Sailing boats' Stability, STIX and Old Ratios

I am afraid that without the blues and reds, what you have posted is not clear.

If someone wants to have a look at it, it is here:

http://www.boatdesign.net/forums/showthread.php?t=20154&page=5

But I don’t understand you. Architects can not make mistakes? Neither one as simple as switching (by mistake) a previously posted number (by me) by another number (the one that Guillermo had calculated)?

If you keep looking to that thread you are going to see that all the rest is correct, I mean the explanation on the divergence between the two AVSs and the two STIXs, and that is the important part. There is a big difference between a mistake and an error.


Do you care to explain exactly what you are talking about when referring to basic mistakes?


You are not talking of post 250 of this thread, are you?


I don’t understand also why you keep posting on this thread things that have nothing to do with it, I mean like this one:

I did not know that Guillermo worked with big racing High-Tec boats.

Anyway I will post your comments on the proper thread, the thread from where you have taken these posts. Perhaps some of the guys that post there or that know and are interested in racing boats can comment on your ideas.

By the way, do you really think that the performance of the Groupama racing trimaran has something to do with the performance of the Gunboat 66 cruising cat?

 

Quote Guillermo:
"Intellegis Pericles esse philosophum?" Tum kwb1312 nimium mordaciter: "Intellexeram", inquit, "si tacuisses"

Qualis autem homo ipse esset, talem esse eius orationem

 

Guillermo,

Are philosophers understanding? It is kind that you felt that kwb1312 was biting when he quoted Boethius "If you had been silent, you would have remained a philosopher" to which I reply "Quid quid latine dictum sit, altum viditur, atque memento nulli Romanorum qui locutionem tuam corrigant".

kwb1312,

Marcus Tullius Cicero?

Qualis autem homo ipse esset, talem esse eius orationem

At the speech, do you recognise the man?

To whom do you refer?

Pericles

 

kwb1312

I must agree that politicians, American, French, British, are bottom feeders in the gene pool. That much is true. From reading about the history of Brittany it would seem the people there have much more in common with Britain than with France.

After the withdrawal of Roman troops in the reign of the emperor Honorius,the Romano-British were forced to fight for themselves but quickly developed their own armies among hiring barbarians from across the Sea. Romano-British were divided politically as former soldiers,nobles and officials declared themselves kings fighting amongst each other allowing later peoples to take Britain. The depredations of the Picts from the north and Scotti (Scots) from Ireland forced them to seek help from pagan Germanic tribes of Angles, Saxons and Jutes, who decided to settle. However, the Germanic tribes became hostile against their hosts and began to conquer their territory. Romano-British culture, over the course of six centuries, was restricted to the western fringes of the island in Wales, Devon and Cornwall and the north in Strathclyde, Cumbria and Elmet. Some of the Romano-British may have migrated to Brittany and possibly Ireland.

http://en.wikipedia.org/wiki/Romano-British

Pericles

 

Pericles,

Not biting, just mild irony. I don´t think we disagree in the matter, but throwing Shakespeare, Oscar Wilde and „the American nation“ in one pot asked for some reply. - For the sake of argument.

Re. Qualis autem..... it was my direct reply to Guillermo´s „Intellegis Pericles esse philisophum“, and ref. to your sentence „....and I came face to face with you, I would not be so patient as Guillermo and you would be holding your teeth on your hands.“

As to Mr. Sykes: I do not know how correct his results are, as depending on e.g. the number of markers you might get quite different results. But even if we assume he is right without any if´s and but´s, so what Pericles? Were you afraid that the „politically-correct elites“ (Quote P.) are right? Don´t worry, they are not. And despite what our constitution says neither science nor speach is free. But here we are more than only „slightly off topic“ and we better return to Stix and MOC (especially MOC )

 

Agreed. It was mordacity.

An interesting diversion, nevertheless. You had me working for a while.

Pericles

 

Interesting to review some of Vega's interesting opinions at the “Keels and Keels again” thread:

I cannot less than strongly agree with him.
(But then I feel somewhat confused comparing this with some of his statements in several of his recent posts at this and other threads.....)

Cheers.

 

Putting your quote on context:

I have posted this almost two years ago. As you can see I thought much like you, in what concerns modern boats and cruising.

I learn fast and I change my views accordingly. All the data that I have received along these two years have changed my judgment on many things.

So, I would say, sorry PAR, you were right and I was wrong .

On the last two years I have looked closely to a lot of boats. I want to have a bigger one and I have contacted a lot of manufacturers that have boats that for a reason or other, interest me. Most of the time I have received all the information I wanted (about stability and about structural integrity), many times from the technical department and sometimes I have been invited to visit the factory and see by myself how things were done.

During this time I had the opportunity to compare stability curves of typical big production cruisers from 15 or 20 years ago with stability curves of big production typical modern cruisers.

The modern ones are better. The boats are stiffer, can carry more sail and have a better AVS. The boats are lighter, but modern materials make them as strong and stiffer.

About the European certification and Class A boats, well, they were right and I was wrong. I have said that Class A boats should have at least a 40 Stix. Nonsense, I believe that the knowledgeable technicians that have made ISO 12215 knew what they were doing and I believe that the last modification, introducing the need to take into account the boat stability data on Max Load Condition, was a further step on the right way.

I also believe that I was wrong in assuming that an expensive 40ft boat, like de Halberg-Rassy, was more seaworthy than a big production 49ft, like the Jeanneau. Their stability curves say otherwise and if not as luxurious, the Jeanneau is a strong boat, and certainly an offshore boat.

Yes, I have learned and I have changed. When are you going to change ?

I will post the picture of a boat that I was designing when I have posted that (two years ago). It was what I considered then, as the boat I wanted for cruising ( I remember you liked the boat).

I will post also a drawing of another boat, one that I began drawing when I understood that the first drawing didn’t represent the boat I wanted anymore (too heavy and too slow).

I have abandoned that too. I will modify a lot of things. Not fast enough, not stiff enough.

The differences between those two boats are in consonance with the differences between what I thought two years ago and what I thought some months ago.

Cheers

 

You openly admit now you had no idea two years ago. What makes you think you have learnt something? And why on earth do you think we have to believe you now? I think the problem is you have not enough technical knowledge and you change opinions with the wind, as I've told you before. I just think you didn't know why you were saying what you were saying two years ago, and you still do not know why you are saying what you are saying now.

I know you think professionals here who do not share your point of view are stupid by not changing their ideas so easily, but I'm afraid you're just moving with fashion and marketing. That easy changing of opinions precisely reflects your lack of knowledge. And that lack of knowledge (and your extraordinary big ego!) makes you think you know something. But you still know 'nada de nada' on these matters, my friend. In my humble and stupid opinion, of course.

Yes, I believe you when you say you have review a lot of boats and info from many manufacturers, your efforts are laudable, but I'm afraid that what you have now is just a big 'diarrhea' in your head. You have not properly digested yet the received info, as it is thoroughly reflected in your posts and statements.

As far as I know you have never performed an stability test and calculation in your life, neither an structural one, but you dare to scorn professionals here, who have done that for years and who have no interest in selling you a boat, just trying to contribute to these forums with their experience.

On top of all that you distort reality and other people's words to try to support what you're saying, as you do with PAR here. And what is worst, you do award yourself things other people have said, like the STIX 40 thing, who was not said by you, but by Rolf Eliasson (one of those knowledgeable technicians you mention) and posted by me (As it was with the needing of taking also into account the data in the MLC condition to assess STIX if MLC>1.15*MOC. You had no idea of that. Just review this STIX thread.)

By the way, what has ISO 12215 has to see with STIX?
Have you finally got your own copy of relevant ISO norms?
Have you studied already some basic books? Which ones?

You're not trying to learn from the people who know more than you. You're just trying to demonstrate you're the smarter guy, in spite of your lack of formation and experience, which I find annoying and unfruitful.

Finally, let me quote here Pericles the Great , who did a good radiography of your posts, some of us here do share:

(But I don't share his 'teeth' thing... )

Cheers.

 

May we know the main dimensions, displacement, ballast, sail area, GZ curves, prismatic coefficient, wetted area, polars, intended material and structure, etc, etc, for the two boats, so we can better understand you? Also knowing your briefing agenda for the design would be of great help. Thanks in advance.

Cheers.

 

Okey!
What I found from Guillermo's replies here:

6.2.1.1 The requirements given below, and in 6.2.2 and 6.2.3, shall apply to all downflooding openings, except:
a) watertight recesses with a combined volume less than LhBhFm/40, or quick draining recesses.

and

Φda1 is the angle of heel at which openings which are not capable of closure to tightness degree 3 of ISO 12216 having a combined total area, expressed in square millimiters (mm2), greater than the number represented by (50Lh^2) first become inmersed."

So a for a boat of Lh=12 m, all openings greater than 7200 mm2 (0.0072 m2), which's closuring device (If any) doesn't comply with required tightness degree, shall be checked for this.

Those are small openings, not big. Let's say a vent with a diameter of 96 mm, or two of 68 mm diameter flooding at the same angle, i.e. (So the word "combined" in the rule)

Are these 6.2.2 and 6.2.3 included in which of the ISO Books? I find it frustrating to pursue requirements scattered around And further do they include requirements for bigger watertight (like companionway" hatchess



What amazes me is why there are people who think they have the right to cross an ocean without the proper equipment, but we do not see the same kind of people claiming for that same right to cross the Kalahari, climb the Everest or just go deep diving.[/I]

Believe me, they do that too

My problemo is the same as stated from Nauticat

"Hello Mr. Gefaell
The stability of the boat is more than enough for category A, but it is the side doors, which makes it extremely difficult to get it in category A, as those are considered as flooding openings.
I hope this explains the situation. The same thing with our Nauticat-331 and Nauticat-44.
best regards
NAUTICAT YACHTS OY
Veli Kärjä"

Allthough it's not a real problem but if there's a possibility to make a ISO approved watertight side door (non flooding) so I'd like know how

 

Are you asking what is the pecific ISO rule where those were taken from? I do not have the norms here, but I think I mentioned which one it was ( It would be nice if you tell me which of my many posts is the one you now quote). Anyway, if you're seriously interested please send me a PM and I'll check the rules and tell you.

Without the proper equipment? I'll be grateful if you show me just a single case.

Ask this people:
http://www.pointeng.co.uk/marinedivision.asp
http://www.usaslidingdoors.com/
http://www.wkdoors.com/sliding-doors.htm
http://www.imsgroups.com/
http://www.grumsen.dk/Default.asp?ID=129
http://www.winel.nl/cms/index.php?option=com_content&task=view&id=26&Itemid=87


Cheers.

 

I think found even better in post 36:
"c) watertight compartments used to provide buoyancy shall be constructed to watertightness degree 1 in accordance with ISO 11812 and hatches and doors satisfy watertightness degree 2 of ISO 12216"

Believe these standards are what I'm looking for. However I'm not familiar how all the ISO standards are organized and published so I'm not sure are these relevant with the ISO 12217-2? I'll check up some details tomorrow and study the links you gave and send PM after that..

Discovery or NatGeo channel had a series about Mount Everest Season. They showed a couple cases where some groups of climbers were going to the Death Zone without even emergency Oxygen or meds to handle Odema (insulin?). Without like suicide attemp...
Deep Diving is something every now and then someone tries with ordinary recreational scuba setup. It means no redundancy, inadequate gas supply, using air instead of mixed gases (Trimix= He, N, O;Nitrox or O2 for Decompression) no planning etc...
So a rowboat to China is quite sound compared to some of these loonies...

 

And the factor never considered is the SCF and ICF
the first very important is: The sick crew factor
The second: The incompetent crew factor.
For the STIX we can put a thousand more factor it will kept the push papers in Bruxelles very busy and the big production boat almost alone on the market since the STIX is quite tailored for them. More paper work is exactly what we need! Architecture naval degenerate in sort of paperwork competition, machines punching number without talents to pretend the boat designed is perfect, since the STIX is perfect and the software too! But the fact production boat with perfect STIX number lost there keel don't bother nobody since they are perfect. The fact they capsize and stay upsidedown don't bother nobody since they are perfect. The STIX miracle, the Parthenon of stupidity and waste of time.

 

dskira,
Well, I would not say STIX is the Partenon of stupidity and a waste of time, because it is not. Problem is it is being taken as what it is not. Here some of my first words when opening this thread:

"....As we can see 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.
.............

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."
..............

The problem is that as people understand almost nothing about these matters, they tend to fix to a simple rule, as it couldn't be other way. And STIX is becoming dangerously a kind of 'magic' number among boatowners. What is worst, this Design Categories scheme is tending to confuse people's judgement on a boat's ability to survive bad weather, in my opinion. I think nowadays Category A means in a growing number of people minds, that the boat is able to go anywere, which is not true even under the RCD. Categories are a clue but not a 'Safety Act'. In my opinion this misunderstanding is being consistently encouraged by manufactures; and designers as well....

Taken from the "Recreational Craft Directive and Comments to the Directive Combined":
"The directive does not include any navigation or usage rules and there is no link between the design categories and any such rules; taking into account construction safety, the user is only clearly informed of what the boat was designed and built for in relation to certain parameters of significant wave heights and wind speeds."


Your SCF and ICF factors are not considered in the STIX, not in any other boats evaluating system, indeed, but in the 'Old' ratios one there are some of them trying to reflect the quality of the movements of a boat, as they are the Motion Comfort Ratio (MCF) and the SI Stability Index (SI).

Cheers