paper, which we have no access to. So the report represents a great deal we do not know.

From the report it's evident that transverse (Y) weights were not being tracked very seriously. That's not unusual. The boat was heavy on the portside, how much in reality? We don't know. A typical full weight study for a vessel of this size will run to 30 pages of data, that's not here.

Another problem is how much of the boat was included in the stability calculations (this applies to your question on adequate stability). The amount of superstructure included will make a big difference.

If you look at the Roddan report page 7, at the bottom there are some criteria and pass/fail is indicated. The standard (CFR.....) is only concerned with adequate stability up to 40 degrees heel. This CFR standard is an adoption of the same IMO standard that most of the world uses for small commercial vessels.

Years ago I did a simple stability study of a Nordhavn (55' I think) and a Diesel Duck. This was just for my own curiosity. I concluded that both boats ran out of stability at something below 80 degrees heel. So 65 does not surprise me. Again it would not be my choice given the intended use, but that's a personal issue.
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Old 07-10-2014, 01:57 PM   #126
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First of all I have no interest in criticizing anyone, I am interested in the problem and in helping people understand what happened.

To the degree that it was a snapshot 10 months prior to launch the Roddan report is fine. In my office such a report represents a file folder full of paper, which we have no access to. So the report represents a great deal we do not know.

From the report it's evident that transverse (Y) weights were not being tracked very seriously. That's not unusual. The boat was heavy on the portside, how much in reality? We don't know. A typical full weight study for a vessel of this size will run to 30 pages of data, that's not here.

Another problem is how much of the boat was included in the stability calculations (this applies to your question on adequate stability). The amount of superstructure included will make a big difference.

If you look at the Roddan report page 7, at the bottom there are some criteria and pass/fail is indicated. The standard (CFR.....) is only concerned with adequate stability up to 40 degrees heel. This CFR standard is an adoption of the same IMO standard that most of the world uses for small commercial vessels.

Years ago I did a simple stability study of a Nordhavn (55' I think) and a Diesel Duck. This was just for my own curiosity. I concluded that both boats ran out of stability at something below 80 degrees heel. So 65 does not surprise me. Again it would not be my choice given the intended use, but that's a personal issue.
Much appreciated. Wouldn't be my first choice either, but I just wasn't sure what was considered appropriate for someone who wants to cross oceans. 65 degrees seemed a bit skinny, but as you say, perhaps that is a personal preference based on a bit of blue water sailing and seeing some pretty big waves. I have no idea what Delfin's stability is, but believe there is more weight below the water line than above so I assume it is fine.
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Old 07-10-2014, 02:12 PM   #127
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As to stability standards, I would certainly imagine they were required by the insurer in this case.
I've never seen or heard of this in the US, have you? Insurers require proof of crew competence and a current survey, which never mentions stability. They may offer a discount if the vessel is "In Class", that's designed and built under survey and surveyed in the last 2 years. Or they may offer a small discount if there's a "Hull Certificate". A hull certificate just states the hull (structure only not machinery) was designed and built to a certain standard.


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Also, if I was building a 90' boat for ocean travel, I'd require it being classed and that would include stability standards and require stability testing.
I agree that would be a good idea and in the owner's best interests. But it's very unusual in the US while pretty much standard practice in Northern Europe. It does add considerable to the cost of the vessel.

Classification societies in general do not impose stability standards. That is done by the flag state. Thus the Roddan report on Baden refers to CFR....., (Code of Federal Regulations). In Canada we have stability standards set out by Transport Canada, in Britain it's the MCA (Maritime and Coastguard Agency). In the US there is no legal stability standard for pleasure craft of this size.

[/QUOTE]
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Old 07-10-2014, 02:12 PM   #128
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And that in the straits. My point is simply that you could probably imagine a roll of 50 degrees in inland waters since you've experienced it, so you probably wouldn't be shocked to hear that vessels get knocked down in the ocean. I mean, really? The most recent loss I am aware of is a British sailing vessel that went down in 20 foot seas on their way home from the Caribbean. Like I said, stuff happens.

4 British sailors missing at sea after yacht believed to have capsized in mid-Atlantic | Mail Online
This boat capsized becaust the keel fell off. If the keel had stayed put, that vessel could theoretically get knocked down all day and still return to an upright position.
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Old 07-10-2014, 02:30 PM   #129
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Much appreciated. Wouldn't be my first choice either, but I just wasn't sure what was considered appropriate for someone who wants to cross oceans. 65 degrees seemed a bit skinny, but as you say, perhaps that is a personal preference based on a bit of blue water sailing and seeing some pretty big waves. I have no idea what Delfin's stability is, but believe there is more weight below the water line than above so I assume it is fine.
This is what I mean when I wrote that stability is not intuitive. You can spend a great deal of time on a vessel and still not know her angle of vanishing stability.

Reality is that it's not a big issue. So far (and I have looked) I've not found one accident report where a pleasure craft being properly operated capsized due to normal sea conditions. Crossing a bar, going too fast, hitting something, or being subject to overloading or flooding are all the usual causes.

Another thing is that usually Naval Architects build in a margin of error. Often stability studies include just the hull. But reality is that the deckhouse will modify the stability curve and bump the ultimate stability up, in some cases quite a bit. Of course that's dependent on the house (windows) staying intact and not too much stuff inside falling onto the low side. Thus do theories go awry.....
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Old 07-10-2014, 02:51 PM   #130
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I for one would just like to raise a glass to Tad for the wealth of expertise he brings to this forum . . . and for the civility he brings to discussions that might otherwise turn into pi$$ing contests. Thanks!

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Old 07-10-2014, 02:55 PM   #131
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This boat capsized becaust the keel fell off. If the keel had stayed put, that vessel could theoretically get knocked down all day and still return to an upright position.
Ah, I didn't see that report. Thank you.
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Old 07-10-2014, 02:59 PM   #132
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I've never seen or heard of this in the US, have you? Insurers require proof of crew competence and a current survey, which never mentions stability. They may offer a discount if the vessel is "In Class", that's designed and built under survey and surveyed in the last 2 years. Or they may offer a small discount if there's a "Hull Certificate". A hull certificate just states the hull (structure only not machinery) was designed and built to a certain standard.

I agree that would be a good idea and in the owner's best interests. But it's very unusual in the US while pretty much standard practice in Northern Europe. It does add considerable to the cost of the vessel.
[/QUOTE]

I think it's unusual in the US up to a certain size. I would think more common on a 90', but does depend on who the insurer is. Very few US builds classed. Mostly over 125'.

As to the discounts for class, survey, stability etc. would take a long time to pay for the additional costs. We've found if you do everything perfectly as they desire you may save 10%.
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Old 07-10-2014, 03:01 PM   #133
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I for one would just like to raise a glass to Tad for the wealth of expertise he brings to this forum . . . and for the civility he brings to discussions that might otherwise turn into pi$$ing contests. Thanks!

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Old 07-10-2014, 03:29 PM   #134
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...
Years ago I did a simple stability study of a Nordhavn (55' I think) and a Diesel Duck. This was just for my own curiosity. I concluded that both boats ran out of stability at something below 80 degrees heel. So 65 does not surprise me. Again it would not be my choice given the intended use, but that's a personal issue.
Do you remember which Diesel Duck model you studied?

Thanks,
Dan
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Old 07-10-2014, 04:09 PM   #135
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Much appreciated. Wouldn't be my first choice either, but I just wasn't sure what was considered appropriate for someone who wants to cross oceans. 65 degrees seemed a bit skinny, but as you say, perhaps that is a personal preference based on a bit of blue water sailing and seeing some pretty big waves. I have no idea what Delfin's stability is, but believe there is more weight below the water line than above so I assume it is fine.
So in the end it looks like if you careful, properly prepared, pick your weather and perhaps have a little luck as well, a vessel with "only" 65 degrees of stability could cross an ocean or two on its own bottom.
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Old 07-10-2014, 04:34 PM   #136
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So in the end it looks like if you careful, properly prepared, pick your weather and perhaps have a little luck as well, a vessel with "only" 65 degrees of stability could cross an ocean or two on its own bottom.
Yeah. But don't try to launch the thing.
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Old 07-10-2014, 04:41 PM   #137
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I think it's unusual in the US up to a certain size. I would think more common on a 90', but does depend on who the insurer is. Very few US builds classed. Mostly over 125'.

As to the discounts for class, survey, stability etc. would take a long time to pay for the additional costs. We've found if you do everything perfectly as they desire you may save 10%.[/QUOTE]

I agree. In my experience classed vessels under 120' or so are pretty rare. And as you noted any savings in insurance are off set by costs to meet class standards and then the costs of staying in class as the years go by.

Like periodically having to pull out every sea cock on the boat at the time of haul out and set them all up on a bench so the class surveyor can see that they all are in good working order. Stuff like that can jack your yard bill up real quick. Even if the boats engineer and crew pitch in to do a lot of the work.
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Old 07-10-2014, 04:44 PM   #138
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Yeah. But don't try to launch the thing.
Well, I did mention being properly prepared.
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Old 07-10-2014, 05:09 PM   #139
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It was the 462 DD. I enclose the computer models and righting arm curves below. These were done in 2008 only for myself. They are not in any way intended to be taken as critical of the builders. They are based on certain assumptions by me, and they will not hold up in a court of law...

At the time Steve Dashew had made some disparaging remarks about the stability of powerboats. I tried to find a problem and it turned out there isn’t one. These curves do illustrate the general stability characteristics of these type of hulls. Note that I have included the aft raised deck on the DD and the raised foredeck on the Nordhavn. The VCG's shown are above the indicated waterline, LCG is at wherever the LCB was at that floatation.

Both these boats show vanishing stability angles of about 85 degrees. That will change if more of the house was included, or if the loading (fuel and water mainly) and floatation changed.


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Old 07-10-2014, 05:55 PM   #140
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Yeah. But don't try to launch the thing.
Which is why this thread has gone to 7 pages.

Not many of us, under any circumstances, can see spending any money, let alone big bucks, on a boat that add it is launched, a 30% list gets it to turn turtle.

It's funny to me, but also to me days a lot about the builder. NO MATTER WHAT THE CIRCUMSTANCES.

Because I'm sure this mishap report will detail the separate things that added up to this loss, but ultimately, I don't want a boat that can't be launched with no room for error.
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