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  #11  
Old 02-02-2005
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Bluewater defined?

When it comes to boats no issue like hull shape and displacement can get disagreements between people.(and just about anything else when it comes to boats)Then ask about bluewater?It is like choosing ones religion,answers come from within.Like Jack said read all you can and find which works for you.Definitions for the most part become interpretations.
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Old 02-02-2005
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Bluewater defined?

Jack, this is a very poor way to exchange views. You missed completely my point and probably that was my fault. Let me try again.

I don’t think the RCD was implemented as a Trade Barrier (there was almost no US sail boats in the EU market, and the situation didn’t change with the RCD). I think that has to do with a global policy (sometimes a true obsession) in ruling everything and giving information to the consumer about everything. This legislative “obsession” has to do mainly with safety and ecology and normally it is a pain in the ass, resulting mainly in a lot of paper work.

Regarding RCD it is the same thing, as you say, manufacturers had certainly influenced the draft in the definition of the categories (and I have said in a previous post that I consider the standards for A class/unlimited inadequately low) and on site compliance visits are mainly a paper work affair.

What is very interesting in the RCD is a small but very important part that escaped to the burocrats and that is Stability. I am not talking about the standards of stability for each class, but in the way it is measured in each boat. This part of the problem was “given” to the British technicians that had a lot of experience in the matter (RYA and RORC) and they have made an outstanding job.

What you have now, is reliable stability information on each model of boat, because they need to have all the data to be classified. I am not talking about classes, I am talking about true and raw information about every aspect of the boat stability (initial, reserve, AVS, GZ, RM curve) that is public and available to you. With this information you can
make your standard and look at the type of boat that suits you.

They have even devised, for the consumers that don’t know what to do with all that data, a smart and relatively accurate way to estimate the global “value” of the boat stability (STIX).

To understand why I say that the stability data is relatively sound you have to consider this:

The process of measuring all the data that permits the evaluation of a boat is not made occasionally in the factory, nor is it made by burocrats. It is a technical work made only one time for each model and part of the measures are taken in the water with inclination tests. Later in the factory, one or two times a year they check the conformity of the production with the test prototype.

Those measurements are not made by the builder but by independent, technical and very specialized private agencies holding a permit given by the EU that attests their independence and competence to do the job. The measures are made according to a very precise set of rules defined by ISO 12217.

I don’t know how things are made there, but it is not believable that one of those agencies would “fake” measures. It would lose its license and be prosecuted. Any obvious fake would be very noticeable to competing brands with similar models.

You seem to think that the builders have a commercial interest in publicizing stability data.

They don’t.

I only know two builders that publicized these data, both uppermarket really ocean going boats with very good stability. Boats with very good stability are very expensive, because mass is part of the equation and it doesn’t make sense to make a very stable boat without making also a very solid one.

Big builders, like Beneteau, Jeaneau, Bavaria never publicize the stability of their boats and you only get stability data if the seller realizes that he will lose a potential client if he doesn’t provide that information.

The RYA has been complaining (without success) for a long time, saying that those figures should be mandatory in the publicity of the boats, as it is in cars for consumption and emissions.

Finally things begin to change because British Sailing Magazines started a policy of only testing a new boat if they have access and can publish the Stix and GZ curve. German magazines seem to go the same way.

Sorry for the long post, but I believe that these data, if accurate, will give everybody a better understanding of the different boats and will help everyone to chose the right boat .

Of course, it is only a part of the picture, but an important one.


Paulo
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Old 02-19-2005
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Bluewater defined?

About the value of STIX as a useful tool to assess a boat stability I have found of interest the opinion that Bob Johnson (president of Island Packet Yacht) wrote in a letter published in the last special issue of Sail Magazine:


...."As the U.S. participant on the international work group of designers and naval architects responsible for developing this particular ISO standard, I''d like to provide some background on its development and shed some light on why I believe it will grow to have considerable value to both the design community and the boat owner."

" As Dave''s article illustrates, the accurate stability assessment of any sailboat is a complex process. Numerous design characteristics influence the ability of any boat to safely resist or recover from capsize, ranging from downflooding openings to the shape of its righting-moment curve. In all, the ISO work group found that seven different calculated factors encompassed all significant stability concerns and, taken together, could establish a single stability index value (STIX) that allows meaningful stability comparisons between various designs."

"The minimum STIX value for each category was created and validated from a study of a large number of existing sailboats, ranging in size and type, that had experienced capsize events, with and without successful recovery. Good correlation was eventually obtained between theory and practice, and the final STIX standard, I think, encompasses all critical stability factors in an analytical method that is based on established principles of naval architecture, sound methodology, and correlates well with real-world experience for real boats. No other single stability-assessment method, to my knowledge, is as comprehensive as STIX. "

...."Lastly, I’d like to comment on the Capsize Screen method mentioned in another sidebar. This was proposed in the 1985 USYRU and SNAME Joint Committee Report on Safety from Capsizing (prompted by the 1979 Fastnet disaster). As Dave correctly states, and I heartily reinforce, by itself the capsize screen evaluation method has virtually no value in the assessment of a yacht''s stability. It''s really addressing a concern that lightweight designs with a wide beam are suspect regarding their susceptibility to capsize, justifying further stability evaluation. One of the seven STIX factors addresses this very issue.


Bob Johnson, President
Island Packet Yachts
Largo, Florida





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Old 06-09-2006
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Another technical resource for this thread

you can find technical theory and a full excel database for "off shore" (which is by some measures the meaning of "blue water" at http://www.johnsboatstuff.com/technica.htm

of course, if my boat wasn't listed I wouldn't recommend it .
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Old 06-09-2006
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Can anyone point me to a URL listing various boats and their STIX ratings, so I can get an idea of which rates for what?
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Old 06-10-2006
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I doubt anyone has the STIX ratings published, as much will depend on how you have the boat loaded and rigged, and where you have supplies and equipment stowed.
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  #17  
Old 06-11-2006
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I beleive that the actual ratings for individual designs are available though the CE Certification body, but I think that there is a fee for each boat certificate requested.

Jeff
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Old 07-25-2006
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I'm just getting my thoughts together in the sail mode after several years in the powerboat "thing"... certainly there must be somebody that agrees on something....while I'm getting a late start...I'd like to find a nice boat that can be sailed with two or single handed...in the Gulf...and Carib...I'm 65....with all of the STIX, AVS and RCD's....whew...can get confusing....displacement, length....
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Old 09-12-2006
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Cheers everybody!
There is also an interesting discussion on these matters at:
http://boatdesign.net/forums/showthread.php?t=13569

From there (Some small parts of text have been changed, not to repeat everything posted there):

Well, thinking CE marking is not conceived for racing boats, but for the recreational market, where most of cruising boats are short handed and boats should look after their crews, in my humble opinion, I think it's worrying that some boats can be labelled as Category A, taking into consideration they have what has been commonly understood for many years, among designers, NA’s and boat owners, as 'cruel' and even dangerous ratios and parameters. Those boats are too stiff by all means, with a low motion comfort ratio, too high accelerations (And so quite punishing for a short handed crew) and with Capsize Safety Factor well above 2, widespread considered a safe limit.

In my opinion STIX provides not enough information about the seaworthiness of a boat (It was never intended to be a clue to this, but this idea is spreading around quickly) and may even be a tricky and dangerous number. Seaworthiness is a complex matter, involving stability, all around scantlings, quality of movements, and a long etc.

I think manufacturers/designers should at least be obliged to publicize the STIX Factors and not only the number itself (Which is not even mandatory!). And even better, publish also the 'old' ratios and parameters, for the people to have a more complete view and understanding of the boat.

Rolf Eliasson (One of the fathers of the STIX number) himself expressed some serious concerns about the STIX number and how it finally 'came to life', in the aforementioned article. He even suggested minimum STIX for Categories A and B should be 40 and 28, instead of 32 and 23 as it is now. But even rising the level provides not enough guarantee as to define a boat as seaworthy, as we could see per numbers above.

Again in my opinion, most probably a great pressure from modern mass (and light) boats producers (and their designers) was put into the process. Those manufacturers produce very nice boats for Club racing and coastal cruising in fair weather (what most of users do) and fun to sail, but of course they want not many of their models to be obliged to be labelled as Category C, what they should be in most cases.

Long range racing is quite a different thing (with full trained crews aboard), than family oceans crossings so, in my opinion, CE Category's assigning criteria should be revised and adequate to the RCD’s own reason of existing. If racing is intended, a new special Category or Note should apply in addition to the ‘familiy’ Category.
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Old 01-05-2007
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Sailing dog:

“I doubt anyone has the STIX ratings published, as much will depend on how you have the boat loaded and rigged, and where you have supplies and equipment stowed”.

Hellosailor:

"Can anyone point me to a URL listing various boats and their STIX ratings, so I can get an idea of which rates for what?"

PCP:

Sorry for taking so long in repling, but I don’t have been around this Forum.

The stix doesn’t change that much with the boat loaded, unless you load it over the Maximum load capacity. Anyway now they have to show the calculations for two STIXs, One in the minimum loading displacement and the other in the Max loading displacement. Normally the difference is not bigger than 1 point.

I will post my opinion about the STIX, as posted in another boatforum and some others more relevant as well as a short list with sailboat’s STIXs.


STIX:

STIX it is an evaluation for an existing Yacht about its stability and seaworthiness. It is intended not for professional, but for the common user, just to give him a correct idea of the seaworthiness of a given boat.

It is in that sense that RYA says that: “just the same way it is mandatory for the fuel consumption of all new cars to be published…that stability information should also be available to a buyer of a boat”.

STIX is only an easily understandable index (but found through a complicated calculation that takes into account a lot of different stability factors) that is in my opinion, the most sophisticated stability screening tool available.

Certainly very superior to the old Stability Indexes, that in many cases were very misleading and were not unified. I mean, you needed to take a look at several to have an idea of the boat, and many times a wrong idea, mainly with modern deep drafted bulbed yachts.

Don’t get me wrong, it is not a perfect tool, (only the best until now).

Personally I take a look at the STIX for having a general idea, but my evaluation is done independently by the analysis of the RM curve and done by a close examination of the boat (and I mean not a virtual one), with answers about the way it is built and the kind of materials that are used. Special incidence in the way the keel is fixed to the boat, about the rudder and about the hatches and all the “glass” surfaces and the way they are secured to the boat. Not that these are the only important points, but if special care is taken with these ones, there is a good possibility that all the others are well taken care of.

But for understanding a RM curve correctly you have to know a lot more.

STIX is just a number and its interpretation could not be simpler: The bigger, the better.


The RYA view about STIX:

“STIX is arguably the most sophisticated stability screening tool yet available. ….
Since June 1998 all new recreational boats sold in the EU have been required by law (the RCD*) to have undergone a stability assessment with the preferred method being the application of ISO 12217. “


http://www.rya.org.uk/NR/rdonlyres/43D83922-ED3E-4D5D-BBCF-6A14AA352EFA/0/StabilityIntro.pdf#search=%22stabilityintro%20pdf% 22

The Paul Miller view (D. Engr., from the Dept. of Naval Architecture of the United States Naval Academy:


“The Best we have…”


Bob Johnson view: (Naval architect, the Island Packets designer and the U.S. participant on the international work group of designers and naval architects responsible for developing STIX):

… STIX standard, I think, encompasses all critical stability factors in an analytical method that is based on established principles of naval architecture, sound methodology, and correlates well with real-world experience for real boats. No other single stability-assessment method, to my knowledge, is as comprehensive as STIX.

BENETEAU 50 AVS 109 STIX 41

BAVARIA 42 STIX 36

BENETEAU 50 STIX 41

BENETEAU 57 STIX 53

CATALINA 34 MK11 STIX 36

CATALINA 42 40 AVS 105

COMET 36 STIX 32.5 AVS 127

CONTESSA 32 STIX 33 AVS 155

CYCLADES 39 STIX 38 AVS 126

CYCLADES 43 STIX 36 AVS 121

DISCOVERY 55 STIX 37 AVS 122

ELAN 37 STIX 40 AVS 136

ELAN 40 STIX 37 AVS 128

ELAN 44 STIX AVS 124

ETAP 32 STIX 36 AVS 122

ETAP 34 STIX 37 AVS 123

ETAP 37 STIX 42 AVS 123

FIRST 36.7 STIX 34 AVS 126

FIRST 40.7 STIX 37 AVS 126

FIRST 42.7 STIX 35 AVS 118

FIRST 44.7 STIX 41 AVS 130

FIRST 47.7 STIX 46 AVS 123

FISHER 34 STIX 33 AVS 180

FISHER 37 STIX 43 AVS 180

HANSE 371 STIX 35 AVS 122

HANSE 411 STIX 33 AVS 128

HANSE 461 STIX 35

HANSE 531 STIX 39

HARLEY REFLEX 38 STIX 41 AVS 143

HOD 35 STIX 41 AVS 140

HUNTER CHANNEL 31 (single keel) STIX 32 AVS 130

HUNTER CHANNEL 31 (twin keel) STIX 33 AVS 130

HUNTER CHANNEL 323 STIX 35 AVS 149

ISLAND PACKET 350 STIX 49 AVS 141

ISLAND PACKET 370 STIX 43

ISLAND PACKET 380 STIX 55 AVS 136

ISLAND PACKET 420 STIX 59 AVS 136

ISLAND PACKET 440 STIX 48 AVS 133

ISLAND PACKET 445 STIX 53 AVS 141

ISLAND PACKET 485 STIX 66 AVS 143

J12O STIX 43 AVS 127

J100 STIX 37 AVS 126

J125 STIX 42 AVS 131

J133 STIX 46 AVS 130

J145 STIX 52 AVS 139

J160 STIX 57 AVS 118

J42 STIX 45

J46 STIX 48 AVS 127

MALO 45 STIX 62

MISTERY 35 STIX 32 AVS 156

NAJAD 380 STIX 43 AVS 128

OCEANIS 343 STIX 34 AVS 134

OCEANIS 351 STIX 35 AVS 125

OCEANIS 361 STIX 32 AVS 120

OCEANIS 36CC STIX 35 AVS 126

OCEANIS 373 STIX 36 AVS 132

OCEANIS 381 STIX 38 AVS 130

OCEANIS 393 STIX 43

OCEANIS 411 STIX 37 AVS 114

OCEANIS 423 STIX 38 AVS 119

OCEANIS 44CC STIX 34 AVS 110

OCEANIS 461 STIX 37 AVS 115

OCEANIS 473 STIX 48 AVS 119

OCEANIS 523 STIX 46 AVS 111

OCEANIS 42CC STIX 38 AVS 38

SEAQUEST 32 STIX 37 AVS 132

SEAQUEST 36 STIX 46 AVS 142

SEAQUEST PRIMA 38 STIX 52 AVS 131

SOUTHERLY 110 STIX 55 AVS 151

SOUTHERLY 115 STIX 51 AVS 150

SOUTHERLY 35RS STIX 37 AVS 160

SOUTHERLY 135 STIX 54 AVS 139

SUN ODYSSEY 37 STIX 33

SUN ODYSSEY 39i STIX 33

SUN ODYSSEY 40DS STIX 37/39

SUN ODYSSEY 40.3 STIX 36/38

SUN ODYSSEY 43/43DS STIX 44

SUN ODYSSEY 52.2 STIX 50

SUNFAST 35 STIX 33 AVS 127

SUNFAST 37 STIX 32

SWAN 40 STIX 36 AVS 112

SWAN 44 STIX 38 AVS 123

SWAN 45 STIX 57 AVS 134

SWAN 46 STIX 53 AVS 128

SWAN 48 CR/R STIX 49 AVS 135

SWAN 56 R STIX 50 AVS 127

SWAN 56 R/C STIX 55 AVS 124

SWAN 57 RS STIX 53 AVS 132

SWAN 60 R STIX 68 AVS 128

SWAN 60 R/C STIX 70 AVS 122

SWAN 601 STIX 84 AVS 153

SWAN 62 STIX 63 AVS 122

SWAN 68 R STIX 76 AVS 127

SWAN 70 STIX 82 AVS 133

SWAN 75 R STIX 81 AVS 121

SWAN 80 R STIX 80 AVS 138

SWAN 82 R STIX 88 AVS 127

VANCOUVER 28 STIX 36 AVS 170

VANCOUVER 34P STIX 35 AVS 166

VANCOUVER 34C STIX 36 AVS 139

WARRIOR 40 STIX 47 AVS 133

WESTERLY OCEAN 43 STIX 40 AVS 129

X YACHTS 37 STIX 35 AVS 123

X YACHTS 40 STIX 37 AVS 113

X YACHTS IMX 40 STIX 47 AVS 132

X YACHTS 43 STIX 40 AVS 119

X YACHT IMX 45 STIX 46 AVS 124

X YACHT 46 STIX 44 AVS 123

X YACHT 562 STIX 57 AVS 122

X YACHT 612 STIX 51 AVS 110

X YACHT 70 STIX 73 AVS 126

X YACHT 73 STIX 84 AVS 121

Last edited by PCP; 01-05-2007 at 12:26 PM.
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